CHONDRULES

Author:

Hewins Roger H.1

Affiliation:

1. Geological Sciences, Rutgers University, Piscataway, New Jersey 08855-1179

Abstract

▪ Abstract  Chondrules are ∼1-mm igneous droplets in primitive meteorites, and their abundance suggests widespread melting in the protoplanetary disk. Chondrules with relict unmelted grains or igneous rims record multi111ple melting events. There are two main types of chondrules, type I (FeO-poor and volatile-poor) and type II [FeO-rich and approximately chondritic (solar) in composition]. Type I chondrules in the unmetamorphosed chondrite Semarkona show evidence of evaporative loss with regard to the moderately volatile elements. Loss of S produces much of the FeNi metal in chondrules. Though the finest grained type I and II chondrules in Semarkona are both approximately chondritic in bulk composition, they differ in FeO content of olivine, indicating different precursors. Simulations suggest temperatures of chondrule formation of 1550–1900°C, with short (<1 min) heating times. Short-lived isotopes suggest that chondrules formed relatively late, and nebular shock waves are the current favorite heating mechanism. As chondrules were transported to the midplane more easily than fine dust or fluffy aggregates, they were probably important components in building planets.

Publisher

Annual Reviews

Subject

Space and Planetary Science,Earth and Planetary Sciences (miscellaneous),Astronomy and Astrophysics

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3