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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 69 (1985)

Issue: 9. (September)

First Page: 1437

Last Page: 1437

Title: Setting of Early Ordovician (Arenigian) Carbonate Sedimentation in Appalachian Basin: Arid Climatic Epicontinental Seas Interrupted by Intermittent Conditions of Emergence: ABSTRACT

Author(s): Gerald M. Friedman

Article Type: Meeting abstract

Abstract:

Epicontinental seas with sea-marginal sabkhas persisted within the tropic zone of what is now the Appalachian basin. The arid climate and hypersaline conditions influenced the accumulation of carbonate sediments. Conditions of intermittent emergence interrupted cycles of carbonate sedimentation.

Evidence of hypersalinity includes calcitic, dolomitic, or siliceous pseudomorphs of former anhydrite nodules; calcite and euhedral quartz infilling solution-enhanced vugs after evaporite nodules; carbonate pseudomorphs after gypsum and halite; euhedral quartz; authigenic K-feldspar; paucity of skeletal debris; preservation of stromatolites; and length-slow chalcedony, including chalcedonic spherulites, half-moon ooids, and dedolomites. Intermittent emergence is inferred from solution-collapse features, desiccation cracks, eroded surfaces, surfaces of induration such as silcrete, and lag concentrates of micrite chips (flat-pebble conglomerate). Angular clasts of dolostone and limestone resulted from collapse and brecciation of overlying strata, when evaporites underlying them dissolve .

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