Hf-W chronology of early solar system processes

从太阳系中第一批固体的形成到行星体的形成只持续了几百万年(Myr)。在这一短暂的时间间隔内发生的物理和化学过程为太阳系早期行星的起源和演化创造了条件。为了重建这些过程，至关重要的是获得非常精确的年龄，以确定真实事件的发生时间，或提供有关过程速率的信息。这种高精度的年龄可以用短寿命的同位素获得，如182Hf，衰变到182W(t1/2~9Myr)。由于Hf和W的地球化学性质，衰变系统非常适合于在任何尺度上限制金属形成或硅金属平衡的时间。该项目的一个主要目标将是获得不同球粒陨石群以及中菱铁矿和球粒陨石形成的高精度年龄(±1Myr或更高)。由于球粒陨石并不是太阳系中最古老的物体，因此它们在太阳系的化学和矿物学演化中的作用也就不那么清楚了。因此，我们计划为球粒形成过程(ES)建立一个绝对时间框架，并将其与太阳系前10年期间发生的其他分化过程联系起来。

The time interval from formation of the first solids in the solar system to the formation of planetesimals lasted only a few million years (Myr). The physical and chemical processes that occurred during this brief interval set the conditions for the origin and evolution of the planets in the early solar system. To reconstruct these processes, it is essential to obtain very precise ages that date real events or that provide information on the rates of processes. Such high precision ages can be obtained with shortlived isotopes, such as 182Hf, which decays to 182W (t1/2 ~9 Myr). Due to the geochemical properties of Hf and W, the decay system is ideally suited to constraining the time of metal formation or silicatemetal equilibration at any scale. A major goal of this project will be to obtain highly precise ages (±1 Myr or better) for the formation of different chondrite groups as well as mesosiderites and pallasites. Because it is now well established that chondrites are not the oldest objects in the solar system, their role in the chemical and mineralogical evolution of the solar system has become less clear. Therefore, we plan to construct an absolute time frame for the chondrule-forming process(es) and relate this to other differentiation processes that occurred during the first 10 Myr of our solar system.