Chemical Interactions Between Gabbros and Their Host Rocks: Field and Laboratory Studies of the Tertiary Macrodikes of the Kangerdlugssuaq Area, East Greenland

格陵兰东部Kangerdlugssuaq地区的第三纪辉长岩岩脉为研究基性岩浆与岩块结合时发生的化学和物理过程提供了一个自然实验室实验的产物。极好的冰川高山露头，1公里的构造起伏，以及对野外关系和火成岩岩石学的良好背景研究（包括Wager， Deer和其他人关于Skaergaard侵入岩的经典研究）使这里成为一个理想的研究区域。应该有可能对大规模化学污染和选择性化学污染这两种相互竞争的假设进行明确的检验。化学相互作用的机制和混合岩浆的作用机制可以通过对丰富的、非常干净的露头的直接观察来确定。建议采用野外、地球化学、同位素和实验等多学科方法，对辉长岩被活化的唾液基底和热液蚀变的玄武岩围岩选择性污染的假设进行验证。地球化学数据将用于评价现有的同化-分馏结晶模型，并在必要时改进这些模型。这些结果将有助于理解地壳污染的物理和化学过程，这一过程对于准确解释大陆火山岩的地球化学特征以及由此推断次大陆地幔的性质至关重要。

The Tertiary gabbroic dikes of the Kangerdlugssuaq region, East Greenland, offer for study the products of a natural laboratory experiment on the chemical and physical processes that occur when mafic magmas incorporate blocks of wall rocks. A combination of superb glaciated alpine outcrops, structural relief of 1 km, and good background studies of field relations and igneous petrology (including the classic work of Wager, Deer, and others on the Skaergaard Intrusion) make this an ideal study area. It should be possible to make a definitive test of the competiting hypotheses of wholesale vs. selective chemical contamination. The mechanisms of chemical interaction and mechanics of mixing hybrid magmas may be determined by direct observation of the abundant, remarkably clean outcrops. It is proposed to use a multi-disciplinary array of methods including field, geochemical, isotopic, and experimental techniques to test the hypothesis that gabbros were selectively contaminated by remobilized sialic basement and hydrothermally altered basalt wall rocks. The geochemical data will be used to evaluate existing models of assimilation - fractional crystallization and to refine such models, if necessary. The results should materially aid understanding the physics and chemistry of crustal contamination, a process essential to the accurate interpretation of geochemical characteristics of continental volcanic rocks and consequent deductions regarding the nature of subcontinental mantle.