东海北部陆缘地区全新世孢粉组合及其古环境演变

对东海北部陆缘地区NH 0504孔和东海Dh1井全新世地层的孢粉进行了研究,划分出5个孢粉组合带和2个亚带,恢复了该地区植被演替、气候波动和古环境演变的5个阶段,为该区的地层年代划分和对比提供了科学的证据,为全新世古植被、古气候和古环境的重建提供了重要的孢粉学资料。划分的5个阶段为:第1阶段为针阔叶混交林-草地,反映出当时的气候以温凉略湿为特征(前北方期);第2阶段为含常绿阔叶树的针阔叶混交林,反映出当时的气候以温和略干为特征(北方期);第3阶段为以常绿栎类和栲属等为主的常绿阔叶林,反映出当时气候以热暖潮湿为特征(大西洋期);第4阶段是以栎、松和禾本科为主的针阔叶混交林,反映出当时的气候以温暖略干为特征(亚北方期);第5阶段是以落叶栎类、常绿栎类、松为主的落叶阔叶、常绿阔叶、针叶混交林-草地,反映出当时的气候以温暖湿润为特征(亚大西洋期)。     

Identification of Atlantic water inflow on the north Svalbard shelf during the Holocene

Nordaustlandet is located in the northeastern part of the Svalbard archipelago, within the northernmost reach of the West Spitsbergen Current. This current transports Atlantic water to the Arctic Ocean along the western and northern Svalbard margins. This region is well-suited for reconstructing the history of changing Atlantic water inflow to the Arctic Ocean. We studied the marine sediment core HH12-04-GC from Rijpfjorden. Benthic foraminiferal assemblages and sedimentological data are combined to reconstruct the palaeoenvironment of the fjord from the end of the last local deglaciation to the late Holocene. The local deglaciation, between 11.3 and 10.6 cal ka bp , was dominated by active glacier calving processes, associated with a strong inflow of Atlantic water. This led to the establishment of glaciomarine conditions. The Holocene was initially characterised by a relatively stable and warm environment associated with a strong contribution of Atlantic water. Glaciomarine influence progressively decreases after 9.7 cal ka bp and the Atlantic water contribution increases. The late Holocene displayed a similar environment to today, with the influence of glaciomarine conditions and limited Atlantic water inflow. These results confirm that Atlantic water inflows made a continuous contribution to northern Nordaustlandet throughout the postglacial period.     

Local and regional constraints on relative sea-level changes in southern Isle of Skye,Scotland, since the Last Glacial Maximum

New relative sea-level (RSL) data constrain the timing and magnitude of RSL changes in the southern Isle of Skye following the Last Glacial Maximum (LGM). We identify a marine limit at ~23 m OD, indicating RSL ~20 m above present c. 15.1 ka. Isolation basin data, supported by terrestrial and marine limiting dates, record an RSL fall to 11.59 m above present by c. 14.2 ka. This RSL fall occurs across the time of global Meltwater Pulse 1A, supporting recent research on the sources of ice melting. Our new data also help to resolve some of the chronological issues within the existing Isle of Skye RSL record and provide details of the sub-Arctic marine environment associated with the transition into Devensian Lateglacial climate at c. 14.5 k cal a bp , and the timing of changes in response to the Loch Lomond Stadial climate. Glacio-isostatic adjustment (GIA) model predictions of RSL deviate from the RSL constraints and reflect uncertainties in local and global ice models used within the GIA models. An empirical RSL curve provides a target for future research.