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Rommerskirchen, Florian; Condon, Tegan; Mollenhauer, Gesine; Dupont, Lydie M; Schefuß, Enno (2011): (Table 1) TOC content, BIT, TEX86 and UK'37 indices, and sea surface temperature reconstruction for the middle Miocene to Pliocene of ODP Hole 175-1085A. doi:10.1594/PANGAEA.770426,
Supplement to: Rommerskirchen, F et al. (2011): Miocene to Pliocene development of surface and subsurface temperatures in the Benguela Current system. Paleoceanography, 26, PA3216, doi:10.1029/2010PA002074

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Abstract:
The initiation of the Benguela upwelling has been dated to the late Miocene, but estimates of its sea surface temperature evolution are not available. This study presents data from Ocean Drilling Program (ODP) Site 1085 recovered from the southern Cape Basin. Samples of the middle Miocene to Pliocene were analyzed for alkenone-based (UK'37, SSTUK) and glycerol dialkyl glycerol tetraether (GDGT) based (TEX86, TempTEX) water temperature proxies. In concordance with global cooling during the Miocene, SSTUK and TempTEX exhibit a decline of about 8°C and 16°C, respectively. The temperature trends suggest an inflow of cold Antarctic waters triggered by Antarctic ice sheet expansion and intensification of Southern Hemisphere southeasterly winds. A temperature offset between both proxies developed with the onset of upwelling, which can be explained by differences in habitat: alkenone-producing phytoplankton live in the euphotic zone and record sea surface temperatures, while GDGT-producing Thaumarchaeota are displaced to colder subsurface waters in upwelling-influenced areas and record subsurface water temperatures. We suggest that variations in subsurface water temperatures were driven by advection of cold Antarctic waters and thermocline adjustments that were due to changes in North Atlantic deep water formation. A decline in surface temperatures, an increased offset between temperature proxies, and an increase in primary productivity suggest the establishment of the Benguela upwelling at 10 Ma. During the Messinian Salinity Crisis, between 7 and 5 Ma, surface and subsurface temperature estimates became similar, likely because of a strong reduction in Atlantic overturning circulation, while high total organic carbon contents suggest a "biogenic bloom." In the Pliocene the offset between the temperature estimates and the cooling trend was reestablished.
Project(s):
Coverage:
Latitude: -29.374410 * Longitude: 13.990110
Date/Time Start: 1997-09-26T00:15:00 * Date/Time End: 1997-09-29T18:15:00
Minimum DEPTH, sediment/rock: 0.51 m * Maximum DEPTH, sediment/rock: 603.79 m
Event(s):
175-1085A * Latitude: -29.374410 * Longitude: 13.990110 * Date/Time Start: 1997-09-26T00:15:00 * Date/Time End: 1997-09-29T18:15:00 * Elevation: -1713.2 m * Penetration: 604 m * Recovery: 594.39 m * Location: Benguela Current, South Atlantic Ocean * Campaign: Leg175 * Basis: Joides Resolution * Device: Drilling/drill rig (DRILL) * Comment: 64 cores; 604 m cored; 0 m drilled; 98.4 % recovery
Comment:
Sediment depth is given in mbsf. Age is after Berger et al. (2002, doi:10.2973/odp.proc.sr.175.235.2002), Vidal et al. (2002, doi:10.1016/S0025-3227(01)00206-7), and Westerhold et al. (2005, doi:10.1016/j.palaeo.2004.12.001).
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethodComment
1Sample code/labelLabelRommerskirchen, FlorianODP sample designation
2Sample thicknessSamp thickcmRommerskirchen, Florian
3DEPTH, sediment/rockDepthmGeocode
4Depth, compositeDepth compmcdRommerskirchen, FlorianIntercore correlationlog depth after Wefer et al. (1998, doi:10.2973/odp.proc.ir.175.1998)
5AGEAgeka BPGeocode
6Carbon, organic, totalTOC%Rommerskirchen, FlorianElement analyser CHN-O Rapid, Heraeus
7Alkenone, unsaturation index UK'37UK'37Rommerskirchen, FlorianHigh Performance Liquid Chromatography coupled mass spectrometer (HPLC-MS)
8Alkenone, unsaturation index UK37, standard deviationUK37 std dev±Rommerskirchen, FlorianHigh Performance Liquid Chromatography coupled mass spectrometer (HPLC-MS)
9Sea surface temperature, annual meanSST (1-12)°CRommerskirchen, FlorianCalculated from UK'37 (Müller et al, 1998)
10Sea surface temperature, annual mean, standard deviationSST (1-12) std dev±Rommerskirchen, FlorianCalculated from UK'37 (Müller et al, 1998)
11Branched and isoprenoid tetraether indexBITRommerskirchen, FlorianHigh Performance Liquid Chromatography coupled mass spectrometer (HPLC-MS)
12Branched and isoprenoid tetraether index, standard deviationBIT std dev±Rommerskirchen, FlorianHigh Performance Liquid Chromatography coupled mass spectrometer (HPLC-MS)
13Tetraether index of 86 carbon atomsTEX86Rommerskirchen, FlorianHigh Performance Liquid Chromatography coupled mass spectrometer (HPLC-MS)
14Tetraether index of 86 carbon atoms, standard deviationTEX86 std dev±Rommerskirchen, FlorianHigh Performance Liquid Chromatography coupled mass spectrometer (HPLC-MS)
15Sea surface temperature, annual meanSST (1-12)°CRommerskirchen, FlorianCalculated from TEX86 (Kim et al., 2010)
16Sea surface temperature, annual mean, standard deviationSST (1-12) std dev±Rommerskirchen, FlorianCalculated from TEX86 (Kim et al., 2010)
Size:
1483 data points

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