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Evaluating Carolina Bays As Surface Features In A Distal Ejecta Blanket:
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Geophysical Flow Analysis Predicts Bay Orientations
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Running Tile: Carolina Bays As Distal Ejecta
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Michael E. Davias1 and Jeanette Gilbride2
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Corresponding author: Michael E. Davias
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e-mail: Michael@cintos.org
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phone: 203-329-9044
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Unaffiliated, 2 North Carolina State University
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Abstract
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The aligned oval basins known as "Carolina bays" are rimmed by distinctive deposits of siliciclastic
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sands. This stratotype is notable for its lack of terrigeneous detritus, leptokurtic coarse-skewed size-
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frequency grain distribution, hummocky cross-stratification, and invariant mineral composition at any
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given locale. Gradualistic processes are commonly held accountable, although this specific
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combination of traits is challenging for eolian, fluvial or marine depositional mechanisms. As an
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alternative mechanism, we posit the distal emplacement of an ejecta blanket, rendered as fluidized
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sand, emanating from a cosmic impact into sedimentary strata beneath the Wisconsinan ice sheet. We
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interpret the basins to be voids created within the superheated ejecta blanket during a high-energy
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deposition, such that basin orientations may represent the ejecta's arrival bearing, facilitating the use of
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a triangulation network to identify the source crater. Previous attempts to triangulate bay orientations
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have failed, as large-scale geophysical flow effects of an ejecta distribution were not considered. To
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test our hypothesis, we engineered and implemented an analytical model to generate arrival bearings
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reflecting ballistic trajectories over a rotating sphere, and its results compared to bay orientations seen
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in a catalogue representing ~100,000 basins across North America. Our model's predictions correlate
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well with actual bay orientations when an oblique cosmic impact in the Saginaw area of Michigan is
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considered. Results from our research imply that the Carolina bays are depositional artifacts in an
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ejecta blanket, chronologically constrained to ca 40.5 ka. A web-based version of the model is
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available to facilitate independent testing of the hypothesis.
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Prologue
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In his scholarly examination of numerous then-current hypotheses for the genesis of Carolina bays,
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Douglas Johnson stated: “No one has yet invented an explanation which will fully account for all the
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facts observed” (1942). 70 years later, the geomorphology of these ovoid basins continue to challenge.
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Their sheer numbers, bedding in an anomalous stratum of homogeneous sand, distinctly geometrical
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circumpheral rims, variety of sizes, and common alignments across significant relief in any one area
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are seen by us as enigmatic. We view the bays collectively as a geological singularity, justifying a non-
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classical solution. Although it is possible that future models and/or observations may solve this
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enigma, it has motivated us to explore a potential independent solution. The genesis of this exploration
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was a visit made by the authors in 2005 to an expansive exhibit about the Carolina bays at the North
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Carolina State Museum of Natural Sciences, Raleigh, North Carolina.
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The inspiration for our ejecta deposition hypothesis was an observation by R. B. Daniels, et al (1970):
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The Goldsboro ridge is a unique feature on the Sunderland surface and requires special
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explanation whatever its origin. It must be either an erosional remnant of a once more extensive
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sediment or a depositional feature. ...The Goldsboro sand overlies the Sunderland Formation
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conformably. The contact is always abrupt but there is no evidence of deep channeling, basal
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coarse material, and evidence of weathering at the contact. Even the Carolina Bays do not disturb
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the underlying Sunderland materials.... The sand in the bay rim is not different from the Goldsboro
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sand. Therefore, these Carolina Bays are merely surface features associated with the formation of
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the ridge.
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3
1 Introduction
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Photographs of the Carolina bays have been available from the air since the early 1930’s. Those early
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images sparked extensive research into their genesis, yet they reveal only a small part of their unique
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planforms. Digital elevation maps (DEM) created with today’s Laser Imaging and Range Detection
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(LiDAR) systems accentuates their already-stunning visual presentation, allowing for the identification
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and classification of even greater quantities of these shallow basins across North America (Post, S. H.,
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et al 2009). Our research was enabled to a large part by the facilities and satellite imagery of the
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Google Earth (GE) Geographic Information System (GIS), augmented with LiDAR imagery.
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Researchers generally consider the bays to be formed within or excised from pre-existing strata
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through impact or by eolian, fluvial or marine (or combinations) processes. (Prouty, 1952; Eyton &
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Parkhurst, 1975, Ivester, et al, 2007). On case-by-case evaluations, certain bays will be satisfactorily
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explained, but those explanations never fit more than a small subset of the depressions and fail
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Johnson’s “fully account” test. Some of the characteristics are seen in sand dunes or wind-oriented
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paleolakes; such comparisons are unsatisfactory to us. While we are proposing a cosmic connection,
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we also fully support the conclusions reached by Dr. Johnson (and by numerous others in more recent
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research), which have comfortably dismissed either primary impact or secondary impact events for the
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bays geomorphology.
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In direct contrast to all previous work, we propose that the bays are surface features within a blanket of
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ballistically deposited ejecta, draped conformably over antecedent topography and creating a
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palimpsest upon which much geological history has been written in the form of lacustrine and eolian
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development within and about those basins. We maintain that all of Johnson’s observations dismissing
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an impact scenario can be viewed as supportive of a blanket deposition, although he did not entertain
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the possibility. Notable among his observations in which we see correlation are:
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Unit structure of the rim and surrounding pediments (single stratum)
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Homogeneity of characteristics across the rims’ bulk
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Challenging lack of terrigeneous detritus in the stratum
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Rim material is not locally derived from underlying strata (nor do they deform them)
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Overprinting of pre-existing drainage channels
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Transgression of those channels across the bay’s rims at inappropriate locations
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1.1 Carolina bay Geomorphology
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The hypothesis holds that glacial ices, excised sedimentary strata, and elements of the impactor
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shattered into small particles during the cosmic impact and intermixed in the ejecta curtain wall. The
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resulting 1-10 meter-thick layer of distal ejecta was spread differentially across North America,
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primarily within an annulus located at 900 to 1400 km from impact. We posit that relatively shallow
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basins were created as surface features during the energetic deflation of steam inclusions in the ejecta
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blanket; effectively “popped bubbles”, often manifested as a void in the blanket. This high-
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temperature, high-pressure emplacement created an unconsolidated rim stratum that has maintained its
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structural integrity over time. The authors believe this interpretation explains the bays’ geophysical
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characteristics, such as companion bays across a continuum of elevations, occasionally intersecting or
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overlaying one another, as well as the creation of bays on ridges which are themselves comprised of
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identical homogeneous sediment (which is our interpretation of the Goldsboro Ridge in North Carolina
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(Daniels and Gamble, 1970)).
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Other workers proposing classic geomorphic mechanisms for the genesis of these enigmatic landforms
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(Grant, et al., 1998, Ivester, et al., 2007) have, in our opinion, not taken the opportunity to view these
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striking oval planforms using high-resolution LiDAR imagery, their planforms repeating in quantities
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of hundreds of thousands. Figure 1 displays the typical assortment of bay planform as existent across a
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~1,400 km2 area of North Carolina. We see the visualization of bays, both in size and juxtaposition, as
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a simple physical fractal distribution. We demonstrate such a distribution in a field of soap bubbles, as
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shown in Figure 2. The interiors of many Carolina bays possess classic lacustrine sediment
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stratigraphy and enclosing shoreline sediments, which is fully appropriate for a basin existing for tens
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of thousands of years in areas of high water tables.
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1.2 Annular Distribution of Siliciclastic Sand as Ejecta
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Our hypothesis proposes that distal ejecta at 1,000 km distance from a cosmic impact (~5 crater
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diameters) would be materialized as an annular ring of hummocky sand deposits. Distal ejecta from
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the recent oblique impacts of the SL-9 fragments into Jupiter have been imaged and evaluated as
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distributed along an annular ring, offset laterally and downrange of the impact trajectory. (Harrington,
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2003). Other workers have comfortably verified the bay’s coarse-skewed sand rim stratum as being
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anomalously uniform in grain size, mineral content and color across their horizontal and vertical extent
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at a given bay. Our proposal offers an explanation for this, as an individual bay’s bulk ejecta are likely
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derived from the shattering of a common sedimentary unit during crater excavation, while allowing for
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the variability of sand composition seen at other bays as the impactor proceeded through other
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sedimentary units.
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We interpret the presence of coarse sand ejecta at the identified distances of 900 km to 1400 km to be
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attributable to the differential winnowing out of components from the ejecta curtain wall as a function
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of density. We predict that lighter components would have experienced longer loft times, while higher
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density components would fall out of the expanding curtain wall closer to the impact site. We also
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suspect grain size sorting within the ejecta curtain wall may play a role in yielding the tightly
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constrained range of coarse skewed grain sizes seen in individual bay rim deposits. The preference for
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creation of bay depressions at these distances is not well understood, but may be associated with the
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delivery of the posited superheated hydrous mixture only within those distances, based on a pressure
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gradient in the expanding ejecta curtain wall.
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While the common view of ejecta is as cobbles or melt (near field) or microscopic particles (at global
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distances), we deem it appropriate to propose an intermediate class of ejecta similar to the deposits
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seen in the Carolina bay rims and pediments. Studies of ejecta from the Chicxulub event has identified
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distal (~1,000 km) deposits of sandstones comprised of coarse skewed, homogeneous clastic quartz
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constituents, seen in a mottled, unstratified unit measuring in the tens of meters in vertical extent
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(Goldin,T., 2009; Schulte,et al,. 2010; Bralower, et al., 2010), although uncertainties exists as to their
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relationship to the impact.
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1.3 The Saginaw Impact Crater
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The lack of a correlated impact structure in North America is problematic for any attempt to implicate
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a cosmic impact in the genesis of the Carolina bays. While it is beyond the scope of this exercise to
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fully validate our selection of the Saginaw area of Michigan as a proposed impact location, we feel a
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brief presentation of our argument is appropriate here.
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Using the measured alignments of an initial 40 Carolina bay fields, we generated great circle paths for
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visualization in Google Earth. This yielded a fuzzy triangulation locus centered at 43.5 N, 89.5 W.
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Our analysis implies that a great circle triangulation would yield an erroneous “surrogate” impact
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location, offset to the west. A flight-time adjustment of the crater eastward along the 43.5º N Parallel
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(taking into account the Earth rotating .25 degrees of arc every clock minute) directs us towards the
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actual impact site (discussed in more detail in 2.3.2). We heuristically examined various geological
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depression found along that transit, and selected the Saginaw area of Michigan’s Lower Peninsula for
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further analysis. `
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The authors are respectful of the acceptance of the Saginaw area as a glacially carved landscape.
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Indeed, we propose the presence of a thick ice sheet over the Lower Peninsula on the impact date. The
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ice sheet offers a rationale for the relatively shallow “crater” seen in the area today, while at the same
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time providing the significant volume of water necessary to create the posited hydrated slurry.
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Implicating the ice sheet also provides a vehicle to re-distribute the local crater ejecta across a wide
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area as “glacial till”. A cross-section schematic of the proposed crater is shown in Figure 3.
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It is generally understood that glacial activity removed vast quantities of softer strata from around the
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Michigan Basin’s periphery (i.e., Lakes Michigan, Huron and Erie), however the ice sheet was
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unsuccessful in breaching the cuestas encircling the center of the basin with one major exception –
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Saginaw Bay (Rieck and Winters, 1982).
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Our hypothesis holds that the impacting object was a massive low-density hydrated silicate object,
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likely a cometary body, which impacted the Earth on a shallow angle, nearly tangential to the Earth’s
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surface. Remote sensing has show that approximately 5% of all craters are created during such oblique
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impacts, creating a set of recognizable characteristics: oval shape, butterfly ejecta pattern, “no-fly”
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ejecta area up field, and “blow-out” rim down field. (Herrick, R.R, 2009; Herrick R.R. and K. Hessen,
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2003). Recent studies suggest that impacts into solid surfaces protected by a layer of low impedance
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materials produces structures that differ from classic planforms (Schultz, 2007; Schultz and Stickle,
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2009). In our specific case, we invoke the Wisconsinan ice shield as a low-impedance layer protecting
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the sedimentary strata of the Michigan basin. The mechanism for removal of terrestrial material is seen
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as shearing rather than compression, thus many of the classic impact markers (such as shocked quartz)
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are not expected.
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Using remote imaging tools, we note that the Saginaw region exhibits a geometrically oval shaped
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depression, oriented SW to NE, which correlates well with the ejecta symmetry (see Figure 4).
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Research by others utilizing remote sensing tools (Herrick and Hessen, 2003) have shown oblique
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impact craters often display the deepest excavation at the up range end of the crater, which here falls in
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the northeast end of our proposed Saginaw crater, where one of the deepest areas of Lake Huron exists
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– the Bay City Basin. Another attribute of oblique impact planforms is a ridge – likely rebound strata –
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down the center of the structure. Here, the Charity Islands exist along the oval’s centerline.
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We expect that the Huron lobe of the Ice sheet would have advanced into the excavated crater from the
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Huron basin, bulldozing the collapsed ice crater ramparts, leaving the present-day terminal moraines
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behind as it deglaciated. Research has indicated that the Saginaw lobe was absent from southern
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Michigan while the Lake Michigan, Huron-Erie, and Erie lobes continued to advance during the latter
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part of the Wisconsinan glaciation (Brown, et al., 2006).
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1.4 Ejecta Flow Analytical Model
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An ejecta curtain wall radiating outward from an impact site should follow a few basic physical laws
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involving ballistic trajectories over a rotating spherical surface. We present a heuristically engineered
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analytical model that replicates those trajectories and generates a prediction of bay orientations, based
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on the momentum/velocity vectors that would have been inherent in the ejecta blanket at the moment
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of emplacement. The model is controlled by two variables related to the velocity of the ejecta in the
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ground plane: average velocity of the loft (as an input parameter) and terminal velocity during
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atmospheric re-entry (calculated from ejecta property parameters: density and a coefficient of drag,
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Cd). A positive correlation between the model-generated orientations and actual bay orientations
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could be considered as validating the relevance of the model’s algorithm and offer support for the
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distal ejecta blanket hypothesis.
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2 Methods
2.1 Determining the Geographical Extent of Carolina bay landforms
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Using the facilities and satellite imagery of the Google Earth GIS, augmented with high resolution
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LiDAR imagery, a survey was undertaken to catalogue the extent of Carolina bays, indexed as
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localized “fields”. The Global Mapper GIS application was used to generate LiDAR image overlays
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for visualization in Google Earth, using 1/9 and 1/3 arc-second DEM data from the United States
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Geological Survey (http://nationalmap.gov/viewers.html), and 1/9 arc-second DEM data from the
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Nebraska Department of Natural Resources (http://dnr.ne.gov/floodplain/lidar.html).
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Estimations of the bays’ numerical quantity extends into the hundreds of thousands, therefore no
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attempt was made to identify all such landforms; instead each field was selected to be rigorously
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representative of the distribution in a given locale.
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Identifying Carolina bays on the costal plain is straight forward, given their solid identification,
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however bay planforms tend towards a circular presentation in the northern and southern extremes of
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their geographic extent, presenting challenges. Also challenging is the rougher terrain seen when
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moving inland. If a landing area is level and moist, we propose the bays will be stabilized. Conversely,
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if the area is dry, the blanket will be reworked into a generic dune field, obliterating any bay formation.
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When the landing field is in rough terrain, we propose it is sloughed off. We suspect that access to high
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resolution LiDAR DEMs in more regions would aid in expanding the bays’ identified range.
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While there is much research discussing Carolina bays in the east, little attention has been paid to the
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significant quantity of aligned, oval basins in the Midwest (Zanner and Kuzila, 2001). These basins are
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aligned SW ➔NE (Figure 5), intersecting the eastern bay’s SE ➔NW orientations, and are considered
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to be vital components of the crater triangulation network.
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The survey resulted in a catalogue of ~220 fields of Carolina bays, managed in a spreadsheet database
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and in a Keyhole Markup Language (kml) metadata file. The catalogue is available for interactive
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visualization on Google Earth’s virtual globe using the kml file available at
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http://cintos.org/ge/SaginawKML/Distal_Ejecta_Fields.kmz. A basic text listing of the fields is
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presented in Appendix A.
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2.2 Assigning Bay Arrival Bearings
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Our working hypothesis that Carolina bays represent depositional features in an ejecta blanket leads to
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a corollary that the arrival bearing is a momentum artifact, aligned along the bays’ major axis. To
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measure and capture this alignment, we employ a graticule overlay on Google Earth’s virtual globe
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(Figure 5). The overlay is manually rotated so that it aligns with the user’s interpretation of orientation;
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the rotational value is captured in the overlay’s metadata. Since bays are rarely perfect ellipsoids and
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have often been reworked by other processes, the interpretation is better qualified by comparison with
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companion bays, so as to be representative of all basins in the immediate area.
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While the bays of North and South Carolina are seen as elongated ellipsoids, bays to the north and to
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the south, often do not present the elongation necessary for determining orientation. We do see a
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predisposition for having a segment of the enclosing rim that is wider & higher than the opposing side.
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For the purpose of this discussion, we have interpreted the “alignment” of near-circular bays to be
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from the shallow side to the wider rim.
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2.3 Correlating Carolina bay Orientations
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Attempts by others to correlate bays’ orientations across their extent have failed (Eyton, J.R. and
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Parkhurst, J.I., 1975), as they typically were accomplished by drawing straight lines on flat-earth maps.
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We propose that satisfactory correlation can be obtained by applying several physical aspects of
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planetary-scale ejecta trajectories, a process not considered as relevant by previous workers. First, the
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impact may have generated ejecta from a broad geographic extent. Secondly, a planetary body rotates
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during any realistic ejecta flight-time. Third, the west-to-east ground-velocity between the ejection site
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and the landing site differs, and the difference will be resolved as the ejecta re-enters the atmosphere
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and strikes the Earth. Also a factor is the interpretation of a given bay’s orientation, as the bays rarely
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present a geometrically pure ovoid form (Johnson, D., 1942). The reader should consider that generic
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computations for ballistic physics do not need to consider the resulting ground-plane velocity vector
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when determining a singular point-of-impact.
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2.3.1 Bearing Adjustments Based on The Spherical Earth Surface
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Ejecta will follow a great circle path as it proceeds along a trajectory. For example, if an object is
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launched with sufficient velocity on an azimuth of 90º from latitude 45º North (i.e. due East), it will
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follow a great circle route as it begins to circle the Earth’s surface. The Cartesian coordinate “bearing”
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of our example object begins to “turn” south, and eventually crosses the equator on an azimuth of 135º.
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During the flight period the Earth would be rotating beneath the ejecta’s trajectory path; the landing
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location of the ejecta will actually be westward of the static-Earth target.
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2.3.2 Bearing Adjustments Based on A Rotating Earth
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Restricted to a static, non-rotating Earth, a set of Great Circle trajectories can be tracked backward
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using Carolina bay measured arrival bearings to create a triangulation network. The locus of any such
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triangulation would be erroneously offset westward based on the Earth’s rotation of 1 degree of
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Longitude for each 4 minutes of ejecta flight-time. Further, that flight-time is based on the loft distance
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and average transit velocity. To address this, our model’s algorithm considers the perspective of the
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emplaced ejecta site and applies a conceit that a static-Earth surrogate “target” site can be envisioned
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offset eastward using that same formula. Significantly, we interpret the bearing of the velocity vector
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seen at the surrogate “static-Earth” target as the relevant value imprinted in the bay’s orientation, rather
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than one derived from the geometric relationship between the cosmic impact site and the actual
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rotating-Earth emplacement site. We will consider the static-Earth arrival bearing value at the
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surrogate target to be the “baseline”, which is further refined in the model’s next step.
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2.3.3 Bearing Adjustments Based On Latitude
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While the Coriolis force component is systematic by flight-time, there is another factor superimposed
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on alignment that is systematic by latitude. Here, we account for ground speed differences between any
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two particular spots on the earth, which is a function of the cosine of the locations’ latitudes. The end
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cases are the poles – where the ground velocity W➔E due to rotation is negligible – and the equator –
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where the ground speed W➔E is ~1,670 km per hour.
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Using a specific example, the surface rotational velocity of the proposed Saginaw crater is 1208 km/h.
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Material ejected eastward and arriving at Bishopville will interact with the atmosphere and surface
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rotating at 112 km/hr faster. Combining the static-Earth ejecta velocity and relative ground velocity
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vectors causes a) atmospheric push of the ejecta and b) target drag resulting in a target contact velocity
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vector, which will be rotated relative to the static-Earth velocity vector.
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2.4 The Analytical Model
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We present a model for an ejecta curtain wall radiating outward from an impact site that represents the
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adjustments made for ballistic trajectories over a rotating sphere (discussed in 2.3), heuristically
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engineered to predict Carolina bays’ orientations. It was our intent to only identify and address first-
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order magnitude effects, given the expected chaotic distribution of ejecta velocities, densities and
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directions. Numerical methods to evaluate ballistic trajectories at a planetary scale have been
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developed to generate flight distances and distribution envelopes (Jessup, K.L., et al., 2000). While
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those are relevant calculations for some aspects of our study, they do not attempt to predict flow
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orientations at emplacement.
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Our Carolina bay catalogue spreadsheet was extended with analytical formulas to generate predictions
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based on the spherical-Earth, flight-time and latitude adjustments, enabling it to generate a solution for
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each catalogued field’s predicted bearing while physically relevant parameters such as average and
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terminal velocity for the ejecta are adjusted. Charts are generated within the spreadsheet to correlate
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the predicted bearing values with measured values, allowing heuristic tuning of the variables to
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identify best-fit solutions simultaneously across all bay fields. The spreadsheet also generates
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catalogue-wide sets of KML to visualize on the Google Earth virtual globe.
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A Java calculator was developed in parallel with the spreadsheet, and specifically engineered to
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interface with the Google Earth virtual globe. Using the Google Earth "Placemark" metadata element,
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the location's latitude and longitude (typically the center of a bay) are captured and annotated. The
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calculator processes the placemark and returns a set of Google Earth elements that represent the
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numerical model's predicted ejecta arrival vector. The model is heuristically focused on the latitude
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and longitude of the proposed Saginaw crater’s three control points (NE, Centroid and SW); the
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calculator returns predictions for ejecta emanating from those three locations. The graticule alignment
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overlay, previously mentioned, is provided for the visualization of the vector on the virtual globe,
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rotated to reflect ejecta emanating from the crater centroid.
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The calculator also has a function used to invert the numerical process. Here, a user-adjusted alignment
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overlay on the virtual globe is used to capture a best-guess visual match with the bay orientation (see
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Figure 5). The overlay element is processed by the calculator, which returns a triangulation trajectory
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to a putative crater. In all cases, the data transfer is accomplished by using Google Earth's "Keyhole
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Markup Language" (KML), a dialect of XML specifically created to encapsulate geographic
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information system datum.
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We note that the calculator’s two functions represent true inverted calculations. As such, an arrival-
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bearing vector generated by the prediction feature, when then used as input to the triangulation feature,
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will always generate a trajectory back to the ejection location used in the original prediction.
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2.4.1 Model Variables
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The model’s variables are segregated into those that are adjusted at each evaluated site (the latitude and
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longitude of the bay location) and those currently applied as constants across all predictions (selected
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by best-fit solution across all evaluated bays, but can be adjusted by the user). The latter are explained
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below:
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A) Crater latitude and longitude parameters (selected as Centroid: 43.68N, 84.82W, Rampart
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SW: 43.724N, 84.944W, Rampart NE: 44.624N, 82.659W)
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B) A reasonable average ground-vector velocity for the ejecta, as heuristically derived from our
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analysis. Satisfactory simultaneous solutions range from 1km/sec to 5 km/sec, with 3km/sec
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selected as default based on sensitivity testing.
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C) Three variables to generate a reasonable terminal velocity V (currently 381 m/sec) using a
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generic formula, for arbitrary 1-meter diameter “droplet” of ejecta:
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V = sqrt ( 2 * W) / (Cd * r * A),
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where W is droplet weight, (in Newtons), r is a density variable (selected as 2,000
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kg/meter^3) , and A is the frontal area of that droplet. Cd is the Coefficient of drag of
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the ejecta droplet (selected as 0.3).
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D) An incidence angle for ground impact to resolve ground-plane velocities (selected as 45º
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from vertical). The resulting ground vector of terminal velocity is 269 m/sec with the
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default variables.
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2.4.2 Calculations for Flight-Time and Longitude Offset Values
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The longitude offset calculation for a given bay location is derived using a simple flight-time to
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longitude relationship:
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Longitude offset in degrees = Flight-time (minutes) /4
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Where Flight-time = Loft Distance / Average Ground Velocity (default 3 km/sec)
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The Loft Distance between the crater centroid location and that of the bay is derived using the
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spherical law of cosines, applied in the following Java routine. All variables in radians:
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private double GreatCircleDistance(double lat1, double lon1, double lat2, double
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lon2) {
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double dLat = (lat2 - lat1); double dLon = (lon2 - lon1);
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double a = Math.sin(dLat / 2) * Math.sin(dLat / 2) + Math.cos(lat1)
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* Math.cos(lat2) * Math.sin(dLon / 2) * Math.sin(dLon / 2);
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return (EarthRadius * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a)));}
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2.4.3 Determining Baseline (Static-Earth) Bearing
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Once determined, the model uses the longitude offset value to identify a surrogate static-Earth target to
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the east of the bay, by subtracting the offset from the bay’s longitude value. The surrogate target site is
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then used to generate a baseline arrival bearing for ejecta as lofted from the impact crater’s
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coordinates. A java routine is invoked to generate the bearing as seen from the surrogate bay target
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(lat1, lon1) towards crater control point (lat2, lon2). We invert the bearing 180º to create an arrival
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bearing. Functions convdr and convrd are used to convert between radians and degrees:
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private double GreatCircleBearing(double lat1, double lon1, double lat2,
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double lon2) {
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double y = Math.sin(dLon) * Math.cos(lat2);
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double x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)
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double dLon = (lon2 - lon1);
* Math.cos(lat2) * Math.cos(dLon);
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double Bearing = 180 + (Math.atan2(y, x) * convrd);
352
return (Bearing * convdr); }
17
353
The process above is performed three times, identifying a base bearing for each of the three crater
354
control points.
355
2.4.4 Applying Latitude-difference Adjustments to Base Bearing
356
Figure 6 depicts the trigonometry used to adjust the arrival bearing prediction based on the latitude-
357
driven W➔E Earth ground and atmosphere rotational velocities. In our specific proposal, a relevant
358
set of W➔E velocities would be the Saginaw crater – rotating at 1,208 km/hr – and a generic ejecta
359
field such as Bishopville – rotating 112 km/hr faster (deltaV). We first decompose the ejecta’s
360
terminal velocity vector (termv) to yield its W➔E component, using the base bearing ( “_C”
361
references the centroid calculation, also done for _SW and _NE):
362
EWcomponent_C = termv * Math.cos(baseBearing_C) + c_deltaV;
363
Next, the bearing is re-composed using ACOS and the adjusted W➔E component:
364
componentBearing_C = Math.acos( EWcomponent_C / termv);
365
Finally, the bearing is cast into the proper compass quadrant (lost in the ACOS trigonometry) using a
366
previously extracted compass quadrant of the static-Earth base arrival bearing:
367
PredictedBearing_C = ((componentBearing_C * convrd) + (latQuadrant_C * 90));
368
The full Java code set includes routines to deal with compass cardinal point crossings and modulo 360º
369
adjustments required for conversions between trigonometric notation (-180º ➔ +180º) and compass
370
bearing spherical notation (0º ➔ 360º). The model uses the predicted bearings to generate Google
371
Earth kml visualization elements (paths, overlays and placemarks) for display in the GIS viewer.
18
372
2.5 Independent Testing of Hypothesis
373
To facilitate independent testing of the hypothesis, a web-based Java calculator version of the
374
analytical model is available for interoperation with Google Earth (GE). A bay’s latitude and
375
longitude are captured using a “Placemark” kml element, which the calculator uses to generate a
376
predicted orientation for visualization in GE. The calculator can also invert the algorithm, providing a
377
“walk-back” to the putative crater by processing a user-adjusted overlay element (representing their
378
interpretation of the actual bay orientation) as the input datum. Data transfers between GE and the
379
calculator are accomplished with kml metadata. Access to the calculator is via the web link
380
http://cintos.org/java/PredictBearings/PredictBearings.html , which requires a Java-enabled browser to
381
execute, and access to a Google Earth run-time instance to exchange kml data with, allowing for the
382
visualization of the predicted trajectories on the virtual globe.
3 Results
383
384
3.1 Geographical Bay Distribution
385
Our first correlation considers the great circle distance from each field back to the proposed impact
386
site, and their symmetrical distribution around it. As shown in Figure 7, a high degree of correlation
387
exists, suggesting that the bays are geographically placed in an annular distribution centered on the
388
Saginaw impact. Loft distance to the Midwest are nearly identical to those in Southeastern areas,
389
suggesting a general trend of longer flight distances down range compared to those normal to the
390
crater’s major axis, which display shorter flight distances.
19
391
The geometric shape presented by the coastline of the Eastern US, and its hospitable hosting relief
392
compromises our interpretation of the arcs to some extent. This concern is partially addressed by the
393
solid correlation of the Nebraska bays’ loft distances to those in the Southern US.
394
We assume that areas north of the impact site were covered in glacial ice sheet at ~40 ka, prohibiting
395
the survival of bays that may have been created within a supraglacial ejecta blanket. There are
396
indications of a significant supraglacial clastic deposition over Wisconsin, Minnesota and the Dakotas
397
during the Wisconsinan glaciation, however. We propose that a supraglacial blanket of debris is
398
responsible for the large quantity of ice walled lake plains existent across that region, created by a
399
process that demands the presence of a thick cover of supraglacial sediment. Workers currently
400
implicate stagnant ice mechanisms for the required supraglacial material, although such conditions are
401
unexpected in the quantities found at great distances from terminal ice margins, and where offshore
402
sediment deposits measuring in the tens of meters have been identified (Clayton, et al., 2008).
403
3.2 Predictions of Bay Orientations
404
The ~220 evaluated bay fields represent many thousands of individual bays, and our solution sets are
405
computed across all of them simultaneously. The results we present were generated using constants for
406
all input parameters, the exception being the individual bay’s latitude and longitude values. The chart
407
in Figure 8 presents results obtained using our current best-fit parameter settings of 3-km/sec average
408
velocity and a droplet density of 2,000 kg/m2 and Cd of 0.3 (yielding a terminal velocity of ~270
409
m/sec). A robust correlation is shown between the measured bearings and the predicted bearings.
410
While it would seem plausible that the ejecta at any given location may actually have a varying density
411
or velocity, the model did not need such fine-tuning to arrive at satisfactory solution.
20
412
3.3 Variable Sensitivity Testing
413
We have identified a range of variable value sets, each of which will generate valid bay orientation
414
predictions simultaneously across all bay fields. A variable sensitivity analysis is graphed in Figure 9.
415
Generic ballistic computation programs yield flight-times in the range of 4 to 8 minutes for the
416
distances involved, assuming solutions where the arrival angle of incidence is shallow enough to
417
produce the expected momentum-driven elongation of the bays. Given our current field catalogue, the
418
use of a 3.0 km/sec average flight velocity (in ground plane) yields an average loft time value of 5.86
419
minutes.
420
3.4 Estimation of Ejecta Distributed Volume
421
Generation of a 1 to 10 meter blanket of ejecta across the proposed annulus necessitates a very
422
significant volume of material. While the overlying glacial sheet provided a significant portion of the
423
proposed ejecta, its volatile nature mandates that it cannot be considered in any current-day deposits.
424
Terrestrial minerals from the Saginaw Basin’s sedimentary strata and elements of the impactor are
425
therefore considered here.
426
Our proposed Saginaw crater was engineered in Global Mapper as an oval Path Profile upon the USGS
427
1/3 arc second DEM data for Michigan’s Lower Peninsula. The programs “Fill” function was used to
428
calculate the amount of material to fill the oval up to an elevation of 300 meters above mean sea level
429
(MSL) from the current elevations, resulting in a volume of ca 20,000 km2. The floor of the Saginaw
430
Lobe is blanketed with a substantial layer of glacial till, which we propose was created by the in-flow
431
of local ejecta originally deposited on the ice shield, which later collapsed into the crater. While much
432
of the ejecta would be expected to be deposited locally, after accounting for the crater back-fill just
21
433
discussed, we suggest a budget 50% of the measured missing volume should to be applied to each
434
proximal and distal ejecta. The distal ejecta volume to be considered is therefore ~10,000 km3.
435
The impactor’s mineral content is proposed by us to be rendered into siliciclastic elements, similar to
436
the excised terrestrial sedimentary. We propose a speculative-sized 20 km-diameter impactor would
437
yield an additional ejecta distribution. Given a sphere’s volume
438
= 4/3 • π • r³
439
, the calculation yields an additional ca 4,000 km3 of ejecta. We speculatively budget ~50%
440
contribution to distal ejecta, or ~2,000 km3. Combined with the excavated component, a net ~12,000
441
km3 is proposed as the distal distribution.
442
The butterfly/annular distribution places ejecta across 70% of the annulus surrounding the crater, at
443
distances of 900 to 1,400 km. The area of an annulus A is given as
444
A = π • R2 - π • r2
445
, where R is the outer radius (1,400) and r is the inner radius (900). After accounting for the 70% aerial
446
distribution due to the butterfly pattern, the calculation yields an area of ~1.4 million km2. If we
447
consider the above budget of ~12,000 km3 distal ejecta, an average ejecta depth of
448
12,000 km3 / 1,400,000 km2 = .0085 km ≈ 8 meters.
449
The value is within the proposed 1 to 10 meters of blanketing ejecta. We acknowledge that this
450
exercise is quite speculative, but believe it demonstrates a reasonable accounting for the extensive
451
distal ejecta blanket proposed.
22
4 Discussion
452
4.1 Event Chronology
453
454
Geochronology techniques are available to place constraints on the timing of recent events, including
455
carbon dating, thermo-stimulated luminescence (TSL), optically stimulated luminescence (OSL), and
456
thermally transferred OSL (TT-OSL). Identification of a wide date range for elements of the bays’
457
underlying basin structure would falsify any impact hypothesis, and other workers have reported such
458
results (Ivester, et al., 2007) using OSL techniques.
459
Our position on OSL dating is that it does support our hypothesis if properly applied. In numerous bay
460
examples, we suggest the energetic formation of the burst-bubble rim generated a void in the ejecta
461
sheet, allowing core samples taken within the bowl of the basin to progress through the deposition
462
horizon and into the hosting strata with no discernable transition. This allows for a continuum of
463
chronological samples through the Pleistocene. OSL technology, with its dependence on exposure to
464
sunlight for multiple hours, has applicability to gradualistic sedimentary processes and may hold no
465
relevance within the context of a mass deposition of ejecta, while TSL may hold more promise given a
466
superheated ejecta regimen. Obviously, the environs around and within the basins were subject to
467
reworking and the infilling of newer sediment over the intervening millennia. Attempts at applying
468
dating techniques must discriminate between the two depositional sequences, and we propose that
469
constraints imposed by dating depositional surfaces immediately below and above the bay stratum may
470
be more appropriate. Our LiDAR images show numerous situations where true wind-driven dune
471
systems are overriding bay structures, at angles totally unrelated to the bays’ orientations; see Figure
472
10.
23
473
We call attention to several geological anomalies that may correlate with the Carolina bays and which
474
offer support for dating the event ca 40 ka:
475
1) Ejecta deposition on the scale proposed would have created collateral damage to the North
476
American environment. Burials of fauna, flora and paleosols would be evident beneath the blanket.
477
One example of this may be the ancient Baldcypress trees buried within a 10-meter deposit of white
478
sand near Pee Dee, SC, which are dated at ca 40 ka. (Stahle, D.H., 2005, available on line at
479
http://www.uark.edu/misc/dendro/subfossil.pdf). Stahle, et al, make an interesting observation:
480
The recovery of well preserved baldcypress logs from two separate deposits of late Pleistocene
481
age in South Carolina raises many interesting research questions. The most immediate
482
question concerns the genesis of the buried white sand layer and the many large subfossil
483
cypress logs it contains. Does the white sand unit represent a single depositional event or a
484
slow process of accumulation over centuries to millennia of time?
485
2) A sample of cypress extracted from the Canepatch Formation (considered to be deposited by a
486
higher energy mechanism) at Todd Pit in North Carolina, was C-14 dated at >45 kya. (Mabry, M,
487
2001).
488
3) Research addressing the mean sea level (MSL) history along the NC coast suggest that barrier island
489
deposits were created during the Marine Isotope Sequence (MIS) -3 high stand above the present-day
490
sea level, and - significantly - stratigraphically above the MIS -5 high-stand shoreline deposits
491
(Parham, et al., 2006, Mallinson, et al., 2008, Scott, T.E., 2010), which is in contradiction to MSL
492
sequences elsewhere across the globe. The Poquoson Member of the Tabb Formation (maximum
493
thickness of 4.5 m in southeastern Virginia) has been OSL dated at 39.6±6.6 ka and 44.4±5.2 ka, and
494
nearly identical dates of 39–47 ka for the Wachapreague Formation (Eastern Shore) have been
24
495
reported. (Scott, et al., 2005). Further south, a thick sheet of hummocky, coarse-grained fine sand at
496
Broad Reach, NC, was OSL dated at 42.5±3.72. This deposit is problematic in that its coarse-skewed
497
morphology is not usually associated eolian deposits, but the lack of fossil material, lack of heavy
498
mineral laminations, and lack of coarse-grained material, combined with a high degree of sorting point
499
to eolian as the only viable alternative considered by the workers (Mallinson, et al., 2008). While other
500
workers invoke complex glacioisotatic regimens across the southeastern US coastline to address such
501
challenges, the hypothesis proposes a 10-meter ejecta blanket deposit across the continental shelf as an
502
alternative mechanism.
503
4) An analysis of the sea levels during the most recent Wisconsinan Ice age suggest that a
504
strengthening of Mississippi River outflow at 39 ka and an increase in sea level seen in four
505
independent measurement methodologies occurred at a time of decreasing temperatures in the
506
Northern Hemisphere. (Siddall, et al., 2008)
507
5) An examination of oriented Nebraska basins (Kuzila, M.S., 1994) has shown that late Wisconsinan
508
loess deposits dated ca 27 ka are draped evenly over hundreds of antecedent basin structures,
509
smoothing the basins’ sharp rim relief, however not affecting their oval planform. Onset of similar
510
loess deposition over an antecedent basin at Bignell Table, NE has been dated ca 39 ka. These results
511
suggest the structural basins were deposited prior to 39 ka.
512
6) A review of glacial outflows after ~20 kya has show that the “Saginaw Lobe” had vacated the
513
southern area of Michigan earlier than previously assumed, while the Michigan, Huron and Erie lobes
514
continued their advance into the area (Brown, et al., 2006).
515
7) An expected outcome of a significant oblique impact would be the initiation of a geomagnetic
516
excursion event (Muller, R.A., 2002) where the magnetic pole of the earth either wanders or flips,
25
517
usually accompanied by a weakening of the overall geomagnetic intensity. Perhaps the strongest and
518
most enigmatic excursion in the last 790,000 years (which was the age of the last full reversal) is the
519
much-studied, intense, yet short-lived Laschamp event, dated at 40.5 kya (Guilloua, et al., 2004).
5 Conclusions
520
521
We have presented a concise and necessarily brief overview of an extensive hypothesis, which holds
522
that an oblique cosmic impact into the Wisconsinan ice sheet, ca 40.5 ka, ballistically spread a blanket
523
of distal ejecta across North America along a broad annulus. We propose that shallow basins were
524
created during the energetic deflation of steam inclusions in those ejecta. Those paleobasin foundations
525
have persisted over the intervening millennia as “Carolina bays”, “Rainwater Basins”, “Maryland
526
Basins”, etc, in spite of being overlain with loess and subjected to reworking by water and wind
527
erosion.
528
To test the hypothesis, an analytical model was engineered based on several fundamental
529
considerations of ejecta movement around a planetary-scale rotating sphere that hosts a dense
530
atmospheric envelope. The model has been shown to successfully predict trajectories and emplacement
531
orientations of the ejecta blanket and the surficial bays assuming only the source impact location and
532
bay locations on the sphere. While we demonstrate the accuracy of the model using constants for all
533
other parameters, variable sensitivity testing has shown that satisfactory predictions can be obtained by
534
perturbing the two physically relevant parameters (ejecta average and terminal velocities) over a
535
realistic range. The model can be inverted to identify a causal impact crater location using a
536
triangulation network. We also note that the distribution of bays is highly symmetrical around the
537
proposed impact’s azimuth.
26
538
The authors maintain that the correlations presented here demonstrate the existence of a unique
539
geospatial relationship between all known Carolina bays and the Saginaw region, and can be seen as
540
validation of the model’s algorithm and lending support for the distal ejecta blanket hypothesis
541
presented here. We encourage independent testing of our model using the on-line calculator discussed
542
here, and are open to collaborative efforts with other workers. It is our hope that the presented
543
argument will add a new perspective to the geomorphologic nature of the Carolina bays and
544
Michigan’s Lower Peninsula, thus warrant future research and investigation.
6 References
545
546
Bralower, Timothy, L. Eccles, J. Kutz, T. Yancey, J Schueth, M. Arthur and David Bice, 2010, Grain
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size of Cretaceous-Paleogene boundary sediments from Chicxulub to the open ocean: Implications
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for interpretation of the mass extinction event, Geology 2010;38;199-202, doi: 10.1130/G30513.1
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Brown, S. E., et al., 2006, New regional correlation of glacial events and processes in the interlobate
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area of southern Michigan and northern Indiana after the last glacial maximum, Geological Society
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of America Abstracts with Programs, v. 38, no. 4, p. 58.
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Clayton, Lee, J. Attig, N. Ham, M. Johnson, C. Jennings, K. Syverson, 2008, Ice-walled-lake plains:
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Implications for the origin of hummocky glacial topography in middle North America,
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Geomorphology 97, pp 237–248, doi:10.1016/j.geomorph.2007.02.045
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Daniels, R.B., and E.E. Gamble, 1970, The Goldsboro Ridge, an Enigma, Southeastern Geology vol.12
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Eyton, J.R. and Parkhurst, J.I., 1975, A Re-evaluation of the Extra-terrestrial Origin of the Carolina
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Bays, Occasional Publication, Dept. of Geography Paper No. 9, University of Illinois at Urbana–
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Champaign, p 45.
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Guilloua, Herve´, Brad S. Singer, Carlo Laj, Catherine Kissel,Ste´phane Scaillet, Brian R. Jicha, 2004,
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On the age of the Laschamp geomagnetic excursion, Earth and Planetary Science Letters 227,
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pp331– 343, doi:10.1016/j.epsl.2004.09.018
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Grant, J.A., Brooks, M.J., and Taylor, B.E., 1998, New constraints on the evolution of Carolina Bays
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from ground-penetrating radar: Geomorphology, v. 22, p. 325–345, doi: 10.1016/S0169-
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555X(97)00074-3.
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Goldin,Tamara, 2009, Atmospheric interactions during global deposition of Chicxulub impact ejecta, ,
Ph.D Dissertation, The University Of Arizona, 2008, 266 pp
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Harrington, J, I. de Pater, S. H. Brecht, D. Deming, V. Meadows, K. Zahnle and P. Nicholson, 2003,
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Lessons learned from Shoemaker-Levy 9 about Jupiter and Planetary Impacts, Chapter 8, in the book
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"Jupiter", Cambridge University Press, (ed. F. Bagenal, T. Dowling, & W. McKinnon), p. 159.
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Herrick R.R. and K. Hessen, 2003, The Impact Angles Of Different Crater Forms On Mars, Lunar and
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Planetary Science XXXIV, pp 2122.pdf.
Ivester, A.H., Brooks, M.J., and Taylor, B.E., 2007, Sedimentology and ages of Carolina Bay sand
rims: Geological Society of America Abstracts with Programs, v. 39, no. 2, p. 5.
Jessup, K.L., et al., 2000, Ballistic Reconstruction of HST Observations of Ejecta Motion Following
Shoemaker–Levy 9 Impacts into Jupiter, Icarus, 146, 19. doi:10.1006/icar.2000.6397
Johnson, D. W., 1942 , Columba Geomorphic Studies Volume IV, New York: Columbia University
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Kuzila, M.S., 1994, Inherited Morphologies Of Two Large Basins In Clay County, Nebraska, Great
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Mabry, Michele Y. And Thayer, Paul A., Sedimentology Of Pleistocene Waccamaw And Canepatch
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Formations, Todd Pit, Brunswick County, NC, Southeastern Section - 50th Annual Meeting (April
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Mallinson, David, S. Mahan, C. Moore, 2008, High Resolution Shallow Geologic Characterization Of
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A Late Pleistocene Eolian Environment Using Ground Penetrating Radar And Optically
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Stimulated Luminescence Techniques: North Carolina, USA, Southeastern Geology, V. 45, No.3,
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April 2008, p. 161-177
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Muller, R. A., 2002, Avalanches at the core-mantle boundary, Geophysical Research Letters, Vol. 29,
NO. 19, 1935, doi:10.1029/2002GL015938, 2002
Parham, Peter R., et al, 20085, Quaternary depositional patterns and sea-level fluctuations,
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northeastern North Carolina, Quaternary Research, Volume 67, Issue 1, January 2007, Pages 83-
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99 doi:10.1016/j.yqres.2006.07.003
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Post, Sidney H., P. Lee Phillips, and Nathan E. Phillippi, 2009, Using Lidar To Survey The
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Distribution Of Carolina Bays In Robeson County, North Carolina, Program with Abstract, GSA
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Southeastern Section - 58th Annual Meeting (12-13 March 2009)
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Prouty, W. F., 1952, Carolina Bays and their Origin, Geological Society of America Bulletin vol. 63,
no. 2, pp. 167–224.
Rieck, R.L. and H. A. Winters, 1982, Characteristics of a Glacially Buried Cuesta in Southeast
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Schultz, P.H., Impact Cratering In Soft Sediment Layers, 2007, Workshop on Impact Cratering II
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Schulte,P.H., et al , 2010, The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-
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Paleogene Boundary, Science, 5 March 2010: Vol. 327. no. 5970, pp. 1214 – 1218, DOI:
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Schultz, P. H. and A. M. Stickle, 2009, Lost Impact, AGU Fall Meeting 2009, Presentation ID#
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Siddall, M., E. J. Rohling, W. G. Thompson, and C. Waelbroeck, 2008, Marine isotope stage 3 sealevel
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615
7 Figures and Attachments
616
Figure 1 - Carolina Bays, Robeson County, North Carolina, USA
617
The color shading of this LiDAR image demonstrates one of the most commonly overlooked
618
characteristics of the bays: they were formed continuously across the pre-existing terrain, and the
619
planforms exhibit no differential based on emplacement elevation. The above view covers 680 km2,
30
620
and includes elevations from 16 m (lower right) to 76 m (upper left). HSV-shader DEM derived from
621
USGS National Elevation Database 1/9 arc-sec, processed in Global Mapper V11.
622
Figure 2– Physical Fractal Distribution of Bubbles in Foam
623
This photograph presents the physical fractal distribution of sizes and locations across field of bubbles.
624
The photo was edited to create the elongation we propose to be a deposition artifact of lateral
625
momentum in the ejecta wave.
626
Figure 3– Cross-section View of Crater
627
An oblique strike into a thick continental ice sheet over the proposed Saginaw region would first excise
628
1 to 2 km of ice before penetrating into terrestrial sedimentary layers. Local ejecta were deposited on
629
the ice sheet, allowing for eventual distribution as common glacial till.
630
Figure 4 – Saginaw Crater Symmetry
631
Lower Michigan DEM with overlay of proposed Saginaw crater extent.
632
Figure 5 – Identifying Carolina bay Orientations
633
Clay County, NE area color ramp LiDAR map using USGS-NED 1/3 arc-sec datum prepared. Shown
634
are numerous paleobasins similar to eastern Carolina bays. The arrow overlay shown allows for
635
assigning an arrival bearing, as interpreted by the user.
636
Figure 6 – Bearing Prediction Trigonometry
637
Uses metrics of Wagram, NC. At time of atmospheric re-entry into a 165-km/hr W➔E “tail wind” the
638
ejecta’s trajectory will be altered. In the prediction case the velocity difference was additive to the
639
W➔E velocity, and thus the model adds the value in; the inversion process (used to drive the
31
640
triangulation network) subtracts the value out. Since the N➔S velocity is constant, the final alignment
641
rotates accordingly. While the ejecta velocity has a vertical component, only ground-plane vectors are
642
considered.
643
Figure 7 – Distribution of Carolina Bays Around Saginaw Crater
644
A) Demonstrates geospatial symmetry around the proposed Saginaw crater. Glacial ice prohibits bay
645
formations to the north. Areas along the impactor’s arrival azimuth were in the “blow-out” zone, where
646
we expect less ejecta and the terrain is rough. B) Vertical axis displays distance in km. Horizontal axis
647
displays state names of the bay fields, ordered clockwise from NJ.
648
Figure 8- Correlation of Predicted Bay Orientations to Measured
649
Plots of the model’s predicted arrival bearing for each field, assuming its components had been ejected
650
from the crater’s centroid (green line), against the measured orientation at that field (blue line). The
651
purple and red lines represent bearing predictions for ejecta lofted from the northeast and southwest
652
ramparts of the crater, and are effectively control bounds for the orientations expected from a
653
geographically expansive crater. Vertical axis displays the arrival bearing in degrees. Horizontal axis
654
displays the state names of the bay fields, ordered clockwise from New Jersey.
655
Figure 9 – Sensitivity Graph of Model Variables
656
Heuristic testing across possible variable values was performed to identify satisfactory solutions to bay
657
alignments using the model. We have defaulted the on-line Bearing Calculator based on parameters
658
yielding an average ground-based velocity vector of 3 km/sec.
659
Figure 10– Comparison of Parabolic Dunes and Carolina bays
32
660
In several locations we have identified Carolina bay ovoid planforms being overridden by true
661
parabolic dune systems. The LiDAR image demonstrates the significant differences between the two
662
planforms, suggesting that entirely different mechanisms are responsible.
663
Supplemental File A: Field Listing with loft distance in km and coordinates.
664
Supplemental File B: Large-format version of the prediction correlation chart, showing ~ 50% of
665
the individual field names.
666
Supplemental File C: KMZ file containing Index for Carolina bay Fields and Saginaw Crater
667
668
http://cintos.org/ge/SaginawKML/WebPlugIn_Summary.kmz
Supplemental File D: Analytical Model Java Code. Plain-text listing of model’s code.
33