Open AccessSedimentology, biostratinomy, and palaeoecology of an Upper Jurassic offshore sand bar complex
Author(s) -
Franz T. Fürsich,
Claus Heinberg
Publication year - 1983
Publication title -
bulletin of the geological society of denmark
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.674
H-Index - 28
eISSN - 2245-7070
pISSN - 0011-6297
DOI - 10.37570/bgsd-1983-32-04
Subject(s) - geology , sedimentology , palaeogeography , shoal , paleontology , submarine pipeline , sedimentary rock , sedimentary structures , paleoecology , mouth bar , shore , sediment , winnowing , sedimentary depositional environment , geomorphology , structural basin , oceanography , tectonics , archaeology , volcanism , history
The Aldinger Elv Member (Upper Oxfordian) of Milne Land, East Greenland, is a wedge-shaped sand body up to 90 m thick, intercalated between silty shales. The combination of sedimentological, biostratinomic and palaeoecological data allows a detailed reconstruction of the morphology, genesis, and palaeogeography of the bar complex. Sedimentary structures, macrobenthos and trace fossils exhibit a zonation across the sand body. The well-sorted fine-grained sands exhibit sedimentary structures, bioturbation and numerous shell beds. Three macrobenthic associations and four ichnocoenoses are distinguished. The former occur in situ as well as in various stages of reworking. Convex-upward shell pavements were formed by currents, while unsorted shell beds were generated by storms. The sand wedge is interpreted as a shallow offshore sand complex separated from the shore by a broad swale and supplied with sediment from the north along a shoal which extended southwards, while the coastline was deflected in a southwesterly direction by a slow transgression.