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Published May 1995 | public
Journal Article

Integrated approaches to terminal Proterozoic stratigraphy: an example from the Olenek Uplift, northeastern Siberia

Abstract

In the Olenek Uplift of northeastern Siberia, the Khorbusuonka Group and overlying Kessyusa and Erkeket formations preserve a significant record of terminal Proterozoic and basal Cambrian Earth history. A composite section more than 350 m thick is reconstructed from numerous exposures along the Khorbusuonka River. The Khorbusuonka Group comprises three principal sedimentary sequences: peritidal dolomites of the Mastakh Formation, which are bounded above and below by red beds; the Khatyspyt and most of the overlying Turkut formations, which shallow upward from relatively deep-water carbonaceous micrites to cross-bedded dolomitic grainstones and stromatolites; and a thin upper Turkut sequence bounded by karst surfaces. The overlying Kessyusa Formation is bounded above and below by erosional surfaces and contains additional parasequence boundaries internally. Ediacaran metazoans, simple trace fossils, and vendotaenids occur in the Khatyspyt Formation; small shelly fossils, more complex trace fossils, and acritarchs all appear near the base of the Kessyusa Formation and diversify upward. The carbon-isotopic composition of carbonates varies stratigraphically in a pattern comparable to that determined for other terminal Proterozoic and basal Cambrian successions. In concert, litho-, bio-, and chemostratigraphic data indicate the importance of the Khorbusuonka Group in the global correlation of terminal Proterozoic sedimentary rocks. Stratigraphic data and a recently determined radiometric date on basal Kessyusa volcanic breccias further underscore the significance of the Olenek region in investigations of the Proterozoic-Cambrian boundary.

Additional Information

© 1995 Elsevier Science B.V. Received 27 May, 1993; revised version accepted 17 December 1993. We thank M. Fedonkin for suggesting and helping to arrange our collaborative field expedition along the Khorbusuonka River. We also thank R. Pflaum for assistance in the analysis of samples, S. Pelechaty and S. Jacobsen for helpful discussions, and M. Walter and G. Narbonne for helpful criticisms of the manuscript. Supported in part by NASA Grant NAGW-893 (to AHK) and EAR-9058199 (to JPG). Elemental analyses supported by NSF Grant EAR-9118628 to S. Jacobsen.

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023