RUI/Collaborative Research: Batholiths: Generation and Evolution of Crust in Continental Magmatic Arcs

RUI/合作研究：岩基：大陆岩浆弧中地壳的生成和演化

• 批准号: 0310011
• 负责人: Margaret Rusmore
• 金额: $ 26.85万
• 依托单位: Occidental College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0310011&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Batholiths; Generation

0310011RusmoreThe goal of this project is to establish the existence or absence of mafic-ultramafic roots to batholiths and whether such roots can reconcile the fundamentally basaltic nature of mantle magmatism with the intermediate average composition of the crust. Two hypotheses are considered: 1) that the dense ultramafic residue founders into the mantle leaving the intermediate crustal compositions above, or 2) the residue exists below the Moho and is seismologically indistinct from mantle peridotite. The PIs will use a combination of petrology, geochemistry and geochronology on the plutons of the Central Coast Range Batholith to track changes in source, depth of origin through time and seismic and gravity data to image the present state of the lithosphere. The Central Coast Range Batholith (CCRB) in British Columbia is a very good location for this study. It is a very large batholith which is relatively young and has not had a protracted tectonic history. It's rugged topography gives access to depth profiles of 20 to 25 km.

这个项目的目标是确定镁铁质-超镁铁质岩根的存在或不存在，以及这些岩根是否能使地幔岩浆活动的基本玄武岩性质与地壳的中等平均成分相一致。考虑了两种假设：1)致密的超镁铁质残留物进入地幔，留下上面的中间地壳成分；2)残留物存在于莫霍面以下，在地震学上与地幔橄榄岩不明显。PIS将结合岩石学、地球化学和地质年代学对中央海岸山脉岩基的深成岩浆进行追踪，以追踪来源、起源深度随时间的变化，以及地震和重力数据，以成像岩石圈的当前状态。不列颠哥伦比亚省的中央海岸山脉岩基(CCRB)是进行这项研究的非常好的地点。它是一个非常大的岩基，相对年轻，没有漫长的构造历史。它崎岖的地形使其可以到达20到25公里的深度剖面。