Tectonic history of the northern Appalachian orogen

北阿巴拉契亚造山带的构造历史

• 批准号: 4230-2011
• 负责人: Barr, Sandra
• 金额: $ 1.6万
• 依托单位: Acadia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=473808
• 关键词: Tectonic; history; northern; Appalachian; orogen

Remnants of ancient mountain belts of various ages form most of the Earth's continents, including Canada. These remnants provide an opportunity to investigate mountain-building processes by exposing the internal architecture of the former mountains. My research proposal focuses on understanding the originally separate components (or "terranes") that came together between about 650 and 320 million years ago to form the Appalachian mountain belt. I hope to figure out more accurately when the pieces came together within that time span, whether they came as numerous separate blocks or as a single large composite block, and from where they came - possible source areas are now located in other continents, such as South America, Africa, and Europe, or they could have been pieces of ancestral North America that broke away and then came back again. My students and I will examine rocks in the field and map their distribution. We will collect representative samples and then in collaboration with colleagues who have the necessary equipment and expertise, we will find out the precise ages of the rocks and determine their mineral and chemical (including isotopic) compositions. We are planning to measure their ancient magnetic field directions, which can help us to estimate where they were located relative to the Earth's poles when they formed. Fossils present in the rocks will help us to know their ages relative to one another. All of these different types of information will be utilized to make interpretations about what was happening (and where) at the various times when each kind of rock was forming. Some features of the rocks, such as their isotopic compositions, may help us to know what kinds of rocks underlie those that we see at the surface, information that will help us to interpret from where the various terranes were derived. It is important to understand events and processes that happened even so long ago because they shaped the environment in which we now live, and provided the natural resources that enable us to not only survive but thrive on the Earth.

地球上的大部分大陆都是由不同年代的古代山带的残余物构成的，包括加拿大。这些遗迹通过暴露前山脉的内部建筑，为研究造山过程提供了机会。我的研究计划侧重于了解在大约6.5亿到3.2亿年前形成阿巴拉契亚山脉带的最初独立的组成部分（或“地体”）。我希望能更准确地弄清楚，在这段时间内，这些碎片是什么时候聚集在一起的，它们是作为多个独立的块体出现的，还是作为一个大的复合块体出现的，以及它们来自哪里——现在可能的来源区域位于其他大陆，比如南美、非洲和欧洲，或者它们可能是祖先北美的碎片，后来分离出来，然后又回来了。我和我的学生将在野外考察岩石并绘制它们的分布图。我们将收集有代表性的样品，然后与拥有必要设备和专业知识的同事合作，我们将找出岩石的精确年龄，并确定它们的矿物和化学成分（包括同位素）。我们正计划测量它们的古代磁场方向，这可以帮助我们估计它们形成时相对于地球两极的位置。岩石中的化石将帮助我们了解它们彼此之间的相对年龄。所有这些不同类型的信息将被用来解释每种岩石形成的不同时间发生了什么（以及在哪里）。岩石的一些特征，比如它们的同位素组成，可能会帮助我们了解我们在地表看到的岩石下面是什么样的岩石，这些信息将帮助我们解释各种地体的来源。了解很久以前发生的事件和过程是很重要的，因为它们塑造了我们现在生活的环境，并提供了自然资源，使我们不仅能够生存，而且能够在地球上茁壮成长。