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

在加利福尼亚横贯山脉东部倾斜的地壳中，包括约书亚树国家公园（JTNP）在内的一个片状深成复合体将被详细研究。本节提供了一个很好的机会来分析(1)岩浆管道系统中随深度变化的物理变化和生长；(2)源区非均质性、污染和原位晶液分馏在形成深部构造成分多样性中的相对重要性；(3)中地壳分离和/或垂直变形分割在形成造山带级片状深部杂岩体中的作用。野外测绘和详细的构造分析结合地质年代学和侵入单元的地球化学，将允许对一系列假设进行测试。目的之一是确定上、下地壳岩体和下伏片状杂岩是否同步形成，从而反映大陆边缘弧构造期间岩石成因和侵入样式的深度依赖性突变。他们还将测试这样一种假设，即这个复杂的地方既代表了岩浆转移区，形成了垂直通道，也代表了杂交的地方，形成了上层地壳岩体和爆炸性火山岩的岩浆母岩。目的是扩大我们对大陆地壳中部和深部板块边界造山作用的理解。这项研究将极大地影响我们对火山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5年里，ppi与JTNP的公园管理局工作人员及其解释机构沙漠研究所建立了合作关系。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。它的地质学，重点是影响公园形成的火山和结构演化中的重大事件。年代的景观。进一步的推广将通过开展实地考察和讲座来扩大这一承诺，并将把结果转化为协助公园工作人员改进公共教育和课程材料。在USC和IUPUI，地球科学的研究生和本科教育将通过特殊的实地、课堂和实验室经验得到加强，包括为未被充分代表的学生群体提供极好的机会。

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.