Paleomagnetic Constraints Upon the Displacement History of the Alexander Terrane, Alaska

阿拉斯加亚历山大地体位移历史的古地磁约束

• 批准号: 8903898
• 负责人: Robert Coe
• 金额: $ 5.74万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-05-15 至 1991-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8903898&HistoricalAwards=false
• 关键词: Paleomagnetic; Constraints; Upon; Displacement; History

The collision and accretion of allochthonous terranes dominates the Mesozoic and Cenozoic history of the Pacific Northwest and Alaska. The largest terrane to dock was the amalgamated terrane sometimes referred to as "Baja British Columbia", so-called because included terranes such as Wrangellia have apparent primary Paleomagnetic vectors indicating low latitudes. However, available data from another included terrane (Alexander terrane) indicates no latitudinal movement since the late Triassic. As Alexander terrane lies to the south of Wrangellia, a severe spatial and timing problem exists. This project will attempt to resolve the paradox by extensive paleomagnetic analysis of sample collections from these terranes, including removal of overprints and determination of ages by 40Ar/39Ar techniques. Results offer the potential to resolve the tectonic sequence of assembly of the Pacific north- west terranes.

在太平洋西北地区和阿拉斯加的中、新生代历史中，主要是由异域地体的碰撞和增生所主导的。最大的陆地是合并的陆地，有时被称为“下不列颠哥伦比亚省”，之所以这么说，是因为包括的陆地，如弗兰格利亚，有明显的原始古地磁矢量，表明低纬度。然而，另一个包含的地体（亚历山大地体）的现有资料表明，自晚三叠世以来没有纬度运动。由于Alexander terrane位于Wrangellia的南部，因此存在严重的空间和时间问题。该项目将尝试通过对这些地块收集的样本进行广泛的古地磁分析来解决这个悖论，包括去除套印和用40Ar/39Ar技术确定年龄。研究结果为解决太平洋西北陆块组合的构造序列提供了可能。