Late Devonian lonestones, diamictites, and coeval black shales from the Appalachian Basin: Discerning relationships and implications for Late Devonian Appalachian history and glacially driven seafloor anoxia

Frank R. Ettensohn, Geoff Clayton, R. Thomas Lierman, Charles E. Mason, Federico F. Krause, Christopher DeBuhr, Thomas B. Brackman, Eric D. Anderson, Allen J. Dennis, Jack C. Pashin

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

A 3 ton (2.7 metric tonnes [t]), granitoid lonestone with Appalachian provenance was found in situ in offshore Devonian black shale in northeastern Kentucky, United States, and is denoted herein as the Robinson boulder, or lonestone, after its discoverer, Michael J. Robinson. This large boulder appears to have been displaced nearly 500 km from its source on the opposite margin of the Acadian/Neoacadian Appalachian foreland basin. While previous identifications of possible lonestones have been attributed to Pleistocene glacial events, scrutiny of this lonestone's origin suggests that the boulder, which was embedded in the Upper Devonian Cleveland Shale Member of the Ohio Shale in northeastern Kentucky, is most likely a Devonian ice-rafted glacial dropstone. Notably, palynologic correlation with reported glacial diamictites elsewhere in the basin indicates such a source. Together, the dropstone and diamictites, separated by ~500 km, provide evidence for alpine glaciation in the ancient Acadian/Neoacadian orogen and for tidewater glaciers in the adjacent, eastern margin of the foreland basin. The latest Devonian marine transgression and Neoacadian foreland subsidence are interpreted to have been associated with tidewater glacial connections to the open sea. Importantly, the existence of this dropstone and its likely glacial precursor events require new considerations about contemporary black-shale sedimentation and the influence of tectonics on the delivery of glacial sediments to foreland basins.

Original languageEnglish
Pages (from-to)67-88
Number of pages22
JournalSpecial Paper of the Geological Society of America
Volume545
DOIs
StatePublished - Aug 12 2020

Bibliographical note

Publisher Copyright:
© 2020 The Geological Society of America. All rights reserved.

ASJC Scopus subject areas

  • Geology

Fingerprint

Dive into the research topics of 'Late Devonian lonestones, diamictites, and coeval black shales from the Appalachian Basin: Discerning relationships and implications for Late Devonian Appalachian history and glacially driven seafloor anoxia'. Together they form a unique fingerprint.

Cite this