Reconnaissance investigation of the Lisburne Group in the Cobblestone Creek area, Chandler Lake quadrangle, Alaska

Alaska Division of Geological & Geophysical Surveys Preliminary Interpretive Report 2015-2
By:  and 
Edited by: M. A. Wartes and P. L. Decker

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Abstract

A reconnaissance investigation of the Carboniferous Lisburne Group in the Cobblestone Creek area, Chandler Lake Quadrangle, yields insights into its resource potential and regional relations. Locally porous vuggy dolostone with hydrocarbon reservoir potential occurs in the lower Lisburne in the three most southerly of five thrust sheets, and contains traces of dead oil in two of these sheets. The dolostones are coarse crystalline, commonly cross-bedded, and at least in part of Osagean (late Early Mississippian) age; they have pelmatozoan grainstone protoliths that likely formed in sand shoals of the midramp to inner ramp. Similar, coeval porous dolostones occur in the Lisburne from Skimo Creek to Itkillik Lake, ~70 km west and 10 km east of the Cobblestone Creek area, respectively. We also examined the uppermost Lisburne Group at several localities in the Cobblestone Creek area, mainly in the northernmost thrust sheet where the rocks are as young as Morrowan (Early Pennsylvanian). Cobblestone sections contain more supportstone than equivalent strata at Skimo Creek, and overlying Permian successions also differ between the two areas. These lithologic contrasts may reflect different rates of tectonically controlled subsidence, and (or) changes in sediment input, along the late Paleozoic continental margin.

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Additional publication details

Publication type Report
Publication Subtype State/Local Government Series
Title Reconnaissance investigation of the Lisburne Group in the Cobblestone Creek area, Chandler Lake quadrangle, Alaska
Series title Alaska Division of Geological & Geophysical Surveys Preliminary Interpretive Report
Series number 2015-2
DOI 10.14509/29403
Year Published 2015
Language English
Contributing office(s) Alaska Science Center Geology Minerals
Description 17 p.
Country United States
State Alaska
Other Geospatial Chandler Lake Quadrangle
Online Only (Y/N) N
Additional Online Files (Y/N) N
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