SGER: A New Method for Determining the Paleoelevation of Orogens

SGER：确定造山带古海拔的新方法

• 批准号: 0412509
• 负责人: Christian Teyssier
• 金额: $ 5.04万
• 依托单位: University of Minnesota-Twin Cities
• 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: 2004-03-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0412509&HistoricalAwards=false
• 关键词: SGER; New; Method; Determining; Paleoelevation

This small grant for exploratory research is investigating a new approach to determining paleoelevation of collapsed or eroded orogens using the stable isotope composition of mylonitic quartzite that interacted and equilibrated with meteoric water during deformation. During extensional collapse of the orogen, mateoric water penetrates the upper crust and interacts thoroughly with recrystallizing white mica in detachment mylonites. The isotopic composition of the meteoric water can be retrieved from the isotopic ratios measured in white micas, permitting a direct link to be made between the chemical and structural evolution of rocks at depth and the evolution of landscape and climate. Syn-kinematic white mica in the quartzite is dated using 40Ar/39Ar methods to determine the timing of deformation and interaction with fluids. Deuterium-hydrogen ratios measured in mica provide the link to elevation using existing climate models. Preliminary Results from the Shuswap core complex (British Columbia) indicate that the region was at an elevation of at least 4000 meters about 49 million years ago. The new method is being applied to mylonitic quartzite exposed in other core complexes in the Cordillera (Okanogan-Kettle Complex, Albion-Raft River-Grouse Creek Complex ) as a test of the reproducabilty of the method. The age of mylonitization varies from 50 to 15 million years old. Therefore, the method is being used to interpret the tectonics and paleoelevation of the Cordillera from Eocene to Miocene time. This technique is portable to other orogens and enhances understanding of the interaction among crustal dynamics, landscape evolution, and climate during orogeny.

这项用于探索性研究的小赠款正在研究一种新的方法，该方法是使用肌lon裂石英岩的稳定同位素组成来确定折叠或侵蚀的牛根的古征，该方法在变形过程中与气象相互作用和平衡。在造山带的延伸塌陷期间，配合水穿透了上皮，并与脱离肌lone的白色云母重结晶完全相互作用。可以从白色云母中测得的同位素比中检索流星水的同位素组成，从而允许在深度的岩石的化学和结构演化与景观和气候的演化之间建立直接联系。使用40AR/39AR方法确定石英岩中的合成白云母的日期，以确定变形和与流体相互作用的时机。在云母中测得的氘氢比提供了使用现有气候模型与海拔的联系。 Shuswap Core Complex（不列颠哥伦比亚省）的初步结果表明，该地区大约在4,900万年前的海拔至少4000米。新方法正在应用于在山脉（Okanogan-kettle Complex，Albion-Raft River-Grouse Creek Crops）中暴露于其他核心复合物中的mylonitic Quartzite，以测试该方法的繁殖体。甲误杆的年龄从50到1500万年不等。因此，该方法被用来解释从始新世到中新世的山脉的构造和古征。该技术可移植到其他牛根蛋白，并增强对地壳动力学，景观演化和造山机气候之间相互作用的理解。