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Trace fossils as a paleoceanographic tool: evidence from Late Quaternary sediments of the southwestern Iberian margin

Authors :
Friedrich Werner
Ludvig Löwemark
Priska Schäfer
Joachim Schönfeld
Source :
Marine Geology. 204:27-41
Publication Year :
2004
Publisher :
Elsevier BV, 2004.

Abstract

Biogenic structures in Late Quaternary sediments from the southwestern Iberian continental slope were studied by using X-ray images from two cores from 580 and 1750 m water depth. Eight different ichnocoenoses were observed: indistinct bioturbation, Planolites-dominated, Thalassinoides-dominated, Chondrites-dominated, Planolites and Thalassinoides-dominated, pyritized microburrows such as Trichichnus and ‘Mycellia’-dominated, Chondrites, Trichichnus, and ‘Mycellia’-dominated and Zoophycos. Variations of the ichnocoenoses within the cores show a striking correlation with climatically induced changes in the hydrographical regime, i.e. current strength and bathymetric position of the Mediterranean Outflow Water (MOW). Comparison of the response of the ichnocoenoses to changes in bottom-water conditions and substrate between the two cores studied indicate that bottom-water oxygenation and enrichment of particulate organic matter at the base of the MOW layer are the primary factors controlling the ichnocoenoses. The traces even recorded short-term climatic changes such as the Younger Dryas cold event. The spatial and temporal distribution patterns are in good agreement with earlier models of the MOW history, which gives reason to see a refinement of trace fossils as a complementary tool for paleoceanographical studies.

Details

ISSN :
00253227
Volume :
204
Database :
OpenAIRE
Journal :
Marine Geology
Accession number :
edsair.doi...........7bd9d3d5e1d7e48c701fd1034bb4b441
Full Text :
https://doi.org/10.1016/s0025-3227(03)00351-7