The Ferrar Magmatic Mush Column System, Dry Valleys, Antarctica

该奖项由极地计划办公室南极地质和地球物理计划提供，支持通过对南极费拉尔集团岩床的研究来研究岩浆结晶过程。地球的基本结构是通过涉及岩浆或熔融岩石结晶的过程形成的。数十亿年来，这些过程的运作产生了各种各样的岩石类型，这些岩石类型反过来又形成了地球的基本表面特征，即大陆和海洋盆地。然而，这些物理和化学过程的细节在很大程度上仍未被发现。虽然现今的火山活动通过喷发出的熔岩的多样性证实了这一整体的分异过程，但尚不清楚这一戏剧性的最终结果与造成这一结果的长期而详细的深度过程有何关系。曾经深埋在地下，现在由于侵蚀而暴露出来的岩浆凝固体（称为岩体）也提供了证据，但大多数情况下，这些岩体在岩浆火山系统中的背景并不清楚。本研究的目的是通过研究南极洲一组独特地显示这些岩浆过程的岩浆岩，为解决这一基本问题作出重大贡献。它们揭示了深成作用与火山作用之间的关系，可能是理解行星岩浆作用的一个重要关键。南极洲干谷的Ferrar岩浆系统（Ferrar-DV）就是一个例证，它是一个新兴的全球性范例，即一堆岩浆岩席或岩床下面连接着一个深层次的岩浆源，上面连接着一个火山中心。世界上主要的岩浆系统（即，在洋脊，基拉韦厄，Mt.埃特纳、斯蒂尔沃特和朗姆等）也倾向于表现出这种类型的系统，但只有费拉-DV清楚地揭示了深部以糊状物为主的系统与近地表之间的关键物理和化学联系。喷发前岩床体系例如，在最深处，一个广泛的糊状填充的超镁铁质岩床形成了一个小的（400米）层状侵入体，其许多特征与类似成分的最大层状侵入体（如Dufek和Stillwater）相同。往上看，大的斜方辉石（opx）晶体（主要形成泥质岩）和较小的斜长石的逐渐流失导致了分化的拉斑玄武岩岩床。以前广泛的同时代和化学连续的熔岩（柯克帕特里克玄武岩）完成了这个非常完整，异常暴露和广泛（~ 10，000平方公里）的岩浆系统。公里揭示了一堆以冷杉树的四肢和树干的方式相互连接的窗台的雷雨云状填充模式。opx舌记录了一个幕序列的岩床侵位加上脉动填充个别岩床本身。Ferrar-DV系统的表观侵位韵律类似于深成系统和火山系统。此外，虽然分层是普遍存在的，并局限于，opx丰富的舌头，在一个地方（Dais）的层特别好地形成了许多规模（毫米到米），并显示冲刷和填充，涟漪和其他形式的排序。Dais的岩浆体体积相对较小，地壳高度较高，因此可以快速淬火，独特地保留了大型岩浆系统中通常因退火而丢失的结构。主要目标是充分描绘其垂直和水平范围;了解其建立的动力学;了解Dais层状侵入体的形成机制;制作整个干谷的Ferrar岩石地图;并制作Opx舌和馈线系统的3D模型。总的来说，该项目将试图阐明一种罕见的深成系统和火山系统之间的过渡，这很可能对B的行星岩浆活动具有根本性的影响

This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports research on magma crystallization processes through studies of sills of the Ferrar Group in Antarctica.Earth's basic structure came about through processes involving the crystallization of magma or molten rock. The operation of these processes over billions of years has produced a wide diversity of rock types that have in turn given rise to the basic surface features of Earth, namely, continents and ocean basins. Yet the very details of these physical and chemical processes remain largely undiscovered. Although present day volcanism exemplifies this overall process of differentiation through the variety of lava erupted, it is not clear how this dramatic end result relates to the prolonged and detailed processes at depth responsible for this result. Solidified bodies of magma (called plutons), once deeply buried and now exposed through erosion, also furnish evidence, but most often the context of these plutons within the magmatic-volcanic system is not clear. The aim of the present research is to make a significant contribution to solving this fundamental problem by studying a group of magmatic rocks in Antarctica that uniquely display these magmatic processes. They expose the relationship of plutonism to volcanism and may be an important key to understanding planetary magmatism.The emerging global paradigm of a stack of magmatic sheets or sills connected below to a deep-seated magmatic source and above to a volcanic center is exemplified by the Ferrar magmatic system of the Dry Valleys, Antarctica (Ferrar-DV). The world's major magmatic systems (i.e., at ocean ridges, Kilauea, Mt. Etna, Stillwater, and Rum, among many others) tend also to exhibit this style of system, but only the Ferrar-DV clearly reveals the critical physical and chemical connections between the deep, mush-dominated system and the near-surface. pre-eruptive sill system. At the deepest level, for example, an extensive mush-filled, ultramafic sill forms a small (400 m) layered intrusion with many features common to the largest layered intrusions of similar composition such as Dufek and Stillwater. Moving up-section, the progressive loss of large crystals of orthopyroxene (opx), which largely form the mush, and smaller plagioclase leads to differentiated tholeiitic sills. Formerly extensive coeval and chemically contiguous lavas (Kirkpatrick Basalt) complete this remarkably complete, exceptionally exposed, and extensive (~10,000 cubic-km) magmatic system.Previous work in tracing the opx mush tongue over an area of ~3,000 sq.-km has revealed the thunderhead-like filling pattern of a stack of sills interconnected in the fashion of the limbs and trunk of a fir tree. The opx tongue records an episodic sequence of sill emplacement coupled with pulsative filling of the individual sills themselves. The apparent emplacement rhythm of the Ferrar-DV system is akin to both plutonic and volcanic systems. Moreover, although layering is pervasive within, and confined to, the opx-rich tongue, at one locale (the Dais) the layers are particularly well formed on many scales (mm to m) and show scour and fill, ripples and other forms of sorting. The relatively small size and high crustal level of the magma body at the Dais allowed rapid quenching, uniquely preserving textures commonly lost to annealing in large magma systems.This project seeks to ascertain the full physical and chemical nature of the Ferrar-DV magmatic system. The major goals are to delineate fully its vertical and horizontal extent; to understand the dynamics of its establishment; to understand the mechanics of formation of the Dais layered intrusion; to produce a map of Ferrar rocks throughout the Dry Valleys; and to produce a 3-D model of the opx tongue and feeder system. Overall, the project will attempt to elucidate a rarely seen transition between plutonic and volcanic systems, which may well have implications fundamental to planetary magmatism in the b