EOLIAN-AQUATIC DEPOSITS AND FAUNAS OF THE MIDDLE CAMBRIAN POTSDAM GROUP
2011; Society for Sedimentary Geology; Volume: 26; Issue: 5 Linguagem: Inglês
10.2110/palo.2010.p10-061r
ISSN1938-5323
AutoresJames W. Hagadorn, Joseph H. Collette, Edward S. Belt,
Tópico(s)Paleontology and Stratigraphy of Fossils
ResumoAbstract Exposures of the middle Cambrian Potsdam Group of northern New York, including the type section, represent a suite of interfingering eolian dune and aquatic deposits that record the activities of early land-going arthropods. Quartz arenites at these exposures are dominantly fine to medium grained, well sorted, and have hematite-coated well-rounded, high-sphericity quartz grains characterized by secondary optically continuous quartz cement overgrowths. Eolian beds are laminated and dominated by m- to dm-scale foresets characterized by large-scale, laterally extensive cross-beds that dip >∼15°–34° and contain reverse-graded lamination, en-echelon microfaulted slumps, adhesion structures, and very high ripple-index asymmetric ripples that lie on the foresets with crests that trend downdip. Lower parts of foresets are interpreted as toesets, and contain unusual Diplichnites and Protichnites trackways, which record the uphill, downhill, crest-parallel, and switchback-style movement of arthropods in dr...
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