Organic-Walled Microfossils from Earliest Cambrian or Latest Proterozoic Tindir Group Rocks, Northwest Canada
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چکیده
Allison, C.W. and Awramik, S.M., 1989. Organic-walled microfossils from earliest Cambrian or latest Proterozoic Tindir Group rocks, northwest Canada. Precambrian Res., 43: 253-294. Uppermost Tindir Group limestones exposed in the headwaters of Tindir Creek, Yukon Territory, Canada, contain a diverse and abundant microbiota of mineralized and organic-walled microfossils. Preserved primarily in chert nodules and chert beds, the organic-walled forms include mat-building cyanobacterial filaments and coccoids accompanied by less common bacteria, fungi and forms of uncertain affinity as well as planktonic coccoidal cyanobacteria and acritarchs. Several lines of evidence support interpretation of an Early Cambrian age whereas others suggest a Late Proterozoic age. Of the 54 organic-walled taxa recognized, 12 are newly described: Yukonosphaeridion interior Awramik, n. gen., n. sp., Microagglomeratus borealis Awramik n. gen., n. sp., Phacelogeminus lineatus Awramik n. gen., n. sp., Palaeoanacystis magna Awramik, n. sp., Cephalophytarion majesticum Allison n. sp., Heliconema bulbosa Allison n. sp., Trachyhystrichosphaera magna Allison n. sp., FusilabeUum brevistriatum Awramik n. gen., n. sp., Sphaeranasillos irregularis Allison n. gen., n. sp., Hyalocyrillium clardyi Allison n. gen., n. sp., Eophycomyces herkoides Allison n. gen., n. sp. and Archeomyces dimakeloides Allison n. gen., n. sp.
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