Glacial-interglacial sea surface temperature changes across the subtropical front east of New Zealand based on alkenone unsaturation ratios and foraminiferal assemblages

摘要: 0 are compared to those derived from foraminiferal assemblages (using the modern analog technique) in two of these cores. Reconstructions SST core tops and Holocene sediments agree well with average summer temperatures � 18� C subtropical waters 14� subpolar waters, a 4� -5� gradient across front. Down U37 K estimates indicate that regional was cooler during last glaciation an 10� waters. Temperature reconstructions alkenones for Holocene. In also glacial cooling C. contrast, subantarctic pre- 8� age warm season water 6� Thus suggest temperature front same or reduced slightly 3.5� -4� C, whereas it doubled Our results support previous work indicating STF remained fixed over Chatham Rise Last Glacial Maximum. However, differing techniques require additional explanation. A change euphotic zone profiles, seasonality growth, preferred growth depth must have affected recorded by biologically based proxies. Regardless specific reason, differential response environmental changes between climate regimes organisms on which suggests increased upwelling associated winds and/or shallowing thermocline stratification surface layer glaciation. INDEX TERMS: 4267 Oceanography: General: Paleoceanography; 4850 Biological Chemical: Organic marine chemistry; 1050 Geochemistry: Marine geochemistry (4835, 4850); 1055 geochemistry; KEYWORDS: paleoceanography, sea temperature, alkenones, Southern Ocean, Maximum