Collaborative Research: RUI: Testing Models of Passive Margin Rejuvenation in the Eastern U.S.

合作研究：RUI：测试美国东部被动利润回春的模型

• 批准号: 1624168
• 负责人: Michael Simpson
• 金额: $ 5.59万
• 依托单位: SUNY College at Plattsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1624168&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Testing; Models

The eastern North American continental margin was established during the Jurassic Period (about 145 to 200 million years ago) during the opening of the Atlantic Ocean and is thought to have remained tectonically stable since that time. However, recent evidence suggests tectonically driven uplift and erosion events occurred between 100 and 130 and between 15 and 2 million years ago, long after the rift episode. Similar events have been recognized on the margins of other continents bordering the Atlantic. The objective of this project is to determine the timing and spatial distribution of these events in eastern North America with the goal of establishing the relationship with events on other continents and, ultimately, provide constraints on possible tectonic mechanisms to explain synchronous events. The project will advance desired societal outcomes by the development of a grade 9-12 earth science module in collaboration with local schools with class visits and visits to Middlebury and intensive involvement of undergraduate students in research.This project aims to understand rejuvenation of the Eastern North American margin, which remains virtually unknown compared to relatively well-documented rejuvenation events on the coasts of Africa, South America, Europe, and the north Atlantic. Preliminary data (increased sediment flux to the Baltimore Canyon Trough; thermochronology in the White Mountains, New Hampshire) suggest that at least three rejuvenation events occurred along the Eastern North American margin: Early Cretaceous (130-110 Ma), Late Cretaceous (85-65 Ma), and the Mio-Pliocene (15-0 Ma). Results from other Atlantic margins highlight two periods, the Late Cretaceous and Mio-Pliocene, in which rejuvenation may have occurred synchronously across multiple circum-Atlantic margins. This coincident timing raises the question of whether a common forcing mechanism can rejuvenate multiple passive margins at the same time? Two end-member hypotheses include: (1) lateral stresses transmitted long distances through the lithosphere, or (2) dynamic mantle stresses beneath passive margins (e.g. dynamic topography). On the large scale, a complete picture of which margins were synchronously rejuvenated and how they are geometrically related may be used to infer Atlantic-scale forcing mechanisms. On the local scale, delineating the spatiotemporal pattern of rejuvenation of the Eastern North American margin may reveal stress orientations or local fault mechanics, thus constraining the underlying forcing mechanism. This project uses both of these approaches to clarify the pattern of post-rift exhumation in the central Eastern North American margin (New England, New York, and New Jersey). The research team will determine time-resolved exhumation histories by using apatite and zircon U-Th/He and apatite fission track thermochronology in bedrock drill cores and sediment provenance using trace element composition of heavy minerals and U-Pb dating of zircon and rutile and provenance of sediments in offshore drill cores from the Baltimore Canyon Trough. These two approaches are complementary; thermochronology provides the timing and magnitude of exhumation at a point, whereas detrital provenance integrates a broad range of possible source regions and can detect exhumation events too small to reset thermochronometers.

在侏罗纪时期（大约145至2亿年前）在大西洋开放期间建立了东部北美大陆的边缘，自那时以来，人们认为这在构造方面一直保持稳定。然而，最近的证据表明，构造驱动的隆起和侵蚀事件发生在100至130至15到200万年前的15到200万年前。在与大西洋接壤的其他大洲的边缘上也认识到类似的事件。该项目的目的是确定北美东部这些事件的时间和空间分布，目的是建立与其他大陆上事件的关系，并最终对可能的构造机制提供限制，以解释同步事件。该项目将通过与当地学校合作开发9-12年级的地球科学模块来提高期望的社会成果大西洋。 Preliminary data (increased sediment flux to the Baltimore Canyon Trough; thermochronology in the White Mountains, New Hampshire) suggest that at least three rejuvenation events occurred along the Eastern North American margin: Early Cretaceous (130-110 Ma), Late Cretaceous (85-65 Ma), and the Mio-Pliocene (15-0 Ma).其他大西洋边缘的结果突出了两个时期，即晚白垩纪和米尔二世，其中可能已经在多个环境边缘同步发生了复兴。这个偶然的时机提出了一个问题，即是否可以同时恢复多个被动边缘？两个末端成员的假设包括：（1）横向应力通过岩石圈传播长距离，或（2）被动边缘下方的动态地幔应力（例如，动态地形）。在大规模上，将边缘同步复兴的完整图片以及它们与几何相关的方式可用于推断大西洋规模的强迫机制。在地方规模上，描绘了东北美边缘的复兴时空模式可能会揭示压力取向或局部断层力学，从而限制了基本强迫机制。该项目使用这两种方法来阐明北美东部中部（新英格兰，纽约和新泽西州）的裂谷后挖掘模式。研究团队将使用apatite和锆石U-th/and apatite裂变轨道轨道热量学在基岩钻芯和沉积物中使用重型矿物质的痕量元素组成，以及锆石和锆石的U-pb定位的痕量元素组成，并在Offshore Drill drill off Baltimore Can yyyon frough来确定apatite u-th/and a apatite裂变轨道热量的浮游生物组成和沉积物的痕量元素组成。这两种方法是互补的。热量学提供了一个点的时机和幅度，而碎屑出处则整合了广泛的可能的源区域，并且可以检测到太小而无法重置热力学计的挖掘事件。