Melt Inclusions in Zircon (and other accessory minerals)

bodnar /SinhaZircon （ZrSiO4）是大多数花岗岩类岩石中常见的辅助矿物。花岗岩中的锆石晶体通常含有岩浆结晶生长过程中形成的熔融包裹体结晶。锆石一般在30 ~ 250微米之间，熔体包裹体在20 ~ 120微米之间。初步的主要元素和微量元素分析表明，熔体包裹体保存了岩浆的化学成分，并提供了传统的大块岩石分析难以获得的信息。熔体包裹体的化学性质将用于评价岩浆从源岩熔融（产生母岩浆）到岩浆最终结晶的化学演化过程。反过来，这些信息将被用来推断岩浆的历史，以及地壳在结晶过程中熔体所经历的化学变化。在熔融和结晶过程中，一些元素对形成的结晶矿物有亲和力，而另一些元素对熔融阶段有亲和力。我们将利用熔融包裹体和共存的锆石化学特征，为推测类花岗岩体成因提供新的微量元素划分数据。初步结果表明，从难熔矿物中的熔体包裹体中获得的分配数据，作为微型天然高压釜，可能优于在短时间实验室实验中获得的数据。初步的主要元素和微量元素数据表明，锆石中的熔体包裹体保存了原始的熔体成分。然而，这些成分往往与从大块岩石分析中推断出的岩浆成分不一致。这种差异的调和将是拟议研究的主要焦点。

EAR-0001168Bodnar/SinhaZircon (ZrSiO4) is a common accessory mineral present in most granitoid rocks. Zircon crystals from granitoid rocks often contain crystallized melt inclusions trapped during crystal growth from a magma. The zircons typically range from 30 to 250 um and the melt inclusions range from 20 to 120 um. Preliminary major and trace element analyses suggest that the melt inclusions preserve magma chemistries and provide information not easily attainable by traditional bulk rock analyses. The chemistry of the melt inclusions will be used to assess chemical evolution of magmas from melting of source rocks (to produce parental magmas) to final crystallization of magmas. This information, in turn, will be used to infer magma histories and the chemical changes that a melt undergoes during crystallization in the earth's crust. During melting and crystallization, some elements have an affinity for the crystalline minerals that form, whereas other elements have an affinity for the melt phase. We will use the melt inclusion and co-existing zircon chemistries to provide new partitioning data for various trace elements which are commonly used to infer petrogenesis of grantitoid rocks. Preliminary results indicate that partitioning data obtained from melt inclusions in refractory minerals, acting as miniature natural autoclaves, may be superior to data obtained in during short-duration laboratory experiments. Preliminary major and trace element data suggests that melt inclusions in zircon preserve original melt compositions. However, these compositions often disagree with magma compositions inferred from bulk rock analyses. Reconciliation of this discrepancy will be a main focus of the proposed research.