Collaborative Research: The Rosario Segment of the Cretaceous Alisitos Oceanic Arc (Baja California, Mexico): An Outstanding Field Analog to the Izu Bonin Arc

合作研究：白垩纪阿利西托斯大洋弧的罗萨里奥段（墨西哥下加利福尼亚州）：与伊豆博宁弧的杰出野外模拟

• 批准号: 1545676
• 负责人: Cathy Busby
• 金额: $ 24.23万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1545676&HistoricalAwards=false
• 关键词: Collaborative; Research; Rosario; Segment; Cretaceous

This collaborative research project will interface closely with the IODP projects in the Izu-Bonin-Mariana (IBM) arc by fully characterizing what is probably its best field analog on Earth: the Rosario segment of the Alisitos arc. DeBari has been deeply involved in the IBM proposals, and Busby is co-chief scientist on IODP Expedition 350. Exhumed rocks from arc crustal sections have the unique ability to inform studies of active subduction zones by "ground-truthing" the assumptions that go into models, experiments, and interpretive geophysics and geochemistry. Some of the questions we will ask, highly complementary to the IBM work, are: How is arc middle crust constructed? What is the relationship and proportion between volcanic and plutonic rocks in juvenile arc crust? What is the tempo of constructing arc crust? How does arc crust composition change with time? Is there any older crust that makes up significant parts of the Alisitos arc? What can we learn about convergent margin mineralization by comparing the Alsitos arc to the Izu Bonin arc? How does the crustal structure of the Alisitos arc compare with seismic velocity profiles in modern arcs? Can surface and borehole heat flow measurements in modern arcs be related to features preserved in the geologic record of ancient arcs?This research furthers the careers of two female scientists (DeBari at WWU and Busby at UCSB) and their respective graduate students. Training of these graduate students is collaborative so that both students will become skilled at the integration of field geology, petrology and geochronology. Scientific interaction between US scientists at WWU and UCSB and international colleagues at UNAM in Mexico will broaden the perspectives of all participants, and enhance research and training outcomes. The proposed project is of interest to the broader science community, as it addresses some of the foremost questions in the NSF GeoPRISMS science plan on the growth and evolution of continental crust through study of island arcs (http://www.geoprisms.org/science-plan.html#science-plan), as well as research envisioned by the GeoPRISMS ExTerra initiative (http://www.geoprisms.org/scd/exterra.html). One of the main products, a web-based 'Island Arc Crust Virtual Field Model', will be used by scientists as a reference model for IBM drilling outcomes, and in curriculum for both undergraduate and graduate students. A field workshop in the Alisitos arc, ideally held in conjunction with Expeditions 350-352 post-expedition meetings and before IBM-4 drilling begins, will provide invaluable context for IBM drilling participants.The Rosario segment of the Cretaceous Alisitos arc in Baja California is an outstanding field analog for the Izu-Bonin-Mariana (IBM) volcanic arc. The IBM arc is under intense study by the International Ocean Drilling Program (IODP) as an in-situ example of present-day formation of nascent continental crust. Earth is the only planet in the solar system with extensive felsic (Si-rich, Mg-poor) continental crust. The rocky planets and the Moon have basaltic (Mg-rich) crusts formed early in the history of the solar system. The volume of continental crust on Earth has grown over time due to plate tectonic processes, dominantly because of accretion of felsic to intermediate volcanic arcs at convergent margins. However, the processes that produce this felsic to intermediate crust are not well characterized in situ. The Rosario segment has superior three-dimensional exposures of an upper- to middle-crustal section through an extensional oceanic arc. Previous mapping of this 60-km-long segment of the Alisitos arc, done in the 1990?s (Busby et al., 2006), will provide a framework for the proposed study; however, that study focused mainly on field descriptions of the volcanic rocks, with limited geochronology, and no geochemistry. The proposed study will determine in detail the relationships between rock types at all stratigraphic levels in the arc, using field, geochemical, and geochronological data. This collaborative research project will interface closely with IODP Expeditions 350-352 (in 2014) and a fourth ambitious proposal to drill to the arc middle crust (IODP Proposal 698 at site IBM-4, awaiting scheduling. These data will be used to construct an 'Island Arc Crust Virtual Field Model' to be used by scientists as a reference model for IBM drilling outcomes.

该协作研究项目将与Izu-Bonin-Mariana（IBM）ARC中的IODP项目紧密接触，以充分表征它可能是地球上最好的田野模拟：Alisitos Arc的Rosario段。 Debari一直深入参与IBM的提案，Busby是IODP Expedition 350的共同主持科学家。弧形地壳部分的挖掘岩石具有独特的能力，可以通过“地面流动”的假设来为主动俯冲带的研究提供信息，这些假设是模型，实验，实验，解释性地球物理学和地理物理学和地理物理学和地理物理学和地理学。我们将提出的一些问题与IBM工作相辅相成，是：如何构建中弧中的地壳？少年弧形地壳中的火山和丘陵岩之间的关系和比例是什么？建造弧形地壳的节奏是什么？弧形结构成分如何随时间变化吗？是否有构成Alisitos弧的重要部分的较旧的外壳？通过将Alsitos Arc与Izu Bonin弧进行比较，我们可以了解什么？ Alisitos弧的地壳结构与现代弧中的地震速度曲线相比如何？现代弧的表面和井眼热流量测量是否与古代弧的地质记录中保存的特征有关？这项研究进一步推进了两位女科学家（WWU的Debari和UCSB的Busby）及其各自的研究生的职业。对这些研究生的培训是合作的，因此两个学生都将熟练地融入现场地质，岩石学和地球学。美国WWU和UCSB的美国科学家与墨西哥UNAM的国际同事之间的科学互动将扩大所有参与者的观点，并增强研究和培训成果。拟议的项目吸引了更广泛的科学界，因为它解决了NSF Geoprisms Science中最重要的问题，即通过研究Island Arcs（http://wwwwwwwwww.geoprisms.org/science-plan-plan.html.html#science-plan），对大陆地壳的增长和进化的研究，并驱动了GEORTRIST。 （http://www.geoprisms.org/scd/exterra.html）。 主要产品之一是基于网络的“岛弧形虚拟现场模型”，科学家将用作IBM钻探结果的参考模型，并在本科生和研究生的课程中。 Alisitos Arc的一次实地研讨会，理想情况下，与探险队结合350-352爆发后会议，在IBM-4钻探开始之前，将为IBM钻探参与者提供宝贵的背景。弧。国际海洋钻井计划（IODP）是IBM ARC的深入研究，作为当今新生大陆地壳形成的原位例子。地球是太阳系中唯一具有广泛的长英质（Si-Rich，Mg-poor）大陆壳的行星。岩石行星和月亮在太阳系历史上早期形成了玄武岩（MG富含）地壳。 由于板块构造过程，地球上大陆壳的体积随着时间的推移而增加，这主要是因为在收敛缘处将长英质到中间火山弧化为中间火山弧。但是，产生这种长毛的过程到中间地壳的原位表征并未得到很好的特征。罗萨里奥（Rosario）段通过延伸的海洋弧进行上层至中心截面的三维暴露。以前在1990年代进行的60公里长的Alisitos Arc的映射（Busby等，2006）将为拟议的研究提供一个框架；但是，该研究主要集中在火山岩的现场描述上，地质学有限，没有地球化学。拟议的研究将详细确定弧形，地球化学和地球文量学数据的岩石类型之间的岩石类型之间的关系。该协作研究项目将与IODP Expeditions 350-352（2014年）和第四个雄心勃勃的建议（在IBM-4上的IODP提案698）进行钻探（IODP提案698），等待日程安排。这些数据将用于构建'Island Arc Collust Virtual Field Models for Scielder drirans drirans drirans drirans Irliand Models IBM IBS Inler Inrermists IB。