Full Vector Studies of the Pringle Falls Excursion Recorded at Pringle Falls, Oregon

俄勒冈州普林格尔瀑布记录的普林格尔瀑布游览的完整矢量研究

• 批准号: 1215070
• 负责人: Emilio Herrero-Bervera
• 金额: $ 10.82万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1215070&HistoricalAwards=false
• 关键词: Full; Vector; Studies; Pringle; Falls

The main objective of this proposal is to investigate the relative paleointensity of the lake sediments that recorded the Pringle Falls excursion (ca. 218+/-1o ka) at the original site of Pringle Falls along the Deschutes River in Oregon. Paleomagnetic directions (i.e. Declination and Inclination) as well as the relative paleointensity (i.e. Full Vector) from the Pringle Falls sediments will provide information on the spatial and temporal variability of the Earth's geomagnetic field for the well documented aborted reversal at Pringle Falls which duration is of few hundred years. Due to the fact that there is a real need to obtain detailed records from high-resolution sediments (i.e. high sedimentation rates, at least 10cm/year) in order to have a better understanding of the generation of the field, we propose to study in detail five sections sampled along the Deschutes River with the main objective of understanding the directional behavior as well as the geomagnetic field strength (i.e. relative paleointensity of the sections) recorded before during and after the Pringle Falls excursion in Oregon.The objectives of this proposed study are primarily related to the knowledge of the paleofield variations during periods like reversals and excursions, and the critical time intervals that precede and follow the high resolution (i.e. at least 10 cm/year of sedimentation rates) Pringle Falls excursion (recorded in Oregon) that so far have only been documented from a few sedimentary sequences particularly between 30 to 220 thousand years of the geomagnetic history. Reversal and excursion studies cannot be separated from the surrounding polarity intervals and most records published so far were not long enough to provide complete information. The lacustrine sediments along the Deschutes River sections offer the first exceptional opportunity to document field changes over a time period thatincludes a polarity episode that lasted a few hundred to, at most, several thousand years, and thus document the field behavior over various time constants. The results of the rock magnetic tests/experiments performed on pilot samples indicate that the sediments in question are suitable for the relative paleointensity studies proposed here. The magnetic results of this proposed research will contribute to the understanding of the structure in the core of the Earth, the core-mantle and the inner and outer core boundaries as well as the related causes of the generation of the Earth's magnetic field.

本研究的主要目的是研究在俄勒冈州德舒特河沿岸的普林格尔瀑布原址记录的普林格尔瀑布漂移（约218+/- 10 ka）湖泊沉积物的相对古强度。从普林格尔瀑布沉积物中获得的古地磁方向（即赤纬和倾角）以及相对古强度（即全矢量）将为有文献记载的历时数百年的普林格尔瀑布倒转失败提供地球磁场时空变化的信息。由于确实需要从高分辨率沉积物（即高沉积速率，至少10cm/年）中获得详细记录，以便更好地了解该场的生成，我们建议详细研究沿德舒特河采样的五个剖面，主要目的是了解在俄勒冈普林格尔瀑布游览前后记录的方向行为以及地磁场强度（即剖面的相对古强度）。本研究的主要目的是了解古磁场在反转和偏移等时期的变化，以及在高分辨率（即至少10厘米/年的沉积速率）普林格尔瀑布偏移（记录在俄勒冈州）之前和之后的关键时间间隔，到目前为止，只有从少数沉积序列中记录，特别是在3万到22万年的地磁历史中。反转和偏移研究不能与周围的极性间隔分开，迄今为止发表的大多数记录不够长，无法提供完整的信息。德舒特河沿岸的湖泊沉积物提供了第一个特殊的机会来记录一段时间内的磁场变化，包括持续几百年到最多几千年的极性事件，从而记录了不同时间常数下的磁场行为。对试验样品进行的岩石磁性测试/实验结果表明，所讨论的沉积物适合本文提出的相对古强度研究。本研究的磁学结果将有助于了解地核结构、地核-地幔和内外核边界，以及地球磁场产生的相关原因。