Off-axis Sills of Guaymas Basin: Implications for Thermogenic-carbon Flux of a Sedimented Rift Basin

该项目将进行为期10.5天的巡航，收集Guaymas盆地一大片离轴海底的深拖曳侧扫声纳和chirp海底剖面数据、CTD测量数据、水样和TowCam图像，以确定流体和天然气的排放区域。这项工作将验证一个假设，即Guaymas盆地富含碳的流体和气体的大量排放是由离轴岩浆侵入富有机质沉积物驱动的热反应引起的。这些数据将识别水深和亚底特征，如土丘、凹痕和断层，这些特征表明了现在和过去的喷口；成像和拍摄高后向散射特征，如细菌垫、自生碳酸盐或指示流体通量的生物群落；并通过对水样的分析，提供一种方法来区分离轴沉积脊环境中甲烷和其他碳氢化合物的生物源和热源。这项工作支持IODP Birth of Oceans Mission Proposal和IODP Proposal 658 Full，该提案与北大西洋解体期间的储层生产和甲烷生成有关。这一努力将有助于了解全球碳循环的源和汇，这是过去和现在气候变化的一个强大强迫函数。该项目通过国立大学Autónoma的Bill Bandy博士和Carlos Mortera博士的参与促进国际合作，并通过两名美国和两名墨西哥研究生参与研究考察和随后的分析促进教育。

This is a project to conduct a 10.5-day cruise to collect deep-towed sidescan sonar and chirp sub-bottom profile data, CTD measurements, water samples, and TowCam imagery over a large region of the off-axis seafloor in Guaymas Basin in order to identify areas of venting fluid and gas. This work will test the hypothesis that substantial venting of carbon-rich fluid and gas occurs off axis in Guaymas Basin as a result of thermogenic reactions driven by off-axis magmatic intrusion into organic-rich sediments.These data will identify bathymetric and sub-bottom features such as mounds, pock marks, and faults that are indicative of present and past venting; image and photograph high backscatter features such as bacterial mats, authigenic carbonate, or biological communities that are indicative of fluid flux; and provide a means, through analysis of water samples, to distinguish between biogenic and thermogenic sources of methane and other hydrocarbons in the off-axis sedimented ridge setting.This work supports IODP Birth of Oceans Mission Proposal and IODP proposal 658 Full related to sill production and methane generation during breakup of N. Atlantic.Broader Impacts This effort will contribute to knowledge of sources and sinks in the global carbon cycle, which is a strong forcing function in past and present climate change. The project promotes international collaboration through the participation of Dr. Bill Bandy and Dr. Carlos Mortera of Universidad Nacional Autónoma de México, and it promotes education through the participation of two U.S. and two Mexican graduate students in the research cruise and subsequent analyses.