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Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions
Published on: June 13, 2015
Late accretion on the earliest planetesimals revealed by the highly siderophile elements
Christopher W Dale1, Kevin W Burton, Richard C Greenwood
1Department of Earth Sciences, Durham University, Durham DH1 3LE, UK. christopher.dale@durham.ac.uk
Science (New York, N.Y.)
|April 12, 2012
Summary
Late accretion of chondritic material explains the abundance of highly siderophile elements (HSEs) in planetary mantles. This process was common to all differentiated bodies, with oxidation state controlling HSE distribution.
Area of Science:
- Planetary Science
- Geochemistry
- Cosmochemistry
Background:
- The abundance of highly siderophile elements (HSEs) in terrestrial planet mantles is explained by late accretion of chondritic material after core formation.
- Previous studies focused on large bodies like Earth, the Moon, and Mars.
Purpose of the Study:
- To investigate HSE abundances in smaller planetesimals.
- To determine if late accretion of chondritic material was a universal process for differentiated bodies.
- To understand the factors controlling HSE distribution in planetary mantles.
Main Methods:
- Analysis of highly siderophile element (HSE) abundances in smaller planetesimals.
- Comparison of HSE proportions with chondritic material.
- Modeling the influence of parent-body size and oxidation state on HSE distribution.
Main Results:
- Smaller planetesimals also exhibit elevated HSE abundances in chondritic proportions.
- Late accretion of chondritic material occurred across a wide timeframe (≤5 to ≥150 million years after solar system formation).
- Parent-body size influences absolute HSE abundances, while oxidation state is the primary control on HSE mixing into silicate mantles.
Conclusions:
- Late addition of chondritic material was a common process for all differentiated planets and planetesimals.
- The oxidation state of a body is a critical factor in determining the final HSE content of its silicate mantle.
- Understanding these processes provides insights into the early evolution of rocky bodies in the solar system.
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