The Pennsylvanian Springhill Mines Formation: sedimentological framework for a portion of the Joggins Fossil Cliffs UNESCO World Heritage Site

Atlantic Geology

Matthew R. Stimson²  Kyle T. Ashley¹  Erin P. Sheldon¹  John H. Calder³  Michael C. Rygel¹  Jamie L. Salg¹ 

[1] Department of GeologyState University of New York, College at Potsdam44 Pierrepont Ave.Potsdam, NY 13676 USA;Department of GeologySaint Mary’s University, 923 Robie St.Halifax, Nova Scotia, B3H 3C3, Canada;Nova Scotia Department of Natural ResourcesP.O. Box 698Halifax, Nova Scotia, B3J 2T9, Canada

关键词: Sedimentology;    Stratigraphy;    Paleontology;   

DOI  :  

学科分类：地质学

来源: Atlantic Geoscience Society

【 摘 要 】

This is the first detailed study of the coastal exposure of the Springhill Mines Formation within the Joggins Fossil Cliffs World Heritage Site. A 16.9-m-thick interval of dark laminated mudrocks and sharpbased sandstones at the base of our section is reassigned to the top of the Joggins Formation. This interval records a rapid, presumably widespread flooding event and the temporary establishment of a marginalmarine to brackish bay. The overlying 697 m of strata represent deposition in poorly drained and well-drained environments, and are assigned to the Springhill Mines Formation. Strata reflecting poorly drained environments contain green and grey mudrocks, thin coals, sheet sandstones, and channel bodies interpreted to have been deposited in coastal swamps and low-lying parts of a floodplain. Intervals reflecting well-drained conditions contain reddish brown mudrocks, sheet sandstones, and channel bodies interpreted to have been deposited on a vegetated floodplain that was periodically exposed to oxidizing conditions. Strata reflecting poorly drained conditions are thick and abundant in the lower half of the formation and well-drained intervals become thick and more abundant in the upper half. The shift in facies abundance is accompanied by an interpreted evolution in fluvial style from predominantly anastomosed channels (below 376 m) to sheet-like channel bodies (376–449 m) and ultimately to predominantly meandering-channel bodies (449–697 m). The formation-scale changes in drainage conditions and fluvial style records decreased halokinetic subsidence and aggradation of the alluvial surface as sediments shed from the Caledonia Highlands prograded into this part of the basin.

【 授权许可】

Unknown