The submarine magmatic record of the transition from arc magmatism to continental rifting and seafloor spreading at the Gulf of California MARGINS focus site

加利福尼亚湾边缘焦点地点从弧岩浆活动过渡到大陆裂谷和海底扩张的海底岩浆记录

• 批准号: 0646563
• 负责人: Peter Lonsdale
• 金额: $ 39.24万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-12-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0646563&HistoricalAwards=false
• 关键词: submarine; magmatic; record; transition; arc

The study will improve the understanding of processes that accompany the transition from continental to oceanic crust, and the Gulf of California provides one of the most accessible locations for studying this transition. Recent imaging of the Gulf of California reveals new information about the rifting history and transition to sea floor spreading. However, only direct sampling will be able to provide the age models, lithology and chemistry as much of the Gulf seafloor lacks clear magnetic anomaly signatures. An initial cruise of dredging by the PIs recovered a variety of rock types related to older continental crust, the preexisting arc and synrift volcanism, including older basalts. Placing these samples in geologic framework will require the type of detailed sampling planned for an ROV sampling and multibeam bathymetry cruise. The research will significantly advance our understanding of the magmatic history of the Gulf of California rift system, and provide insights regarding several significant issues: how the source of the volcanic rocks has varied laterally and temporally and how this relates to processes in the mantle; and how the volcanism and magmatism has affected the rift kinematics. The broader impacts include strong international collaboration; development of a project web site for research dissemination to community and public, links to the San Diego Museum, and training of two graduate students. The project will collect an important suite of samples for the use of the broader MARGINS community.

这项研究将提高人们对从大陆地壳到海洋地壳过渡过程的理解，而加利福尼亚湾为研究这种过渡提供了最容易到达的地点之一。最近对加利福尼亚湾的成像揭示了裂谷历史和向海底扩张过渡的新信息。然而，只有直接取样才能提供年龄模型、岩性和化学成分，因为海湾海底大部分地区缺乏明确的磁异常特征。在最初的疏浚巡航中，勘探队发现了与更古老的大陆地壳、先前存在的弧和叠带火山作用有关的各种岩石类型，包括更古老的玄武岩。将这些样品放置在地质框架中需要ROV采样和多波束测深巡航的详细采样计划。这项研究将极大地促进我们对加利福尼亚湾裂谷系统岩浆历史的理解，并提供关于几个重要问题的见解：火山岩的来源如何在横向和时间上发生变化，以及这与地幔过程的关系；以及火山活动和岩浆活动对裂谷运动学的影响。更广泛的影响包括强有力的国际合作；开发一个项目网站，向社区和公众传播研究成果，连接圣地亚哥博物馆，并培训两名研究生。该项目将收集一套重要的样本，供更广泛的边际社区使用。