Collaborative Research: High-Resolution Deformation Rates, Spain

合作研究：高分辨率变形率，西班牙

• 批准号: 0409077
• 负责人: David Anastasio
• 金额: --
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-15 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409077&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什么以及它们如何随时间变化。通常，长时间的变形年表只有粗略的时间分辨率，许多山区的证据表明，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（米兰科维奇周期，每20，000年一次的岁差周期，每40，000年一次的倾斜周期）被用来提供沉积在一个巨大的，不断增长的背斜上的沉积层的高分辨率测年，该背斜在西班牙北方（雅卡盆地）发展了4200万至3600万年。生长层，在变形过程中沉积的岩石层，提供了一个独特的机会，解开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记。 这将使用来自与西班牙比利牛斯山脉皮科德尔阿吉拉背斜相关的生长地层的构造、地层和磁性数据来完成。延长的褶皱生长发生在不同的水深和沉积环境中，并通过生长地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取样、磁化率各向异性（轨道驱动气候变化的岩石磁性指标）和反射磁化。目前正在通过合作实验室工作和时间序列分析对气候信号进行分析。 特征反射磁化被用于将生长地层与全球磁极性时间尺度相关联，该时间尺度提供了八个特定层位的绝对日期，而米兰科维奇节律则每20，000年对其他层位进行一次计时。高分辨率全球定位系统数据，由联合国志愿人员组织提供支助，正在被用来映射个别床，以产生一个同样高分辨率的几何重建的褶皱。总的来说，这些测量允许详细的变形重建，并提供新的见解长期变形率。