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Barbados Ridge; Inner Trench Slope Sedimentation, William J. Cleary, H. Allen Curran, Paul A. Thayer

Geosciences: Faculty Publications

Quaternary sediments of this inner trench slope are chiefly foraminiferal-pteropod-nanno oozes that have been reworked and/or emplaced by gravity currents. These oozes are mixed with volcanogenic sediments and minor amounts of material derived from the insular shelf. Reworking occurs on topographic highs where fines are winnowed out and mass wasting and gravity currents are initiated; these processes ultimately result in the leveling of irregular floors of deeper, intervening slope basins. Petrographic analyses of graded intervals from the basin floors and slopes reveal the sands to be mixtures of planktic foraminifers (35%), pteropods (10%), and fresh, angular volcanic detritus (10-90%). On …

Ichnology Of Pleistocene Carbonates On San Salvador, Bahamas, H. Allen Curran

Geosciences: Faculty Publications

ABSTRACT-Trace fossils, well preserved and in full relief, are present in Pleistocene calcarenites of subtidal, beach, and dune facies on San Salvador, Bahamas. Most prominent are irregular boxworks of Ophiomorpha sp. that occur in current-bedded, medium to coarse skeletal calcarenites in association with fossil coral reefs in the subtidal facies. Ophiomorpha sp. also occurs in beds deposited in a tidal delta environment. Found with Ophiomorpha sp., often in abundance, are vertical burrow tubes assigned to Skolithos linearis. Trace fossils are absent from beds of the lower beach facies, but upper beach facies beds (backshore zone) contain distinctive Y-shaped crab …

Tracemaking Activities Of Crabs And Their Environmental Significance: The Ichnogenus Psilonichnus, Robert W. Frey, H. Allen Curran, S. George Pemberton

Geosciences: Faculty Publications

Modem crabs are common inhabitants of shallow subtidal, intertidal, and supratidal environments, and many crabs are capable of producing traces that can be preserved in the rock record. The first crabs, Early Jurassic in age, probably were not fossorial. By Cretaceous time, however, diverse endobenthic lineages were established. Many representatives of these lineages undoubtedly produced domiciles that are preserved in shallow marine to quasimarine sediments and that should be useful in characterizing the depositional environment of the sediments. Nonetheless, most such dwelling structures have been studied little and remain essentially unnamed.

The ichnogenus Psilonichnus Fiirsich is amenable to the taxonomic …

Field Guide To The Cockburn Town Fossil Coral Reef, San Salvador, Bahamas, H. Allen Curran, Brian White

Geosciences: Faculty Publications

James W. Teeter (ed.), 1984, Proceedings of the 2nd Symposium on the Geology of the Bahamas:San Salvador, CCFL Bahamian Field Station

A Shallowing-Upward Sequence In A Pleistocene Coral Reef And Associated Facies, San Salvador, Bahamas, Brian White, Karen J. Kurkjy, H. Allen Curran

Geosciences: Faculty Publications

The Sangamon-age Cockburn Town fossil coral reef complex displays a vertical sequence of facies from coral reef and closely associated subtidal carbonate sands, through beach calcarenites, to eolianites. This upward change reflects a progressive lowering of sea level and the eventual emergence of the reef complex into a subaerial environment. The contact between upper beach sediments and eolianites is at +4 m providing a minimum for the sea level high stand. Essentially in situ Acropora palmata suggests a sea level of at least 5 to 6 m above present. These values are similar to Sangamon-age high stands reported from New …