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Unformatted text preview: 1 MAS 603: Geological Oceanography MAS 603: Geological Oceanography Lecture 12: Sedimentary Facies (Beaches) UNIVERSITY OF SOUTH ALABAMA UNIVERSITY OF SOUTH ALABAMA Last time we covered Proterozoic Evolution Discussion (Isabella) Proterozoic Beasties 1) Eukaryotes (Acritarchs) 2) Metazoans (Ediacarin Fauna) 3) A visit to the Burgess Shale Proterozoic Fossils The first eukaryotes appeared around 2 GA. Archritarchs were small, single celled silica beasties that floated in the oceans (pelagic). They peaked in abundance at 750 MA and then went away 0.1mm Proterozoic Fossils Another big change in the Proterozoic was the appearance of the first Metazoans 5 cm Proterozoic Fossils ht p:/ www.snowbal earth.org/end.html The Cambrian Explosion ht p:/ arjournals.annualreviews.org/na101/home/literatum/publisher/ What we know about the early development of all of the current phyla is limited to sites where we have lots of beasties preserved Burgess Shale Fauna Chengjiang Fauna 2 ht p:/ home.earthlink.net/~airdpacoima/sitebuildercontent/sitebuilderpictures/burgess__s.jpg The Burgess Shale Today Today s Agenda s Agenda Sedimentary Facies 1) Facies versus depositional environments 2) Walthers Law 3) Beaches Sedimentary Facies There are literally dozens of different depositional environments that cover every imaginable marine and non-marine situation. ht p:/ earthsci.org/mineral/rockmin/sed/clastics.gif Sedimentary Facies For example, rivers come in at least 3 flavors: 1) Meandering 2) Braided 3) Anastimosing And in most cases, there are multiple varieties of each basic environment of deposition. Sedimentary Facies Ultimately, depositional environments are the sum of their various components and each of those components are distinguished from one another of the basis of geological characteristics....
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- Fall '11