The Aaron Formation in North Central, North Carolina: Contact Relationships and Regional
Significance.
Clearly state the problem(s) to be addressed, the hypothesis or hypotheses to be tested, and the
overall objectives of your proposed project. (1,200 character limit):
The objectives of the study are to (1) determine the nature of the contact between the
Precambrian Hyco and Aaron formations in the Carolina terrane of the Southeast Appalachians,
(2) constrain the age of the Aaron formation by age dating the interlayered Virgilina volcanics
and (3) determine the Nd-isotopic characteristics of the Virgilina volcanics. The Aaron formation
has been previously thought to conformably overly the Hyco formation (Laney 1917, Glover and
Sinha 1973, and Kreisa 1980). However, recent geochronological data indicate a major time gap
in the sequence between units. Magmatic rocks of the Hyco formation have been dated at c.
619.9 to 615.7 Ma (Wortman et al. 2000) and the Aaron formation contains detrital zircons as
young as c. 578 Ma (Samson et. al. 2001, Pollock 2007). Therefore the Aaron formation along
with the interlayered Virgilina volcanics must be significantly younger than the Hyco formation.
U-Pb zircon dating of the Virgilina volcanics will help constrain the age of the Aaron formation.
Nd-isotopic study of both units will allow for a comparison with other Carolina terrane arc
sequences.
Discuss the previous work on your problem(s) that (1) places the project in a disciplinary and, if
appropriate, regional context and (2) documents the importance of your project. (2,500
character limit):
Previous geologists (Laney, 1917; Glover and Sinha, 1973; Kreisa, 1980) all produced
regional maps of the Virgilina District of Virginia and North Carolina and indicated that the Hyco
and Aaron formation along with the Virgilina volcanics form a conformable stratigraphic
sequence. These previous workers did not specifically describe the contact relationships
between the units. This apparently conformable sequence has been used favorably in
correlating the Carolina terrane with the Northern Appalachian Avalon terrane (Williams and
Hatcher 1983), the two largest exotic terrane blocks in the Appalachian orogen. More recently
however, on the basis of other geologic characteristics, this correlation has been questioned
(Secor et. al. 1983, Hibbard et. al. 2002, 2007). Recent geochronology indicates a significant
time gap between the Hyco and Aaron formations. If the contact is discovered to be an angular
unconformity, it would suggest that a significant deformational event took place in the Carolina
terrane that is not recorded in the Avalon terrane. This would favorably support the noncorrelation of the Carolina terrane with the Avalon terrane. In addition to the U-Pb zircon age
dating of the Virgilina volcanics, the Nd-isotopic analysis of the Aaron formation and Virgilina
volcanics should allow me to determine if these units are related to the older Hyco arc or if they
are linked to a younger Carolina terrane arc sequence, the Albemarle arc.
Concisely state how you plan to address your problem(s) and test your hypothesis or hypotheses
(2,500 character limit):
In order to attain my objectives, I will undertake field and lab studies. My first step will be
unprecedented detailed geologic mapping of the contacts between the units mentioned above.
I will traverse the contacts and pay particular attention to the concordancy/discordancy of beds
and presence or absence of fault products. Once the contact of the two units has been found
and mapped, the nature of the contact can be deduced from the observations. The field
mapping will also identify fresh outcrops of the Virgilina volcanics which are suitable for U-Pb
zircon dating. In addition to the dating, Nd isotopic work will also be carried out in order to
compare the Virgilina volcanics with both older (Hyco formation) and younger arc rocks of the
Carolina terrane. I will be collaborating with Dr. Brent Miller of Texas A&M University for my
Nd-isotopic analysis and with his new U-Pb geochronology laboratory.
In summary, my work is directed at determining the nature of the contact, such as any
angular unconformity that may have recorded a major deformational event. Also, my work will
determine the age and Nd-isotopic characteristics of the Aaron formation and Virgilina
volcanics to compare with other exotic Appalachian arc rocks. The findings from this project
will provide further data toward determining the relationship between the Carolina and the
Avalon terranes.
Duration of investigation (dates):
January 2008 – December 2009
Budget justification (1,200 character limit):
U-Pb Zircon Age Dating ..……………………………………………………………………………….. $ 900.00
U-Pb zircon age date of Virgilina volcanics,
1 age date @ $900.00
Isotopic Analysis ..………………………………………………………………………………………….. $ 750.00
Nd-isotopic analysis,
5 analysis @ $150.00 each
Lodging ………………………………………………………………………………………………………….. $ 500.00
Camping fees, county park available near field area,
$50.00/week (10 weeks)
Thin sections ………………………………………………………………………………………………….. $ 600.00
40 @ $15.00 each
Topographic Maps ..……………………………………………………………………………………….. $ 24.00
6 maps @ $4.00 each
Food ………………………………………………………………………………………………………………. $ 1400.00
Food per diem,
$20.00/day (70 days)
Travel ……………………………………………………………………………………………………………. $ 534.00
To and from the field area once or twice a week,
Roundtrip ~ 120 mi., $0.445/mile (~ 1200 mi)
Total ……………………………….………………………………………………………………………………. $ 4708.00
Amount and nature of other available funds, facilities, materials, etc. (1,200 character limit):
Limited funds from a National Science Foundation grant awarded to Dr. Jim Hibbard that is
almost fully expended will cover $2,000.00 of my food and travel expenses.
Abbreviated resume. List education, major positions held, and significant accomplishments.
Provide information relevant to your qualifications to undertake proposed research. List up to 5
of your publications and presentations (2,500 character limit):
Education:
1/9/2008 - Present
2003 – 2007
North Carolina State University, Raleigh, NC 27606
Masters Candidate in Geological Sciences
Indiana University, Bloomington, IN 47403
Bachelor of Science – Geological Sciences
Geology GPA: 3.91/4.0 Overall GPA: 3.11/4.0
Skills:
Scientific lab and field work experience, Geologic mapping and Geochemical Analysis
Employment:
Park Ranger, Black Canyon of Gunnison National Park, Gunnison, CO
September 2007 – November 2007
Environmental education programs, k-12
Assistant Instructor, Judson Meade Indiana University Geologic Field Station, Cardwell, MT
June 2007 – August 2007
Help students in the field with a variety of mapping exercises
Field Technician, Indiana Geological Survey, Bloomington, IN
May – August 2005
Worked independently collecting well data, Gamma Log
Program Assistant, Wonderlab Science Museum , Bloomington, IN
Honors Internship 2004 – 2007
Facilitate & develop programs for kids
Research and develop new activities
Assist in development of geology demo
Projects:
Extensive structural and geologic mapping of Southwest Montana, Indiana University Geologic Field
Station.
Undergrad Senior Project – sample collection, geochemical analysis, and poster
Publication:
Bowman, Jeffrey D., 2007. Asthenospheric Upwelling and Slab Roll-Back of the Subducting Avalon
Plate: Geochemical Evidence from the Lebanon Gabbro, East-Central Connecticut, GSA Abstracts
with Programs Vol. 39, No. 1, p. 76
Accomplishments:
Co-Founder & Vice President IU Geology Club, Undergraduate Representative for department Student
Advisory Committee, Raised over $900 for IU Geology Club, Published abstract for NE Geological Society
of America conference as an undergraduate
References cited in proposal (2,500 character limit):
Glover, Lynn, III, and Sinha, A. K., 1973, The Virgilina deformation, a late Precambrian to Early
Cambrian(?) orogenic event in the central Piedmont of Virginia and North Carolina:
American Journal of Science, v. 273-A, p. 234-251
Hibbard, J., Stoddard, E., Secor, D., and Dennis, A., 2002, The Carolina Zone: overview of
Neoproterozoic to early Paleozoic peri-Gondwanan terranes along with eastern flank of
the southern Appalachian: Earth Science Reviews, v. 57, p. 299-339.
Hibbard, J. P., van Staal, C. R., and Miller, B. V., 2007, Links between Carolina, Avalonia, and
Ganderia in the Appalachian per-Gondwanan realm: Geological Survey of Canada Map
02096A, 2 sheets, scale 1:1,500,000.
Kreisa, R. D., 1980. Geology of the Omega, South Boston, Cluster Springs, and Virgilina
quadrangles, Virginia. Va. Div. Miner. Resour. Publ. 5, 22 p.
Laney, F. B., 1917, The geology and ore deposits of the Virgilina District of Virginia and North
Carolina: Virginia Geol. Survey Bull. 14, 176 p.; also pub. As North Carolina Geol. And
Econ. Survey Bull. 26.
Pollock, J. C., 2007, Depositional and tectonic setting of the Neoproterozoic early Paleozoic
rocks of Carolina: Evolution of volcanic arc-related sedimentary sequences based on UPb detrital zircon geochronology. PHD Dissertation, North Carolina State University,
Raleigh, NC, 194 p.
Samson, Scott D., Secor, D. T., 2001, Wandering Carolina: Tracking exotic terranes with detrital
Zircons, GSA Abstracts with Programs Vol. 33, No. 6, p. A-263
Secor, D., Samson, S. L., Snoke, A. W.; and Palmer, A. R. 1983. Confirmation of the Carolina slate
belt as an exotic terrane. Science 221:649-651.
Williams, H. and Hatcher, R.D., Jr., 1983, Appalachian suspect terranes, in Hatcher, R.D., Jr.,
Williams, H. and Zietz, I., eds., Contributions to the Tectonics and Geophysics of
Mountain Chains: Geological Society of America, Memoir 158, p. 33-53.
Wortman, G., Samson, S., Hibbard, J., 2000. Precise U-Pb zircon constraints on the earliest
magmatic history of the Carolina terrane. Journal of Geology 108, 321-338.