Collaborative Research: Tectonic and Magmatic Implications of a Mid-Crustal, Sheeted Complex in a Tilted Arc Section, California

合作研究：加利福尼亚州倾斜弧段中地壳片状杂岩的构造和岩浆影响

• 批准号: 0809003
• 负责人: Andrew Barth
• 金额: $ 10.62万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0809003&HistoricalAwards=false
• 关键词: Collaborative; Research; Tectonic; Magmatic; Implications

A sheeted plutonic complex exposed within a tilted mid-crustal section in the eastern Transverse Ranges of California, including Joshua Tree National Park (JTNP), will be examined in detail. The section provides a wonderful opportunity for analysis of (1) the depth dependent physical changes in, and growth of, a magma plumbing system; (2) the relative importance of source region heterogeneity, contamination, and in situ crystal-liquid fractionation in forming compositional diversity in plutonic systems, and (3) the role of mid-crustal detachments and/or vertical deformation partitioning in forming orogen-scale sheeted plutonic complexes. Field mapping and detailed structural analyses combined with geochronology and geochemistry of intrusive units will allow testing of a series of hypotheses. One goal is to determine whether upper and lower crustal plutons and the underlying sheeted complex formed synchronously and thus reflect an abrupt depth-dependent change in petrogenesis and intrusive style during continental margin arc construction. They will also test the hypotheses that the complex represents both a zone of magma transfer, with the creation of vertical pathways, and a site for hybridization that formed magmas parental to upper crustal plutons and explosive volcanic rocks. The goal is to expand our understanding of orogenesis along plate boundaries in the middle and deeper parts of continental crust. This study will dramatically affect our knowledge of vertical changes in the physical and chemical processes operating in magmatic plumbing systems that feed volcanoes. The research will be concentrated within the boundaries of JTNP and will have important positive impact on public education through geoscience outreach and interpretive activities. Over the last five years, the PIs have developed collaborations with Park Service staff at JTNP and with its interpretive arm, the Desert Institute. They will work with the Park and the U.S. Geological Survey to complete a geologic map and improve understanding of the Park?s geology, with a focus on major events in the volcanic and structural evolution that influenced formation of the Park?s landscape. Further outreach will extend that commitment through development of field trips and lectures, and will translate the results to assist park staff in enhancing public educational and curriculum materials. At USC and IUPUI graduate and undergraduate education in the geosciences will be strengthened through exceptional field, classroom and laboratory experiences, including excellent opportunities for underrepresented student groups.

将详细研究加州横贯山脉东部一个倾斜的中地壳剖面内出露的席状深成杂岩，包括约书亚树国家公园（JTNP）。 这一部分提供了一个极好的机会，分析（1）深度依赖的物理变化，和增长，岩浆管道系统;（2）源区非均匀性、混染和原地晶液分馏在形成深大系统成分多样性中的相对重要性，（3）中地壳构造变形和垂直变形分异作用在造山带规模席状深成杂岩形成中的作用。实地测绘和详细的结构分析，结合地质年代学和侵入单元的地球化学，将允许测试一系列假设。 一个目标是确定是否上，下地壳岩体和下席状复杂的同步形成，从而反映了突然的深度依赖性变化的岩石成因和侵入风格在大陆边缘弧建设。他们还将测试这样的假设，即该复合体既代表了一个岩浆转移区，创造了垂直通道，也代表了一个杂交点，形成了上地壳深成岩和爆炸性火山岩的岩浆母体。其目的是扩大我们对大陆地壳中部和深部沿着板块边界的造山作用的理解。 这项研究将极大地影响我们对供给火山的岩浆管道系统中物理和化学过程垂直变化的认识。 研究将集中在JTNP的范围内，并将通过地球科学推广和解释活动对公众教育产生重要的积极影响。 在过去的五年里，PI与JTNP的公园管理局工作人员及其解释部门沙漠研究所开展了合作。他们将与公园和美国地质调查局合作，完成地质图，提高对公园的了解？的地质，重点是火山和结构演变的主要事件，影响了公园的形成？的景观。 进一步的外联活动将通过开展实地考察和讲座来扩大这一承诺，并将成果转化为协助公园工作人员加强公共教育和课程材料。 在南加州大学和IUPUI研究生和本科教育在地球科学将通过特殊的领域，课堂和实验室经验，包括代表性不足的学生群体的良好机会加强。