Investigating the relationship between pluton growth and volcanism at an active intrusions in the central Andes

研究安第斯山脉中部活跃侵入岩体生长与火山活动之间的关系

基本信息

批准号：
NE/G01843X/1
负责人：
Joachim Gottsmann
金额：
$ 79.5万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FG01843X%2F1
关键词：
Investigating relationship between pluton growth

项目摘要

How magma is emplaced and interacts with its surrounding rock is of central interest in the Earth Sciences. The intrusion of magma into the Earth's crust plays a major role in the dynamics and the evolution of continental crust. In many cases magmas are funnelled upwards and erupt at volcanoes that dot the Earth's surface, particularly in areas where tectonic plates collide. The Andes are part of such a collision zone where large magma bodies (batholiths) form, due to chemical evolution of intruding deeper magma as well as partial melting of surrounding rocks. A common style of volcanic activity in the Andes is the catastrophic eruption of many hundreds to thousands of cubic kilometres of magma in the form of ignimbrites (volcanic rock containing ash and pumice) which often results in the collapse of the magma chamber roof upon eruption, leaving behind more or less ring-shaped surface depressions with diameters of many kilometres. The project is motivated by results obtained from space-borne satellites indicating ground deformation and significant uplift at in the central Andes at Uturuncu volcano, Bolivia, where magma may be accumulating for 270 thousand years. It is suspected that this inflation is caused by the growth of a large magma body at depth. If this interpretation is correct then these anomalies provide an outstanding opportunity to answer questions such as how large magma bodies are assembled in the crust to form plutons, how they evolve, how they relate to volcanism in general and how they manifest at the Earth's surface, potentially before eruption. We aim to find answers to these questions via a coordinated, integrated approach across various disciplines of the Earth Sciences. Central to this ambitious project lies the amalgamation of geodesy, geophysics, geology, petrology and mathematical modelling to document pluton growth in real time. The implications of the proposed work include assessing the role of plutons in continental dynamics and the potential for large volcanic eruptions. We requests funds for the UK component of a collaborative UK-US project, which also involves partners from Spain, Chile and Bolivia. We propose an integrated investigation of the Uturuncu uplift to test the hypothesis that pluton growth is occurring, to document the dynamics of growth, and to explore the links between plutonism, volcanism and tectonics. The core of the study will be a geophysical experiment over a 4-year period to study the ground deformation, mass changes and seismicity, and to image the sub-surface structure beneath the volcano. The geophysical experiment will be complemented by geological and petrological investigations as well as mathematical modelling to set the geophysical experiment in the context with igneous processes and the long-term magmatic evolution. A key outcome of the research will be a new generation of mathematical models to inform on how large magma chambers grow and which geodetic or geophysical signals we might expect to record at the Earth's surface. We will quantify the nature of the sources responsible for ground inflation by separating the contributions of shallow migration of (hot) water and gases, and deep magma replenishment and ponding, to geophysical signals. We are also interested to find out where these reservoirs are located, how many there are and how they relate to the depth of magma chambers that have led to eruptions in the volcano's past. For the latter, lava morphology studies and petrology will give insights onto the conditions in these magma chambers. We aim at developing advanced models of magma systems embedded in continental crust incorporating complexities such as variable mechanical properties of the crust, plastic deformation of deeper crust as well as the influence of crystallization of gas-saturated magma and shallow hydrothermal systems on ground deformation.

岩浆的融合方式并与周围岩石相互作用是地球科学中的核心利益。岩浆侵入地球地壳中，在大陆地壳的动力学和演变中起着重要作用。在许多情况下，岩浆在地球表面的火山上向上汇合并爆发，尤其是在构造板碰撞的地区。安第斯山脉是这样一个碰撞区的一部分，由于化学进化，侵入更深的岩浆以及周围岩石的部分融化，大型岩浆体（沐浴岩）形成。安第斯山脉中一种常见的火山活动风格是数百至数千立方公里的岩浆的灾难性喷发，以igi木（火山岩含有灰烬和浮石的火山岩）的形式发生，通常会导致岩浆腔室屋顶的崩溃，爆发，喷发时崩溃留下或多或少的环形表面凹陷，直径为许多公里。该项目是由从太空传播的卫星获得的结果激励的，该卫星表明地面变形和玻利维亚乌图鲁姆木火山中部的中央安第斯山脉的明显隆升，那里的岩浆可能积累了270万年。人们怀疑这种通胀是由深度大岩浆体的生长引起的。如果这种解释是正确的，那么这些异常提供了一个很棒的机会来回答问题，例如在地壳中组装大型岩浆物体以形成岩石，它们的发展方式，它们与火山症的关系一般以及它们如何在地球表面上表现出来，可能在喷发前。我们的目标是通过在地球科学的各个学科中的协调，集成的方法来找到这些问题的答案。这个雄心勃勃的项目的核心是地球，地球物理学，地质学，岩石学和数学建模的融合，以实时记录pluton的生长。拟议工作的含义包括评估岩石在大陆动力学中的作用以及大型火山喷发的潜力。我们要求为英国UK-US项目的英国组成部分提供资金，该项目还涉及西班牙，智利和玻利维亚的合作伙伴。我们提出了对UTURUNCU隆升的综合研究，以检验plut子生长发生的假设，以记录生长的动态，并探索丘脑，火山和构造学之间的联系。该研究的核心将是一个在4年期间研究地面变形，质量变化和地震性，并成像火山下的地下结构的地球物理实验。地质和岩石学研究以及数学模型将补充地球物理实验，以在火成岩过程和长期岩浆进化的情况下将地球物理实验设置为地球物理实验。这项研究的关键结果将是新一代的数学模型，以告知我们可能希望在地球表面记录的大型岩浆生长以及哪些地球物理信号。我们将通过将（热）水和气体的浅层迁移以及深层岩浆补充和思考的浅层迁移的贡献分离为地球物理信号来量化负责地面充气的来源的性质。我们还有兴趣找出这些水库的位置，有多少种以及它们与导致火山爆发的岩浆腔深度的关系。对于后者，熔岩形态研究和岩石学将洞悉这些岩浆腔的条件。我们旨在开发嵌入大陆壳中的岩浆系统的先进模型，这些模型结合了复杂性，例如地壳的可变机械性能，更深的地壳的塑性变形以及气体饱和岩浆和浅水热系统对地面变形的结晶的影响。