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Ordovician Carbonates in Northwest
Lewis and Parts of Southeast Jefferson
Counties
Andrews, J
Teacher
Block 1
Purpose Statement
• Using field data collected personally and with
other geologists from 2003 field season.
• “Rework” the complicated naming system that
is defined previously.
Introduction
• Collecting field data (via walking waterways)
• Naming system used incorrectly.
• Rocks in this area were formed underway and
have fossils in the rocks.
Harvard Geology department
Titus 1986 and Isachsen 2000
Methods
• All researchers including myself walked rock
outcrops where ever possible.
• Measurements of the formations made with
Jacobs Staff
• All data recorded, faults, dipping layers and
fauna
Results
• Rock layers were described by Johnsen (1971)
and Walker (1973) based mainly on formation
thickness and fauna.
• Discuss results of methods of research
• Any possible issues with the research?
Discussion
• Formational ID new
• What are your conclusions from your
research?
• What are the results of this research?
• Compare results to you purpose statement
Hillier (Cobourg)
Denley (Denmark)
Mohawkian
Trenton
Middle Ordovician
Steuben (Cobourg)
Lithology
&
Contact Description
Base: See top of Stueben
Ls, mostly Micritic.
Top: Erosional surface
capped by phosphatic rich
beds.
Base: base of criniodal
grainstone that has no
Shale interbeds
Top: Sparry grainstone
grading to micritic
packstone. Contact can
span over 1m.
Average
Thickness (m)
Formation
Series
Group
System
Age
8
Fuana
Hormotoma,
Fusispira,
Conularia
trentonensi,
Rafinesquina
deltoidea
Rafinesquina
deltoidea,
Triarthrus eatoni,
Climacograptus
Trilobites
Triarthrus
8
Base: Shale beds increase
to 5-8cm. Ls increase and
are micritic
Top:
Shale interbeds disappear,
top is defined by last shale
interbed
Cryptolithus,
Paraspora,
Trocholites,
Rafinesquina,
Hormotoma,
Resserela
Cryptolithus
Prasopora
10-50 uncertian
Base: Ls beds decrease to
(5-8cm) and are sparry.
Contact sharp to
Sugar River (Shoreham)
gradational
Top:Defined by Base of
Denley
Kings Falls (Kirkfield)
Napanee (Rockland)
Base: lowest in series of
12-25cm thick beds
contianing para-ripples
Top: Bed thickness
decreases but still variable.
Trocholites,
Cryptolithus,
Prasopora
14-22
14-20
Triplesia,
Sowerbyella,
Cryptolithus pora
orientalis,
Rafinesquina,
Parastrophina
4-16
Doleroides
ottawanus,
Triplesia
cuspidata,
PaucicruraDalmanella
rogata,
Sowerbyella
Base: thin to thick, grey to
brown calcilutites
interbedded with shale,
Basel beds are often
graded (disconformity)
Top: Beds become more
sparry and fosiliferous.
Sowerbyella
Lithology
&
Contact Description
Average Thickness
(m)
Formation
Series
Group
System
Age
6
Mohawkian
Black River
Middle Ordovician
Base:Base of thick to
massive weathering Ls
beds.
Watertown (Chaumont)
Top: Top of a set of thck
to massive weathering Ls
containing Chert nodules
Lowville
Base: Top of Pamelia
Top: Dark grey micritic Ls
containing Gastropods
Pamelia
Base: arkosic
conglomerate or Ss or
Dolostone.
(nonconformity)
Top: where a 3.0m
interval has a
dolostone/Ls ratio of 1:1,
also placed at top of last
dolostone bed.
6-10
Gniess
??
Fuana
(chephalopods)
Actinoceras
tenuifilum,
Endoceras,
Gojioceras,
Tetradium
fibratum
Phytopsis
tubulosa,
Hormotoma sp.
8-18
PreCambrian
Tetradium
syringoporoides,
Brachiopods
Conclusion
• Work done by Kay (1930’s) was correct and
properly cited, thus must be used (ACSN
1982).
• Future research included mapping of faults for
natural gas and the use of radiometric dating.
References
•
American Commission on stratigraphic Nomenclature, 1982,
note1 –Organization and objectives of the Stratigraphic
Commission: American Association of Petroleum Geologists
Bulletin, v. 31, no. 3, p. 513-518.
•
Johnsen, H. J. 1971. The Limestones of Jefferson
County, New York. N.Y. State Museum and science
service. Map and chart series 13.
•
•
Chenoweth, A. P. 1952. Statistical methods Applied to
Trentonian Stratigraphy in New York. Bulletin of the Geological
Society of America. Volume 63, pp. 521-560.
Kay, G. M. 1933. The Ordovician Trenton Group in
Northwestern New York: Stratigraphy of the lower
and upper limestone formations. American Journal
of Science.
•
Cushing, H. P. 1908. Lower portion of the Paleozoic sections in •
northwestern New York. Geological Society of
America. Bulletin 19: 155-176.
Kay, G. M. 1937 Stratigraphy of the Trenton group.
Geological Society of America. Bulletin 48 pp. 233302.
•
Fisher, D. W. 1962. Correlation of the Ordovician rocks of New
York State. New York State museum and science service. Map
and chart series 3.
•
Titus, R. Fossil Communities of the Upper Trenton
Group (Ordovician) of New York State. Journal of
Paleontology. Volume 60, no. 4, pp. 805-824. 1986.
•
Folk, R.L., 1962, Spectral subdivisions of limestone types, in
W.E. Ham (ed.), classification of carbonate rocks: American
Association of Petroleum Geologists Mem. 1 p. 62-84.
•
Walker, K.R. 1973. Stratigraphy and Environmental
Sedimentology of Middle Ordovician Black River
Group in the Type Area- New York State. N.Y. State
Museum and science service. Bulletin 419.
•
Isachsen, W. Y., Landing, E., Lauber, M. J., Rickard, V. L., Rogers,
B. W.. 2000. Geology of New York, A simplified account. Second •
edition. New York State Museum.
Winder, C. G. 1960. Paleoecological interpretation
of Middle Ordovician statigraphy in southern
Onartio, Canada. Ordovician and Silurian
stratigraphy and correlations. Inter. Geol. Cong.,
Copenhagen, Denmark 21: 18-27.