Microdiamonds in ultrahigh-pressure metamorphic rocks

作者：Ogasawara Y^*

来源：Elements, 2005, 1(2): 91-96.

DOI：10.2113/gselements.1.2.91

• microdiamond
• ultrahigh-pressure metamorphism
• continental collision
• Kokchetav

Since the first report of microdiamonds of metamorphic origin in crustal rocks of the Kokchetav Massif, northern Kazakhstan, diamonds have been described from several other ultrahigh-pressure (UHP) metamorphic terranes. In situ diamond is the best indicator of ultrahigh-pressure conditions (> 4 GPa), and testifies to subduction of continental crust to depths within the diamond stability field followed by relatively rapid exhumation In contrast to other UHP terranes, the Kokchetav Massif contains rocks with unusually abundant diamonds, particularly in the Kumdy-Kol region. Kumdy-Kol diamonds exhibit diverse morphologies, dependent upon the host rock. Raman and cathodoluminescence spectra and carbon isotope compositions differ between core and rim, indicating two distinct growth stages.

• 出版日期2005-3