A Possible Lacustrian Record of the Blake Episode from La Pine Oregon

从俄勒冈州拉派恩附近一段20米长的硅藻质湖泊沉积物中恢复了一段高分辨率的地磁极性事件记录。这一记录的年代被限制在18,000年到0.6英里之间。根据来自湖床序列较老部分的花粉日期和覆盖在湖床上的年轻冰川沉积的年龄。该记录提供了VGP路径，该路径标识了半径为60o的明确的顺时针NE到SW环路，紧随其后的是第二个特征(较年轻的)，该特征描绘出位于NE象限的直径为30度且以浅倾斜为特征的逆时针方向。这两个特征与布莱克事件中的两个特征相似(距今10.5万年和11.4万年)。PI将通过对20米剖面附近的平行剖面进行抽样来研究这一现象。此外，他还将进行实地工作，以识别和关联该部分中存在的标记层位，以便更准确地确定野外可能出现的漂移的日期。计划进行热释光实验，以验证计时学工作。

A high-resolution record of a geomagnetic polarity episode has been recovered from a 20-meter section of diatomaceous lacustrine sediments from near La Pine, Oregon. The age of this record is constrained between 18,000 years and 0.6 m.y. based upon a pollen date from the older part of the lakebed sequence and the age of the younger glacial deposits that overlie the lakebeds. The record provides a VGP path that identifies a well- defined clockwise NE to SW loop with a radius of 60o, followed a second feature (younger) that traces out a counterclockwise which is 30 degrees in diameter residing in the NE quadrant and characterized by shallow inclinations. These two characteristic features are similar to the two features present in the Blake event (105,000 years and 114,000 years B.P.). The PI will study this phenomenon by sampling nearby parallel sections to the 20- meter profile. In addition, he will do field work to identify and correlate the marker horizons present in the section to date more accurately the possible excursion in the field. Thermoluminescence experiments are planned to verify the tephrachronology work.