DOI: 10.1038/s41561-017-0022-3
论文题名: Heterogeneous delivery of silicate and metal to the Earth by large planetesimals
作者: Marchi S. ; Canup R.M. ; Walker R.J.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2018
卷: 11, 期: 1 起始页码: 77
结束页码: 81
语种: 英语
Scopus关键词: anomaly
; concentration (composition)
; Earth
; hydrodynamics
; isotopic analysis
; mantle
; metal
; Moon
; planetesimal
; siderophile element
; silicate
; simulation
英文摘要: After the Moon's formation, Earth experienced a protracted bombardment by leftover planetesimals. The mass delivered during this stage of late accretion has been estimated to be approximately 0.5% of Earth's present mass, based on highly siderophile element concentrations in the Earth's mantle and the assumption that all highly siderophile elements delivered by impacts were retained in the mantle. However, late accretion may have involved mostly large (≥ 1,500 km in diameter) - and therefore differentiated - projectiles in which highly siderophile elements were sequestered primarily in metallic cores. Here we present smoothed-particle hydrodynamics impact simulations that show that substantial portions of a large planetesimal's core may descend to the Earth's core or escape accretion entirely. Both outcomes reduce the delivery of highly siderophile elements to the Earth's mantle and imply a late accretion mass that may be two to five times greater than previously thought. Further, we demonstrate that projectile material can be concentrated within localized domains of Earth's mantle, producing both positive and negative 182W isotopic anomalies of the order of 10 to 100 ppm. In this scenario, some isotopic anomalies observed in terrestrial rocks can be explained as products of collisions after Moon formation. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/105640
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Southwest Research Institute, Boulder, CO, United States; Deptartment of Geology, University of MD, College Park, MD, United States
Recommended Citation:
Marchi S.,Canup R.M.,Walker R.J.. Heterogeneous delivery of silicate and metal to the Earth by large planetesimals[J]. Nature Geoscience,2018-01-01,11(1)