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Multiproxy record of suborbital-scale climate changes in the Algero-Balearic Basin during late MIS 20 - Termination IX
Quaternary Science Reviews ( IF 3.2 ) Pub Date : 2021-04-12 , DOI: 10.1016/j.quascirev.2021.106916
Ornella Quivelli , Maria Marino , Teresa Rodrigues , Angela Girone , Patrizia Maiorano , Adele Bertini , Gabriele Niccolini , Samanta Trotta , Franck Bassinot

High-resolution quantitative analyses have been carried out in samples from the Ocean Drilling Program (ODP) Site 975 in the Algero-Balearic basin through late Marine Isotope Stage (MIS 20)-Termination IX (800–784 ka). The multi-proxy study combines data of planktonic δ18O, δ13C, calcareous plankton (coccolithophores, foraminifera), palynomorphs, alkenone-based sea surface temperature (SST), % alkenone tetraunsatured (% C37:4), and terrigenous biomarkers (C23–C31 n-alkanes, C22–C30 n-alkanols) with the aim to reconstruct climate-induced paleoenvironmental changes at orbital-submillennial scale, in a crucial time interval of the Early-Midde Pleistocene transition. The surface water δ18Osw has been reconstructed from δ18OG.bulloides and alkenone-based SST as a proxy for salinity changes. The late MIS 20 has been subdivided in several phases based on evidence of (i) meltwater events of polar origin or from surrounding mountain glaciers, (ii) changes in the production rate of Western Mediterranean Deep Water (WMDW) and in deep water ventilation, (iii) variation in terrestrial input and river discharge, and iv) variations in the strength of the north westerlies, and polar front shift. Following a glacial stadial (lasting ca 3 kyr) marked by the strongest WMDW production, coeval with a boreal summer insolation minimum and a marked low sea level, the latest MIS 20 is characterized by a terminal stadial event (lasting ca 3.5 kyr), which is traced by the occurrence of cold-low salinity water, pointing to meltwater advection at the site location. Short-term warm and cool events occurred through Termination IX during sea level rise and insolation increase, preceding the onset of full MIS 19c, characterized by an organic rich layer (ORL) associated with insolation cycle 74. The succession of these climate and oceanographic events has been compared to evidences from other Mediterranean sites, highlighting similar basin-wide patterns, which recall the climate evolution of Termination I. The comparison of our results with the climate proxies from the Integrated Ocean Drilling Program (IODP) Site U1385 located west of Iberian margin made it possible to point at the connection between Mediterranean oceanographic and atmospheric dynamics and the northern hemisphere ice-sheet instability, providing insight on the relationship with the Atlantic meridional overturning circulation and thermal front migration.



中文翻译:

MIS 20后期-IX终止期阿尔及利亚-巴利阿里盆地亚轨道尺度气候变化的多代理记录

在阿尔及利亚-巴利阿里盆地的海洋钻探计划(ODP)站点975中,通过后期海洋同位素阶段(MIS 20)-IX终端(800-784 ka)对样品进行了高分辨率的定量分析。浮游δ所述的多代理研究联合数据18 O,δ 13 C,钙质浮游生物(颗石藻,有孔虫),孢粉,基于烯酮海表面温度(SST),%烯酮tetraunsatured(%C 37:4),和陆源生物标志物(C 23 -C 31 链烷烃,C 22 -C 30 ñ(链烷醇),目的是在早中更新世过渡的关键时间间隔内,重建气候引起的古环境变化,并在轨道下的亚千年尺度上进行。表面水δ 18 ö SW已从δ重建18个ö G.bulloides以及基于烯酮的SST作为盐度变化的代理。根据(i)极性起源的融水事件或来自周围山地冰川的证据,(ii)西地中海深水(WMDW)生产率的变化和深水通风的证据,MIS 20后期被细分为多个阶段, (iii)地面输入和河流流量的变化,以及iv)北西风强度和极地前移的变化。继以最大的WMDW产量为特征的冰期恒星(持续约3年)之后,伴随着夏季的日照量最少和海平面显着下降,最新的MIS 20的特征是末期恒星事件(持续了约3.5年)。由低盐度的冷水追踪到,表明该地点的融水平流。

更新日期:2021-04-13
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