澳大利亚西部太古代科马提岩和我国鞍山TTG岩石146Sm-142Nd和147Sm-143Nd同位素综合研究

研究地球早期分异和演化历史，是解读现代地球不同圈层相互作用和过程机制以及行星形成和演化的基础，是目前前沿地球科学中最具有挑战性的课题。太古代科马提岩和科马提质玄武岩是地幔大比例部分熔融的产物，直接记录了其形成时期的地幔热状态和化学结构。早太古代-中太古代(Ca.3.8-2.7 Ga)TTG岩石记录了早期壳-幔分异、大陆地壳形成和分异、古老克拉通岩石圈地幔的形成等重要地质事件。因此，太古代科马提岩和相关TTG岩石是地球早期分异和演化的关键研究对象。本次研究试图通过短半衰期146Sm-142Nd和长半衰期147Sm-143Nd同位素分析，结合常规岩石地球化学手段重建太古代地幔元素、同位素和热状态随时间的演化规律。本次工作将推动地球早期分异和演化的研究，加深对地球动力学过程和地球化学不均一性之间关系的理解，从而回答何种因素导致了目前观察到的不同储库的独特地球化学特征。

Deciphering the primordial differentiation and evolution history of the early Earth is one of the most significant challenges in the Earth Sciences and a key to understanding the present day interactions between different Earth's layers in our dynamic Earth System, as well as providing a significant benchmark for understanding planet formation. The Archean Eon (2.5 Ga to nearly 4.0 Ga before the present) was a time that preserved the direct evidence related to the differentiation of early silicate Earth. The Archean komatiites and associated rocks are an ideal target to address issue of the Earth's early differentiation and evolution. Komatiite and komatiitic basalts were produced by high-degree melting of Earth mantle and are confined almost exclusively to the Archean. They directly record the thermal state and chemical structure of deep Earth. Early-Middle Archean TTG also preserved the direct information related to early mantle-crust differentiation, continental crust growth and differentiation, and formation of continental cratonic mantle. Thus, deciphering the primordial differentiation and evolution history of the early Earth is required integrating komatiite and TTG records. The main goal of this project is to decipher the primordial differentiation of Earth mantle its effect on shaping the Earth's chemical architecture through reconstructing the trace elemental, isotopic, and thermal secular evolution of Archean mantle by integrated study of short-lived (146Sm-142Nd) and long-lived (147Sm-143Nd) isotopes with chemical analysis. The work will develop a new conceptual understanding of the timing, processes, and products of primordial differentiation of Earth mantle, creating breakthroughs in understanding interaction between geodynamical processes and chemical variations, and thus what controls the resulting observed geochemical signatures.