Collaborative Research: High-Resolution Deformation Rates, Spain

合作研究：高分辨率变形率，西班牙

• 批准号: 0409049
• 负责人: Josep Pares
• 金额: --
• 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: 2004
• 资助国家: 美国
• 起止时间: 2004-07-15 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409049&HistoricalAwards=false
• 关键词: Collaborative; Research; Resolution; Deformation; Rates

In order to understand the tectonic processes, which deform the Earth, it is important to know what long-term deformation rates are and how they vary through time. Typically, long chronologies of deformation have only coarse time resolution and evidence from many mountain belts suggests that deformation is discontinuous both spatially and temporally. In this study, climate signals driven by long-term variation in the Earth's orbit (Milankovitch cycles, Precession cyclicity every ~20,000 years, Obliquity cyclicity every ~40,000 years), are being used to provide high-resolution dating of sedimentary layers deposited atop a large, growing anticline, which developed in northern Spain (Jaca Basin) 42-36 million years ago. Growth strata, layers of rock deposited during deformation, provide a unique opportunity to unravel deformational and depositional processes of deforming landscapes and can provide exceptional time markers of deformation. This will be accomplished using structural, stratigraphic, and magnetic data from growth strata associated with the Pico del Aguila anticline, Spanish Pyrenees. Prolonged fold growth occurred in varying water depths and environments of deposition and was recorded by changes in growth strata thickness and orientation. As part of this study, the mesurement of stratigraphic sections and sampling of rocks for magnetic susceptibility, anisotropy of magnetic susceptibility, (rock magnetic proxies for orbitally driven climate variability) and remanent magnetization are being conducted. The climate signal is being analyzed by collaborative laboratory work and time series analysis. The characteristic remanent magnetization is being used to correlate the growth strata to the global magnetic polarity time scale, which provides an absolute date at eight specific horizons and the Milankovitch rhythms time other horizons every ~20,000 years. High-resolution Global Positioning System data, supported by UNAVCO, Inc., is being used to map individual beds in order to generate an equally high-resolution geometric reconstruction of the fold. Collectively, these measurements are permitting detailed reconstructions of deformation and providing novel insights into long-term deformation rates.

为了了解使地球变形的构造过程，重要的是要知道长期变形率是多少，以及它们如何随时间变化。通常，长时间的变形年表只有粗糙的时间分辨率，许多山带的证据表明，变形在空间和时间上都是不连续的。在这项研究中，由地球轨道长期变化驱动的气候信号（米兰科维奇旋回、每~2万年岁差旋回、每~4万年岁差旋回）被用于提供沉积层的高分辨率年代测定，这些沉积层沉积在一个巨大的、不断增长的背斜上，该背斜在42-36万年前发展于西班牙北部（Jaca盆地）。生长地层，在变形过程中沉积的岩层，提供了一个独特的机会来揭示变形景观的变形和沉积过程，并可以提供特殊的变形时间标志。这将利用与西班牙比利牛斯山脉Pico del Aguila背斜相关的生长地层的结构、地层和磁性数据来完成。在不同的水深和沉积环境下，褶皱生长时间延长，并通过生长层厚度和方向的变化来记录。作为这项研究的一部分，正在进行地层剖面测量和岩石磁化率采样，磁化率的各向异性，（轨道驱动气候变率的岩石磁性代用物）和剩余磁化。气候信号正在通过合作实验室工作和时间序列分析进行分析。利用特征剩余磁化强度将生长层与全球磁极时间尺度联系起来，这提供了8个特定层位的绝对日期，而其他层位的米兰科维奇节奏时间每~ 20000年。目前正在利用联安援助团支助的高分辨率全球定位系统数据绘制各个床的地图，以便对褶皱进行同样高分辨率的几何重建。总的来说，这些测量允许详细的变形重建，并提供长期变形率的新见解。