Paleoproductivity during the mid Miocene climate transition

Author(s): Diester-Haass, L.; Billups, K.; Emeis, K. C.
Author Affiliation(s): Primary:
Universitaet des Saarlandes, Zentrum fuer Umweltforschung, Saarbrucken, Federal Republic of Germany
Other:
University of Delaware, United States
Universitaet Hamburg, Federal Republic of Germany
Volume Title: AGU 2006 fall meeting
Source: Eos, Transactions, American Geophysical Union, 87( Fall Meeting Suppl.); American Geophysical Union 2006 fall meeting, San Francisco, CA, Dec. 11-15, 2006. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0096-3941 CODEN: EOSTAJ
Note: In English
Summary: The 16-14 Ma interval of the mid-Miocene is characterized by a period of relative warmth and the highest benthic and planktic foraminiferal δ13C values since the Paleocene. The mid Miocene period of relative warmth is followed by a major step in Antarctic ice sheet expansion at 14 Ma and a shift toward lower foraminiferal δ13C values. Here we investigate the relationship between benthic foraminiferal δ13C values, paleoproductivity, and climate change for a time interval encompassing the mid Miocene (19-11 Ma). We present results from three ODP sites located in the Atlantic Ocean (Sites 608, 925, and 1265). Results indicate that productivity derived from benthic foraminiferal accumulation rates increases at all three sites between 17.5 Ma and 13.5 Ma paralleling the general trend of increasing foraminiferal δ13C records. We find highest export productivity (2-3 times modern values) during δ13C maxima. After the δ13C maximum at 14 Ma and the major step in Antarctic ice sheet growth, foraminiferal δ13C values decrease, but productivity continues to increase until 11 Ma the top of the investigated time interval. These observations suggest that different factors involving marine as well as terrestrial reservoirs of carbon must be considered when placing the results into the context of global carbon cycling and climate change.
Year of Publication: 2006
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Antarctic ice sheet; Antarctica; Atlantic Ocean; Biochemistry; Bioclastic sedimentation; C-13/C-12; Carbon; Carbon cycle; Cenozoic; Climate change; DSDP Site 608; Deep Sea Drilling Project; Foraminifera; Geochemical cycle; Geochemistry; Glacial environment; Glaciomarine environment; IPOD; Invertebrata; Isotope ratios; Isotopes; Leg 154; Leg 208; Leg 94; Marine environment; Microfossils; Middle Miocene; Miocene; Neogene; ODP Site 1265; ODP Site 925; Ocean Drilling Program; Paleo-oceanography; Paleoclimatology; Paleoecology; Productivity; Protista; Sedimentation; Sedimentation rates; Stable isotopes; Tertiary
Coordinates: N425012 N425013 W0230515 W0230515
N041215 N041216 W0432920 W0432922
S285000 S285000 E0023800 E0023800
Record ID: 2007079952
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