Geochemistry of the Brent Crater, Canada

Student thesis: Master's Thesis

Abstract

Characterization of the alteration present at the Brent impact structure, revealed at least the presence of a chloritization, Au-depletion and K-enrichment process in the melt-fragment breccias. While this totally scattered the mobile Ni, Co and Cr, the immobile PGE are not affected. Also the melt lens shows alteration, albeit to a lesser degree. Ni, Co and Cr still have a strong correlation here. The use of the Os isotope system delivered a meteorite contribution up to 1 a 2 wt.% for the deepest melt lens sample. Together with the moderately and siderophile elements, it rejects the possibility of a fractionation during post-impact cooling, as suggested by Evans et al. [1993], and implicates an impact identification.
We also reject the assumption of Grieve [1978] and Palme et al. [1981] that no (ultra)mafic components are present. However, if present, they can only be responsible for (a part of) the Ni, Co and Cr scatter in the melt-fragment breccias. The melt lens is for certain not affected. A more regional target rock study should be conducted to examine the possibility of (ultra)mafic components and their effect on the melt-fragment breccias.
Date of Award2011
Original languageEnglish
SupervisorPhilippe Claeys (Promotor)

Keywords

  • Brent crater

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