Deglacial to Holocene biomarker records of terrigenous input and sea surface temperature in the NW Pacific and the western Bering Sea

摘要: Polar regions are strongly affected by global climate change since warming is projected to be strongest in high latitudes. Understanding temperature changes crucial unravel the impact of there. Rising sea surface temperatures (SST) modify oceanographic conditions polar and subpolar seas. In northern hemisphere, increasing mean annual air (MAAT) lead thawing permafrost soils which may initiate release vast amounts fossil carbon environment. order study SST, MAAT intensity export from East Siberia adjacent NW Pacific Bering Sea over last deglaciation we analyzed terrigenous marine biomarkers (n-alkanes, branched GDGT & isoprenoid GDGTs) two sediment cores recovered at continental margin off Kamchatka peninsula (NW Pacific), western Sea. We test applicability TEX86 as a tool for SST-reconstructions thereby produce based SST-record The results compared Uk’37 Mg/Ca SST. record interpreted reflect summer subsurface temperatures. We further investigate CBT/MBT indices calculated GDGTs well δD n-alkanes tools reconstruction MAAT. on shows pattern similar Greenland ice core records with cooling events during Heinrich Event 1 (HE1) Younger Dryas (YD). late Holocene match modern peninsula. However, Last Glacial Maximum onset Bolling/Allerod interstadial (B/A) produces unrealistic that Holocene. Possibly LGM early reflects beginning B/A. When interpreting these findings one has keep mind concentrations very low (BIT lower than 0.1). Thus it questionable whether can used proxy signal in-situ production. In contrast our have hardly no similarity data. B/A does not differ but there slight decrease YD. While an abrupt increase 40 ‰ NW-Pacific gradual same magnitude whole period. During HE1 both show sharp reaching level. This indicates interglacial-like stadial conditions. Coeval CPI n-C23/n-C27 indicate overprinted source. Potential explanations include redeposition material mobilized deglacial sea-level rise, or permafrost. Terrigenous were quantified history export. Accumulation rates YD strikingly Preboreal indicating enhanced mobilization. Decomposing likely