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

这项研究将增进对伴随大陆地壳向海洋地壳过渡的过程的了解，而加州湾是研究这一过渡的最佳地点之一。最近对加州湾的成像揭示了有关裂谷历史和向海底扩张过渡的新信息。然而，只有直接采样才能提供年龄模型，岩性和化学成分，因为墨西哥湾海底的大部分地区缺乏明确的磁异常特征。PI最初的疏浚巡航恢复了与旧大陆地壳有关的各种岩石类型，预先存在的弧和同生裂谷火山活动，包括古老的玄武岩。将这些样本放入地质框架中，将需要为连续采样和多波束测深巡航计划的详细采样类型。这项研究将大大推进我们对加州湾裂谷系岩浆史的理解，并就几个重要问题提供见解：火山岩的来源如何横向和时间变化，以及这与地幔过程的关系;火山作用和岩浆作用如何影响裂谷运动学。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，与圣地亚哥博物馆建立联系，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MARGINS社区使用。

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.