A new trial to search for isotopically anomalous osmium and ruthenium in fine-grained Ca, Al-rich Allende inclusions by radiochemical neutron activation analysis

	A new trial to search for isotopically anomalous osmium and ruthenium in fine-grained Ca, Al-rich Allende inclusions by radiochemical neutron activation analysis
	Liu, YZ; Chai ZF(柴之芳); Chai, CF
刊名	CHEMICAL GEOLOGY
	1997
卷号	141 期号:1-2 页码:#REF!
关键词	allende inclusion osmium ruthenium isotopic anomaly radiochemical neutron activation analysis
通讯作者	Liu, YZ (reprint author), UNIV ELECTROCOMMUN,DEPT APPL PHYS & CHEM,1-5-1 CHOFUGAOKA,CHOFU,TOKYO 182,JAPAN.
英文摘要	The ratios of Os-184/Os-190 and Ru-96/Ru-102 in five fine-grained Ca, Al-rich Allende inclusions (CAIs) were determined simultaneously and precisely by radiochemical neutron activation analysis (RNAA). The results show that their deviations relative to the terrestrial chemical reagent are within -1.5% and 1.9% for Os-184/Os-190 and Ru-96/Ru-102, respectively. It seems unlikely that the isotopic anomalies of Os and Ru exist at a magnitude of more than +/- 2% in bulk fine-grained Allende CAIs. Whereas the possibility that the fine-grained Allende CAIs measured in this work do not contain presolar components and thus have normal isotopic compositions cannot be excluded, we believe that our data may most plausibly be interpreted as the anomalies carried by submicron-size metal alloys thought to be the presolar grains were homogenized during the processes of sample digestion and chemical separation. Os and Ru concentrations in five fine-grained CAIs were determined by comparison with the activities of the known amounts of Os and Ru standards, respectively. In contrast to the coarse-grained Allende CAIs, Os and Ru were greatly depleted in these five fine-grained CAIs. The mean enrichment factors of Os and Ru relative to Cl chondrite were 2.82 and 2.99, respectively. In addition, Os is depleted relative to Ru in four of five fine-grained Allende CAIs, and a large fractionation between Os and Ru is observed. The Cl chondrite-normalized Os/Ru enrichment factor ranges from 0.23 to 2.50 in five fine-grained Allende CAIs. These results support the non-equilibrium incomplete condensation model for the origin of fine-grained Allende CAIs. It suggests that the fine-grained Allende CAIs probably contain much less hcp alloy grains, and thus the primordial signatures of isotope and Os/Ru ratio might more readily survive the equilibrium process than those in coarse-grained Allende CAIs. Consequently, it is undeniable that the fine-grained Allende CAI is one of the most promising hunting grounds to search for isotopically anomalous Os and Ru. (C) 1997 Elsevier Science B.V.
学科主题	Geochemistry & Geophysics
类目[WOS]	Geochemistry & Geophysics
收录类别	SCI
WOS记录号	WOS:A1997XZ81200008
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/226182]
专题	高能物理研究所_院士
推荐引用方式 GB/T 7714	Liu, YZ,Chai ZF,Chai, CF. A new trial to search for isotopically anomalous osmium and ruthenium in fine-grained Ca, Al-rich Allende inclusions by radiochemical neutron activation analysis[J]. CHEMICAL GEOLOGY,1997,141(1-2):#REF!.
APA	Liu, YZ,柴之芳,&Chai, CF.(1997).A new trial to search for isotopically anomalous osmium and ruthenium in fine-grained Ca, Al-rich Allende inclusions by radiochemical neutron activation analysis.CHEMICAL GEOLOGY,141(1-2),#REF!.
MLA	Liu, YZ,et al."A new trial to search for isotopically anomalous osmium and ruthenium in fine-grained Ca, Al-rich Allende inclusions by radiochemical neutron activation analysis".CHEMICAL GEOLOGY 141.1-2(1997):#REF!.