How to use this template (DELETE THIS SLIDE) • This is only a guide, you may add to this if you wish. • Do not add pictures as background, to hard to see and looks messy. • Less is more, don’t fill slides with words, add brief bullets and a picture or diagram. You should explain in your talk not have other read your slide. • Your presentation needs to be 5 minutes long so practice and be sure to hit all important points and discussions. • Be sure to cite everything that is not yours!!! 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.