Guaymas Basin Stratigraphy, Event Bed Origins, and Correlation: Maximizing Results from the 4 km of Core Recovered on IODP Expedition 385

大洋盆地的形成和生长经历了大陆裂谷和海底扩张的构造过程。加利福尼亚州海湾(GOC)是地球上少数几个可以通过海底钻探获得年轻洋盆的沉积物填充和火山产物的地方之一。然后，可以从回收的沉积岩芯中研究盆地历史。这项研究的重点是最近在墨西哥中部GOC瓜伊马斯盆地钻探和勘探中发现的约4公里的沉积岩心。这些将被分析和解释，以找出是什么控制了沉积物的组成，沉积物是如何运输和沉积的，以及如何在钻探地点之间匹配沉积层。这项研究帮助培训妇女和少数族裔在地球科学方面的代表性不足，支持一个由三名硕士研究生组成的研究小组，由两名女教授指导。工作成果将通过圣莫尼卡山国家游乐区的外联活动向公众传播。这个位置是美国最大的城市公园。该项目团队将创建新的地质实地考察材料，帮助游客了解公园地质。实地考察将包括露头，其海相沉积岩和火山岩与瓜伊马斯盆地发现的类似。国际大洋发现计划385岩芯的岩相和岩相分析，以及与先前的深海钻探项目LEG钻探成果的结合，是揭示瓜伊马斯盆地泥沙输送和堆积规律及其控制的必要步骤。这一盆地分析的组成部分是潜在基准面、火山灰和其他沙质事件(风暴、地震)层的定义，这些定义可以确定整个盆地在时间上可联系的沉积物包，以显示沉积物堆积率的模式。在385探险中新发现的火山灰和火山碎屑砂-粉砂层将使用各种岩相学和成像技术进行指纹识别，并通过对其主元素和次要元素地球化学以及矿物相的元素组成的分析进一步证明其来源。深盆地中的砂质重力物质流层将显示出指示其输送机制的相态和碎屑模式，例如：A)三角洲前缘洪水和物质损耗；B)地震引起的大陆斜坡上的物质损耗；C)热带风暴冲刷海岸沉积物。这项研究与其他探险385研究相结合，将使瓜伊马斯盆地成为世界上研究得最好的年轻洋盆，并成为新生洋盆早期沉积史的模型。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Ocean basins form and grow through the tectonic processes of continental rifting followed by seafloor spreading. The Gulf of California (GOC) is one of few places on earth where the sediment fill and volcanic products of a young ocean basin can be obtained through seafloor drilling. Then, the basin history can be studied from recovered sediment cores. The focus of this study is ~4 km of sediment cores recovered during recent drilling and exploration of the Guaymas Basin, Central GOC, Mexico. These will be analyzed and interpreted to find out what controlled the sediment composition, how the sediment was transported and deposited, and how to match the sedimentary layers among drill sites. This study helps to train women and underrepresented minorities in geoscience, supporting a research team of three master’s degree students mentored by two female professors. The work results will be communicated to the public through outreach activities in the Santa Monica Mountains National Recreation Area. This location is the largest urban park in the United States. The project team will create new geologic field-trip materials to help visitors learn about park geology. The field-trip stops will include outcrops with marine sedimentary and volcanic rocks similar to those found in the Guaymas Basin. Lithofacies and petrofacies analyses of International Ocean Discovery Program Expedition 385 cores and integration with prior Deep Sea Drilling Project Leg 64 drilling results are necessary steps for unraveling the patterns and controls of sediment delivery and accumulation in the Guaymas Basin. Integral to this basin analysis is the definition of potential datums, volcanic ashes and other sandy event (storm, seismic) beds, that can define packages of sediment that are linkable in time across the basin, to show patterns in sediment accumulation rates. Ash and epiclastic volcanic sand-silt beds newly discovered on Expedition 385 will be fingerprinted using a variety of petrographic and imaging techniques, and their provenance further documented using analyses of their major and minor element geochemistry, and elemental composition of mineral phases. Sandy gravity-mass flow beds in the deep basin will show facies and detrital mode patterns indicative of their delivery mechanisms, for example: A) delta-front flood and mass-wasting; B) seismic-induced mass wasting along the continental slope; and C) tropical storm flushing of coastal sediment. This study, in combination with other Expedition 385 research, will make the Guaymas Basin arguably the best studied young ocean basin in the world and a model for the early sedimentary history of nascent ocean basins.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.