List of Titles

Authors: Hanson, E Kelsey , Moore, John M , Bordy, Emese M , Marsh, Julian S , Howarth, Geoffrey H , Robey, Julian van Aardt
Date: 2009
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/144978 , vital:38397 , https://doi.org/10.2113/gssajg.112.2.125
Description: Twelve Group II and fourteen Group I kimberlite diatremes in central South Africa were examined for upper crustal xenoliths in order to estimate the extent of various lithological units of the Karoo Supergroup in the main Karoo basin at times of kimberlite eruption, the Cretaceous erosional history of the area, and the approximate vertical extent of the kimberlite diatremes prior to erosion. Sandstone and amygdaloidal basaltic lava xenoliths from the Karoo Supergroup were specifically selected as their modal mineralogies and geochemical compositions respectively can be attributed to specific stratigraphic positions within the Karoo Supergroup. Results indicated that, at the time of Group II kimberlite eruption (120 Ma), basaltic lavas of the Drakensberg Group covered the entire area, but by the time of Group I kimberlite eruption (85 Ma), they were restricted to the south-eastern half of the study area.
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Date Issued: 2009

Authors: Hanson, E Kelsey , Moore, John M , Robey, Julian van Aardt , Bordy, Emese M , Marsh, Julian S
Date: 2006
Language: English
Type: text , long abstracts
Identifier: http://hdl.handle.net/10962/132144 , vital:36804
Description: The estimation of post-emplacement kimberlite erosion in South Africa through the study of upper-crustal xenoliths is relatively unexplored; however the presence of these xenoliths has been recognized for well over a 100 years. Previously postemplacement erosion levels of a small number of kimberlite pipes have been inferred through the study of the degree of country-rock diagenesis, the depth of sill formation and the depth of the initiation of diatreme facies kimberlite.
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Date Issued: 2006

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