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: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=507586
• 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.

不同时代的古代山脉的遗迹形成了地球上的大部分大陆，包括加拿大。这些遗迹提供了一个机会，通过暴露以前山脉的内部建筑来调查造山过程。我的研究计划侧重于了解最初独立的组成部分(或称“地体”)，它们在大约6.5亿到3.2亿年前聚集在一起，形成了阿巴拉契亚山脉带。我希望更准确地找出这些碎片在那段时间内聚集在一起的时间，它们是作为多个独立的地块出现的，还是作为一个单一的大型复合地块出现的，以及它们来自哪里--可能的物源区现在位于其他大陆，如南美、非洲和欧洲，或者它们可能是北美祖先的碎片，它们脱离了，然后又回来了。我和我的学生将检查野外的岩石，并绘制它们的分布图。我们将收集具有代表性的样本，然后与拥有必要设备和专业知识的同事合作，查明岩石的准确年龄，并确定其矿物和化学(包括同位素)组成。我们正计划测量它们古老的磁场方向，这可以帮助我们估计它们形成时相对于地球两极的位置。岩石中存在的化石将帮助我们了解它们彼此之间的年龄。所有这些不同类型的信息都将被用来解释在每种岩石形成的不同时间发生了什么(以及在哪里发生)。岩石的某些特征，如它们的同位素组成，可能有助于我们知道我们在地表看到的那些岩石下面是什么类型的岩石，这些信息将有助于我们解释各种地体的来源。了解很久以前发生的事件和进程很重要，因为它们塑造了我们现在生活的环境，并提供了使我们不仅能够在地球上生存而且能够在地球上茁壮成长的自然资源。