A Paleomagnetic Study of the Blake Event in Chinese Loess-Paleosol Sequences

中国黄土-古土壤层序布莱克事件的古地磁研究

• 批准号: 9903074
• 负责人: Rob Van der Voo
• 金额: $ 15万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9903074&HistoricalAwards=false
• 关键词: Paleomagnetic; Study; Blake; Event; Chinese

9903074 Van der VooThe Blake Event is a short-duration reversed interval in the Brunhes Chron. It is thought to have occurred about 125,000 years B.P, although its age is poorly constrained. It possibly included multiple reversals (up to three reversed intervals have been reported). The PI intends to obtain up to seven parallel records from Chinese loesses and paleosols near Lanzhou, where the Blake Event has previously been observed in a few places. The goals are (1) to constrain the beginning and end dates of the Event, (2) to verify whether the Event consists of multiple reversals or not, and (3) to determine whether some of the loess-paleosol sequences acquired their remanent magnetizations with a significant delay. This delay time, in turn, is critical to correct inferred ages for older reversal boundaries in the loess, such as the Matuyama-Brunhes boundary. A mismatch exists in the literature between the paleoclimatic stage in which this reversal is recorded in the Chinese loess (a cold interval) and that recorded in deep-marine sequences (a warm interval). Once delay times (if any) have been quantified, the PI will attempt to correlate these factors with environmental parameters, such as precipitation, sedimentation rates, or degree of pedogenesis, as revealed through rock magnetic studies of the magnetic minerals. This correlation is important to assess the use of magnetic parameters as paleoclimatic proxies, particularly for the evolution of Asian and Indian monsoonal patterns.

9903074货车德沃布莱克事件是布鲁赫年代的一个短持续时间的反转间隔。它被认为发生在B.P约125，000年，尽管它的年龄限制得很小。 可能包括多次逆转（报告了最多3次逆转间期）。 PI打算从兰州附近的中国黄土和古土壤中获得多达7个平行记录，此前在兰州的一些地方观察到了布莱克事件。 其目的是：（1）限制事件的开始和结束日期，（2）验证事件是否由多次反转组成，以及（3）确定某些黄土-古土壤序列是否具有明显的延迟获得其反射磁化。 这种延迟时间，反过来，是至关重要的，以纠正推断年龄的老反转边界在黄土中，如Matuyama-Brunhes边界。 在中国黄土中记录的这种反转的古气候阶段（冷间隔）和深海序列中记录的古气候阶段（暖间隔）之间存在着不匹配。 一旦延迟时间（如果有的话）被量化，PI将尝试将这些因素与环境参数相关联，如降水、沉积速率或成土作用的程度，如通过磁性矿物的岩石磁性研究所揭示的。 这种相关性是很重要的，以评估使用磁参数作为古气候代理，特别是亚洲和印度季风模式的演变。