Pliocene-Holocene evolution of depositional conditions in the eastern Mediterranean; role of anoxia vs. productivity at time of sapropel deposition

Online Access: Get full text
doi: 10.1016/j.palaeo.2006.10.008
Author(s): Gallego-Torres, David; Martínez-Ruiz, Francisca; Paytan, A.; Jiménez-Espejo, Francisco J.; Ortega-Huertas, M.
Author Affiliation(s): Primary:
CSIC-Universidad de Granada, Instituto Andaluz de Ciencias de la Tierra, Granada, Spain
Stanford University, United States
Volume Title: Palaeogeography, Palaeoclimatology, Palaeoecology
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, 246(2-4), p.424-439. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. With appendix available online. 94 refs.; illus., incl. 2 tables, sketch map
Summary: A multiproxy geochemical study of nine sapropel layers from ODP Hole 964A, ODP Leg 160 in the eastern Mediterranean spanning the Pliocene-Holocene time interval provides new insights into the evolution of sapropel deposition. Paleoenvironmental proxies were used for reconstruction of productivity (Ba derived from marine barite), oxygen conditions (trace metal ratios) and sedimentary regime (clay minerals, detrital elements). These proxies reveal a significant increase in river runoff relative to decreasing aeolian input during sapropel deposition over the whole time interval. Ba excess supports the argument that a significant increase in export productivity is the main triggering mechanism for sapropel deposition, although preservation also played an important role. Furthermore, major differences exist in depositional conditions, including both oxygenation and productivity since the Pliocene. Productivity fluctuated substantially and was higher during the Pliocene and Pleistocene than during the Holocene; at the same time decreasing oxygen availability parallels the enhanced productivity. Dysoxic to anoxic conditions appear to coincide with marine productivity maxima, thus suggesting that oxygen depletion may be linked to greater consumption rather than restricted circulation. This correspondence supports the hypothesis that productivity fluctuations resulting from climate oscillations were the main cause of enhanced organic matter contents and also a main controlling factor for reduced oxygen availability. Abstract Copyright (2007) Elsevier, B.V.
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Anaerobic environment; Cenozoic; Clay mineralogy; Climate change; Depositional environment; Detritus; East Mediterranean; Eh; Geochemistry; Leg 160; Marine environment; Marine sediments; Mediterranean Sea; Neogene; ODP Site 964; Ocean Drilling Program; Organic compounds; Oxygen; Paleo-oceanography; Paleoclimatology; Paleoecology; Pelagic environment; Pliocene; Productivity; Quaternary; Sapropel; Sedimentation; Sedimentation rates; Sediments; Tertiary
Coordinates: N361538 N361538 E0174500 E0174500
Record ID: 2007047275
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands