Publication Date:
2016-01-01
Description:
Lower Silurian conodonts were recovered from carbonate beds in the upper Zalaa and lower Sharchuluut formations at Yamaan Us in the Shine Jinst region, Gobi-Altai Zone, of southwestern Mongolia. Conodonts are described from the Zalaa Formation for the first time; key taxa recovered includeDistomodus kentuckyensisBranson and Branson, 1947,Ozarkodina hassi(Pollock, Rexroad, and Nicoll, 1970), Pranognathus siluricus(Pollock, Rexroad, and Nicoll, 1970), andPseudolonchodina expansa(Armstrong, 1990). These species constrain the onset of the Silurian carbonate platform, upper Zalaa to lower Sharchuluut formations, to thePranognathus tenuisZone, middle Aeronian. The presence of a cosmopolitan conodont fauna places these strata from the Gobi-Altai Zone in a basin-shelf marine setting with connection and circulation to the open ocean during the Llandovery.
Print ISSN:
0022-3360
Electronic ISSN:
1937-2337
Topics:
Geosciences
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