Terrestrial and marine floral response to latest Eocene and Oligocene events on the Antarctic Peninsula
Terrestrial and marine floral response to latest Eocene and Oligocene events on the Antarctic Peninsula
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陆地和海洋花卉对南极半岛最新始新世和渐新世事件的反应
DOI：
10.1080/01916122.2017.1418444
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发表时间：
2019
期刊：
影响因子：
1.5
通讯作者：
Tatur, Andrzej
中科院分区：
文献类型：
--
作者：
Warny, Sophie;Kymes, C. Madison;Askin, Rosemary;Krajewski, Krzysztof P.;Tatur, Andrzej
来自南极最北端半岛两侧的孢粉学结果提供了对始新世-渐新世过渡期（EOT）之前的陆地植被和海面状况的见解，通过早渐新世冰川条件和随后的晚渐新世间冰期。最新的始新世样品集从最高的拉梅塞塔组西摩岛，詹姆斯罗斯（弧后）盆地，记录了低多样性Nothofagus（南部山毛榉）为主的植被与一些podocarp针叶树类似瓦尔迪维亚型森林今天在智利和阿根廷发现。海洋有机壁浮游植物包括潜光层和始新世甲藻孢囊，如Vozzhennikovia rotunda、V. apertura、Senegalinium asymmetricum和Spinidinium macmurdoense。在EOT之前，在该部分的顶部附近的陆地palynomorphs减少，增加返工标本，消失的关键dinocysts，和大量的海冰指示leiosphere加上小的甲藻cystImpletosphaeridium信号的冰川条件下，在亚极地气候的开始。从南设得兰群岛国王乔治岛（岩浆弧）的波洛内兹湾和男孩角地层的早渐新世至晚渐新世样品中，发现了一种极度贫瘠的陆生植物群，这可能部分是由于波洛内兹冰川期植被覆盖不良，但也是由于持续的区域火山活动对植被的破坏。海冰指示leiospheres在海洋polynomorph组件的流行是一致的极地到亚极地条件下，在波罗奈兹冰川。
Palynological results from opposite sides of the northernmost Antarctic Peninsula provide insight on terrestrial vegetation and sea-surface conditions immediately before the Eocene–Oligocene transition (EOT), through Early Oligocene glacial conditions and the subsequent Late Oligocene interglacial interval. A latest Eocene sample set from the uppermost La Meseta Formation on Seymour Island, James Ross (back-arc) Basin, records a low-diversityNothofagus(southern beech)-dominated vegetation with some podocarp conifers similar to Valdivian-type forest found today in Chile and Argentina. Marine organic-walled phytoplankton include leiospheres and Eocene dinoflagellate cysts such asVozzhennikovia rotunda,V. apertura,Senegalinium asymmetricumandSpinidinium macmurdoense. Immediately before the EOT near the top of the section the decrease in terrestrial palynomorphs, increase in reworked specimens, disappearance of key dinocysts, and overwhelming numbers of sea-ice-indicative leiospheres plus the small dinoflagellate cystImpletosphaeridiumsignal the onset of glacial conditions in a subpolar climate. Early to Late Oligocene samples from the Polonez Cove and Boy Point formations on King George Island, South Shetland Islands (magmatic arc), yielded an extremely depauperate terrestrial flora, likely resulting in part from poor vegetation cover during the Polonez Glaciation but also because of destruction of vegetation due to continued regional volcanism. The prevalence of sea-ice-indicative leiospheres in the marine palynomorph component is consistent with polar to subpolar conditions during and following the Polonez Glaciation.