Mathematics – Logic
Scientific paper
Dec 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992lmip.conf...44k&link_type=abstract
In Lunar and Planetary Inst., International Conference on Large Meteorite Impacts and Planetary Evolution p 44 (SEE N93-10112 01
Mathematics
Logic
Geochemistry, Hypervelocity Impact, Meteorite Collisions, Mineralogy, Precambrian Period, Republic Of South Africa, Spherules, Swaziland, Condensates, Core Sampling, Igneous Rocks, Neutron Activation Analysis, Platinum, Rocks, Shales
Scientific paper
The Barberton Greenstone belt is a 3.5- to 3.2-Ga-old formation situated in the Swaziland Supergroup near Barberton, northeast Transvaal, South Africa. The belt includes a lower, predominantly volcanic sequence, and an upper sedimentary sequence (e.g., the Fig Tree Group). Within this upper sedimentary sequence, Lowe and Byerly identified a series of different beds of spherules with diameters of around 0.5-2 mm. Lowe and Byerly and Lowe et al. have interpreted these spherules to be condensates of rock vapor produced by large meteorite impacts in the early Archean. We have collected a series of samples from drill cores from the Mt. Morgan and Princeton sections near Barberton, as well as samples taken from underground exposures in the Sheba and Agnes mines. These samples seem much better preserved than the surface samples described by Lowe and Byerly and Lowe et al. Over a scale of just under 30 cm, several well-defined spherule beds are visible, interspaced with shales and/or layers of banded iron formation. Some spherules have clearly been deposited on top of a sedimentary unit because the shale layer shows indentions from the overlying spherules. Although fresher than the surface samples (e.g., spherule bed S-2), there is abundant evidence for extensive alteration, presumably by hydrothermal processes. In some sections of the cores sulfide mineralization is common. For our mineralogical and petrographical studies we have prepared detailed thin sections of all core and underground samples (as well as some surface samples from the S-2 layer for comparison). For geochemical work, layers with thicknesses in the order of 1-5 mm were separated from selected core and underground samples. The chemical analyses are being performed using neutron activation analysis in order to obtain data for about 35 trace elements in each sample. Major elements are being determined by XRF and plasma spectrometry. To clarify the history of the sulfide mineralization, sulfur isotopic compositions are being determined.
Boer Rudolf H.
Koeberl Christian
Reimold Wolf Uwe
No associations
LandOfFree
Early Archean spherule beds of possible impact origin from Barberton, South Africa: A detailed mineralogical and geochemical study does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Early Archean spherule beds of possible impact origin from Barberton, South Africa: A detailed mineralogical and geochemical study, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Early Archean spherule beds of possible impact origin from Barberton, South Africa: A detailed mineralogical and geochemical study will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1138422