TRR 170: Late Accretion onto Terrestrial Planets

合作研究中心TRR 170的主要主题是了解类地行星的后期增长历史，从上一次与月球大小的巨大碰撞到火星大小的行星胚胎，再到随后的较小天体的后期轰炸，TRR 170的主要主题是了解类地行星的后期生长历史。这一行星形成时期对于理解类地行星的形成和它们的化学分化，以及限制控制它们随后演化的参数至关重要。为了解决这些问题，并提高我们目前对45亿至38亿年前地球、月球和其他类地行星晚期成长史的理解，TRR 170采用了一种多学科方法，结合了地球化学和岩石学、遥感和行星地质学以及地球动力学和撞击模型方面的专业知识。TRR170‘S研究计划将提供对晚期吸积的时间和速率、化学预算和地球动力学影响的新见解，并将约束这一时间间隔内的物理化学边界条件。具体地说，我们将(1)限制月球盆地形成撞击的时间和分布，以改善内太阳系陨石坑动力学的基本参数，(2)量化45亿至38亿年前吸积物质的质量、来源和化学成分，(3)确定这些物质的成分在吸积撞击和岩浆脱气过程中是如何改变的，(4)评估吸积物质如何分布在不断增长的类地行星中，以及它如何改变它们随后的演化，以及(5)建立类地行星热演化的定量模型，包括相应时间段内岩浆海洋、地壳和早期大气的形成和相互作用。这些综合结果将细化我们对陆源行星早期演化过程中几个关键过程的零碎理解，例如巨型撞击在挥发损失过程和核心形成中的作用、岩浆海洋的发展和演化、向固态对流的转变、化学和同位素不均匀的均质以及类地行星的冷却历史。除了科学目标之外，TRR170‘S专门的综合研究生课程还将培养下一代行星科学家，特别强调现代行星科学的多学科特征。

The major theme of the collaborative research centre TRR 170 'Late Accretion onto Terrestrial Planets' is to understand the late growth history of the terrestrial planets, from the last giant collisions with Moon- to Mars-sized planetary embryos to the subsequent late bombardment with smaller objects. This period of planet formation is critically important for understanding the formation of the terrestrial planets and their chemical differentiation, and for constraining the parameters that controlled their subsequent evolution. To address these questions and improve our current understanding of the late growth history of the Earth, its Moon, and other terrestrial planets from 4.5 to 3.8 billion years ago, TRR 170 applies a multidisciplinary approach that combines expertise in geochemistry and petrology, remote sensing and planetary geology, and geodynamic and impact modelling. TRR 170's research programme will provide novel insights into the timing and rates, chemical budget, and geodynamic implications of late accretion and will constrain the physicochemical boundary conditions during this time interval. Specifically, we will (1) constrain the timing and distribution of basin-forming impacts on the Moon to improve basic parameters of the cratering chro-nology in the inner solar system, (2) quantify the mass, provenance and chemical composition of accreted materials between 4.5 and 3.8 billion years ago, (3) determine how the compositions of these materials were modified during accretionary impacts and magma degassing, (4) assess how accreted material was distrib-uted within the growing terrestrial planets and how it changed their subsequent evolution, and (5) develop quantitative models for the thermal evolution of the terrestrial planets, including the formation of and interac-tion between magma oceans, crust and early atmospheres in the relevant time interval. The combined results will refine our fragmentary understanding of several key processes during the early evolution of the terrestri-al planets, such as the role of giant impacts in volatile loss processes and core formation, the development and evolution of magma oceans, the transition to solid-state convection, homogenization of chemical and isotopic heterogeneities, and the cooling history of the terrestrial planets. Besides its scientific goals, TRR 170's dedicated integrated graduate programme will educate the next generation of planetary scientists, with a particular emphasis on the multidisciplinary character of modern planetary sciences.