OXYGEN, CARBON, AND STRONTIUM ISOTOPE GEOCHEMISTRY OF DIAMOND-BEARING CARBONATE ROCKS FROM KUMDY-KOL, KOKCHETAV MASSIF, KAZAKHSTAN
- DSpace Home
- →
- Геология России
- →
- ELibrary
- →
- View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.
OXYGEN, CARBON, AND STRONTIUM ISOTOPE GEOCHEMISTRY OF DIAMOND-BEARING CARBONATE ROCKS FROM KUMDY-KOL, KOKCHETAV MASSIF, KAZAKHSTAN
Ohta M.; Ogasawara Y.; Mock T.; Rumble D.
xmlui.dri2xhtml.METS-1.0.item-citation:
Lithos, 2003, 70, 3-4, 77-90
Date:
2003
Abstract:
Diamond-bearing carbonate rocks from Kumdy-Kol, Kokchetav massif, Kazakhstan, were strongly altered by fluids flowing through fractures and infiltrating along grain boundaries during exhumation. Alteration includes retrogradation of high-grade silicate assemblages by hydrous minerals, replacement of diamond by graphite and of dolomite by calcite. Diamond-bearing carbonate rocks are among the most intensely altered isotopically with δ18OVSMOW values as low as +9‰, δ13CVPDB=−9‰, and 87Sr/86Sr as high as 0.8050. Evidence of isotopic equilibration between coexisting dolomite and high-Mg calcite during ultrahigh-pressure metamorphism (UHPM) is preserved only rarely in samples isolated from infiltrating fluids by distance from fractures. Isotopic heterogeneity and isotopic disequilibrium are widespread on a hand-specimen scale. Because of this lack of homogeneity, bulk analyses cannot provide definitive measurements of 13C/12C fractionation between coexisting diamond and carbonate. Our study adequately documents alteration on a scale commensurate with observed vein structures. But, testing the hypothesis of metamorphic origin of microdiamonds has not fully succeeded because our analytical spatial resolution, limited to 0.5 mm, is not small enough to measure individual dolomite inclusions or individual diamond crystals.
Files in this item
This item appears in the following Collection(s)
-
ELibrary
Метаданные публикаций с сайта https://www.elibrary.ru
Related items
Showing items related by title, author, creator and subject.
-
Chen Bin; Sun Keke; Huang Chao; Gu Haiou (Федеральное государственное бюджетное учреждение науки Институт земной коры Сибирского отделения Российской академии наук, 2017)
-
Chekhovich P.A.; Zhivkovich A.Ye.; Medvedovskaya N.I.; Stepanova N.A. (1990)The isotopic makeup of carbon in marine carbonates exhibits quasiperiodic variations in time. Since these changes were controlled by the global balance of organic and carbonate carbon in the oceans, reliably dated isotope ...
-
Makhotin, Mikhail; Ivanov, Vladimir (PANGAEA, 2018-10-18)Boundary position of the Barents Sea between the North Atlantic and the Arctic basin causes a high degree of impact processes occurring in it and on the weather and climate in Northern Eurasia. The most important role in ...
Search DSpace
Browse
-
All of DSpace
-
This Collection