Table 1. Radiocarbon dates from TPC522 and box core surface samples from BC521 and BC523

Recent intensification of wind-driven upwelling of warm upper circumpolar deep water (UCDW) has been linked to accelerated melting of West Antarctic ice shelves and glaciers. To better assess the long term relationship between UCDWupwelling and the stability of theWest Antarctic Ice Sheet, we present a multi-proxy reconstruction of surface and bottom water conditions in Marguerite Bay, West Antarctic Peninsula (WAP), through the Holocene. A combination of sedimentological, diatom and foraminiferal records are, for the first time, presented together to infer a decline in UCDW influence within Marguerite Bay through the early to mid Holocene and the dominance of cyclic forcing in the late Holocene. Extensive glacial melt, limited sea ice and enhanced primary productivity between 9.7 and 7.0 ka BP is considered to be most consistent with persistent incursions of UCDW through Marguerite Trough. From 7.0 ka BP sea ice seasons increased and productivity decreased, suggesting that UCDW influence within Marguerite Bay waned, coincident with the equatorward migration of the Southern Hemisphere Westerly Winds (SWW). UCDW influence continued through the mid Holocene, and by 4.2 ka BP lengthy sea ice seasons persisted within Marguerite Bay. Intermittent melting and reforming of this sea ice within the late Holocene may be indicative of episodic incursions of UCDW into Marguerite Bay during this period. The cyclical changes in the oceanography within Marguerite Bay during the late Holocene is consistent with enhanced sensitively to ENSO forcing as opposed to the SWW-forcing that appears to have dominated the early to mid Holocene. Current measurements of the oceanography of the WAP continental shelf suggest that the system has now returned to the early Holocene-like oceanographic configuration reported here, which in both cases has been associated with rapid deglaciation.近年来，暖性上层绕极深层水（upper circumpolar deep water, UCDW）的风力驱动上升流活动增强，这一现象已被证实与西南极冰架及冰川的加速消融存在关联。为更全面评估UCDW上升流与西南极冰盖稳定性之间的长期联系，我们针对南极半岛西部（West Antarctic Peninsula, WAP）玛格丽特湾的表层与底层海水环境，重建了全新世以来的多代用指标序列。本研究首次整合沉积学、硅藻及有孔虫三类记录，以此推断早全新世至中全新世期间玛格丽特湾内UCDW影响的逐步减弱，以及晚全新世时期周期性强迫作用占据主导的演化特征。距今9.7~7.0 ka BP时段内，大规模冰川融水、有限海冰覆盖与增强的初级生产力，与UCDW经玛格丽特海槽持续侵入湾内的情形高度一致。自7.0 ka BP起，海冰季时长增加且初级生产力下降，表明玛格丽特湾内UCDW的影响逐渐减弱，这一转变与南半球西风带（Southern Hemisphere Westerly Winds, SWW）向赤道迁移的事件同步发生。中全新世期间UCDW的影响仍持续存在，至4.2 ka BP时，玛格丽特湾内已出现长期稳定的海冰季。晚全新世时期海冰的间歇性消融与再形成，可能反映了此阶段UCDW间歇性侵入玛格丽特湾的过程。晚全新世时期玛格丽特湾内海洋学特征的周期性变化，与受ENSO（厄尔尼诺-南方涛动）强迫作用增强的敏感性特征相符，而非早全新世至中全新世时期占主导的南半球西风带强迫作用。当前对南极半岛西部大陆架海洋学特征的观测结果显示，该区域海洋系统现已回到本研究重建的早全新世型海洋状态，这两种情形均与快速冰消作用密切相关。