Collaborative Research: Resolving Conflicting Models for the Laramide Orogeny and the Flat-Slab Paradigm in the Southern California Batholith

合作研究：解决拉拉米德造山运动模型与南加州基岩平板范式之间的冲突

• 批准号: 2138734
• 负责人: Keith Klepeis
• 金额: $ 28.89万
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2138734&HistoricalAwards=false
• 关键词: Collaborative; Research; Resolving; Conflicting; Models

Understanding how the Rocky Mountains developed in the western United States is a problem of vital importance because they host precious mineral resources such as gold, lead, copper, and silver, which are important for our national economy. Many of these economic resources were brought to the surface along large faults which formed in the Late Cretaceous during a mountain building event, termed the Laramide orogeny. A key problem is that the timing and origin of the driving force behind this event and the formation of the Rocky Mountains are highly controversial and there is no consensus on the tectonic setting in which these mountains formed. The investigators hypothesize that the answer to understanding the origin of the Rocky Mountains and the Laramide orogeny lies in the San Gabriel Mountains of southern California. This region contains two important features which make it the focus of this study: (1) they preserve a complete temporal history of the Laramide orogeny from the earliest phase until its termination, which is important in reconstructing the driving force behind the event, and (2) they contain a unique section of the deep crust including a major ductile fault system that was active during the beginning of the Laramide orogeny. Analysis of these features will offer critical insights on the beginning of the Laramide orogeny, which will be essential in resolving conflicting hypotheses. The research plan for this project will involve 3 seasons of field work and data collection in the San Gabriel and nearby mountains. Laboratory analyses of rocks collected from the San Gabriel Mountains will consist of geochronology, geochemistry and microstructural work at the California State University Northridge Laser Ablation and LatinXellence in STEM Laboratories. The project will advance societal outcomes through innovative summer workshops, and an academic-year mentoring program termed, LA-ROCS, both of which are aimed at providing research experiences to underrepresented students at minority-serving institutions in southern California. These mentorship and research opportunities for undergraduate students will expose them to cutting-edge analytical research facilities and will aid in developing a diverse, globally competitive STEM workforce. This proposal aims to resolve the controversial beginnings of the Laramide orogeny by testing conflicting hypotheses about the origin and tectonic effects of Laramide orogenesis on the evolution of the Southern California batholith at ca. 85-70 million years ago. This critical period in the development of the U.S. Cordillera is commonly associated with shallow-slab subduction beneath Southern California, which is thought to have driven the transition from thin-skin (Sevier-style) to thick-skin (Laramide-style) deformation. A key problem with the flat-slab model is that the team's preliminary geochronology data show that the initiation of the Laramide orogeny in Southern California is spatially and temporally linked to a magmatic flare-up event in the same region where flat-slab subduction is postulated to have occurred. This contradiction makes the Laramide orogeny distinct from other areas of flat-slab subduction, including the modern-day Sierras Pampeanas in Argentina, which is characterized by a magmatic gap. To resolve this problem, the investigators propose a multiscale approach that focuses on the roots of the Southern California batholith and combines field work with a variety of state-of-the art analytical techniques (Uranium-Lead geochronology, Hafnium- and Osmium-isotope geochemistry, electron backscatter diffraction (EBSD) and microstructural analysis, structural analyses along continuous transects). These data will allow the investigators to link magmatism in the Southern California batholith with deformation and plate-kinematic information at mid-lower crustal depths to resolve conflicting models associated with the flat-slab paradigm and the initiation of the Laramide orogeny.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

了解在美国西部发展的落基山是一个至关重要的问题，因为它们拥有对我们的国民经济很重要的黄金，铅，铜和白银等宝贵的矿产资源。这些经济资源中有许多被带到山区建筑事件中晚白垩统事件中形成的大断层中，称为laramide造口。一个关键的问题是，这一事件背后的动力和落基山的形成的时机和起源是高度争议的，在这些山脉形成的构造环境上没有共识。调查人员假设了解洛矶山脉的起源和拉拉米德的起源的答案在于南加州的圣加布里埃尔山脉。该区域包含两个重要特征，使其成为这项研究的重点：（1）它们从早期到终止终止，保留了Laramide造成的完整临时历史，这对于重建事件背后的驱动力很重要，（2）它们包含深层壳的独特部分，其中包括在Laramide erogeny the Laramide ecoregeny in n the Laramide the Intive the Laramide the Intive the Extive the活动。对这些特征的分析将提供有关Laramide造山基因开头的关键见解，这对于解决相互矛盾的假设至关重要。该项目的研究计划将涉及圣加布里埃尔和山区附近的3个季节的现场工作和数据收集。从圣加布里埃尔山（San Gabriel Mountains）收集的岩石的实验室分析将包括加利福尼亚州立大学诺斯里奇（Northridge）激光消融和STEM实验室的拉丁裔的地球化学，地球化学和微观结构工作。该项目将通过创新的夏季研讨会来提高社会成果，并被称为LA-ROCS的学年心理计划，旨在为南加州少数派服务机构的代表性不足的学生提供研究经验。这些本科生的心态和研究机会将使他们暴露于尖端的分析研究机构，并有助于发展多样性，具有全球竞争性的STEM劳动力。 该提案旨在通过测试有关拉胺造山学对ca南加州巴斯托里斯南加州巴斯托斯进化的起源和构造作用的相互矛盾的假设来解决Laramide造山运动的有争议的开始。 85-7亿年前。在美国山内利拉（Cordillera）开发的关键时期通常与南加州下方的浅斜线俯冲有关，这被认为是从薄皮（Sevier风格）到厚皮（Laramide）变形的过渡。平板模型的一个关键问题是，该团队的初步地球人工学数据表明，在南加州的Laramide的启动在空间上且暂时与同一地区的岩浆爆炸事件相关，该地区假定扁平板俯冲俯冲的假设是发生了发生的。这一矛盾使Laramide的造山基因与其他平板俯冲区域不同，包括阿根廷的现代Sierras Pampeanas，其特征是岩浆间隙。为了解决这个问题，研究人员提出了一种多尺度方法，该方法重点介绍了南加州浴位的根源，并将现场工作与各种最先进的艺术分析技术（铀领域学，hafnium and hafnium and osmium-isotope地球化学，电子后划分衍射（EBSD）和Microstructral分析，结构分析，结构分析，结构分析，结构分析。这些数据将使调查人员能够将南加州巴斯利斯的岩浆和在中期地壳深度的变形和板型信息联系起来，以解决与扁平型范式相关的相互冲突模型，并在Laramide造口仪的举措以及该奖项的奖励均通过评估了Intelpriac and Infectiac and Intellial and Infectiac。

项目成果

Mesozoic Fabric Influence on the formation and geometry of the Quaternary Cucamonga Fault

中生代构造对第四纪库卡蒙加断层的形成和几何形状的影响

• 发表时间: 2022
• 期刊: Southern California Earthquake Center abstracts
• 作者: Francine Robles, Joshua Schwartz

Constraining the timing and conditions of magmatism and metamorphism in the lower crust of the Southern California batholith using U-Pb zircon geochronology and Ti-in-zircon thermometry

利用 U-Pb 锆石年代学和钛锆石测温法约束南加州岩基下地壳岩浆作用和变质作用的时间和条件

• 发表时间: 2022
• 期刊: Geological Society of America Abstracts with Programs
• 作者: Robles, F.;Schwartz, J.;Miranda, E.;Klepeis, K.A.;and Mora-Klepeis, G.
• 通讯作者: and Mora-Klepeis, G.

LATE CRETACEOUS INTRA-ARC TRANSPRESSION AND THRUSTING IN THE SOUTHERN CALIFORNIA BATHOLITH

南加州岩基的白垩纪晚期弧内挤压和冲断

• DOI: 10.1130/abs/2023am-394372
• 发表时间: 2023
• 期刊: Geological Society of America Abstracts with Programs
• 作者: Schwartz, Joshua;Miranda, Elena;Klepeis, Keith;Mora-Klepeis, Gabriela
• 通讯作者: Mora-Klepeis, Gabriela

STYLES AND HISTORY OF CONVERGENT MARGIN DEFORMATION IN THE SOUTHERN CALIFORNIA BATHOLITH DURING THE LATE CRETACEOUS BEGINNING OF THE LARAMIDE OROGENY

晚白垩世拉拉米德造山运动初期南加州岩基收敛边缘变形的类型和历史

• DOI: 10.1130/abs/2023am-394531
• 发表时间: 2023
• 期刊: Geological Society of America Abstracts with Programs
• 作者: Baskin, Jillyan;Klepeis, Keith;Schwartz, Joshua;Miranda, Elena;Robles, Francine;Mora-Klepeis, Gabriela
• 通讯作者: Mora-Klepeis, Gabriela

Late Cretaceous arc flare up and sinistral intra-arc ductile deformation in the southern California batholith, 2022, Late Cretaceous arc flare up and sinistral intra-arc ductile deformation in the southern California batholith

南加州岩基晚白垩世弧耀斑和左旋弧内延性变形，2022年，南加州岩基晚白垩世弧耀斑和左旋弧内延性变形

• 发表时间: 2022
• 期刊: Geological Society of America Abstracts with Programs
• 作者: Schwartz, J.;Lackey, J.S.;Miranda, E.;Klepeis, K.;Mora-Klepeis, G.;Robles, F.;Bixler, J.
• 通讯作者: Bixler, J.