SGER: Platinum Group Element Anomalies at Cryogenian Glacial Terminations

SGER：低温期冰川终止处的铂族元素异常

基本信息

批准号：
0821878
负责人：
Bernhard Peucker-Ehrenbrink
金额：
$ 1.5万
依托单位：
Woods Hole Oceanographic Institution
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2008
资助国家：
美国
起止时间：
2008-08-01 至 2009-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0821878&HistoricalAwards=false
关键词：
SGER Platinum Group Element Anomalies

项目摘要

SGER: Platinum Group element Anomalies at Cryogenian Glacial TerminationsBernhard Peucker-EhrenbrinkWoods Hole Oceanographic InstituteEAR-0821878AbstractThis project aims at determining whether Neoproterozoic glacial terminations are characterized by extraterrestrial platinum group element (PGE) anomalies. The original data (Bodiselitsch et al., Science, 2005) are consistent with extraterrestrial iridium enrichments in terminal Sturtian and Marinoan sediments. In contrast, unpublished data for the terminal Marinoan sediments in the Mackenzie Mountains, NW Canada, show PGE anomalies that are of terrestrial pedigree. These terrestrial anomalies reflect significant changes in sedimentation rates from glacial diamictites into the overlying postglacial cap carbonates.Based on the existing data from both locations it is unclear whether extraterrestrial anomalies are common features at Neoproterozoic glacial terminations. This project is designed to test the pedigree of PGE in continuous, well-characterized sections across sections of Marinoan glacial terminations that represent a transect from shallow shelf to deep slope depositional settings in NW Namibia. The gradient in depositional environments makes it more likely that in at least one location the full glacial-postglacial transition ? and thus the hypothesized extraterrestrial iridium anomaly ? is preserved.If extraterrestrial enrichments of PGE are confirmed, follow-up studies are needed to better constrain the globally integrated magnitude of the anomaly. The spatial heterogeneity of these anomalies may also help to improve ice-sheet models for Cryogenian glaciations.

SGER：低温冰川终端的铂族元素异常Bernhard Peucker-EhrenbrinkWoods Hole 海洋研究所EAR-0821878摘要该项目旨在确定新元古代冰川终端是否具有地外铂族元素 (PGE) 异常的特征。原始数据（Bodiselitsch 等人，Science，2005）与末期 Sturtian 和 Marinoan 沉积物中的外星铱富集一致。相比之下，加拿大西北部麦肯齐山脉马里诺末期沉积物的未发表数据显示，PGE 异常具有陆地谱系。这些陆地异常反映了从冰川混积岩到上覆的冰后盖碳酸盐沉积速率的显着变化。根据这两个地点的现有数据，尚不清楚地外异常是否是新元古代冰川终端的常见特征。该项目旨在测试马里诺冰川终止部分连续、特征良好的部分中的 PGE 谱系，这些部分代表了纳米比亚西北部从浅陆架到深坡沉积环境的横断面。沉积环境中的梯度使得至少在一个位置更有可能发生完整的冰期-后冰期转变？因此假设存在外星铱异常？如果证实地外存在 PGE 富集，则需要进行后续研究，以更好地限制该异常的全球综合规模。这些异常的空间异质性也可能有助于改进低温期冰川作用的冰盖模型。