Th-230 - U-238 series disequilibrium of the Olkaria basalts Gregory Rift Valley, Kenya

Details Th-230 - U-238 series disequilibrium of the Olkaria basalts Gregory Rift Valley, Kenya Th-230 - U-238 series disequilibrium of the Olkaria basalts Gregory Rift Valley, Kenya

Mar 1993

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993lpi....24..121b&link_type=abstract

In Lunar and Planetary Inst., Twenty-fourth Lunar and Planetary Science Conference. Part 1: A-F p 121-122 (SEE N94-12015 01-91)

Computer Science

African Rift System, Basalt, Isotopes, Kenya, Volcanology, Feldspars, Mineralogy, Petrology

Scientific paper

U-Th disequilibrium analyses of the Naivasha basalts show a very small (U-238/Th-230) ratios which are lower than any previously analyzed basalts. The broadly positive internal isochron trend from one sample indicates that the basalts may have source heterogeneities, this is supported by earlier work. The Naivasha complex comprises a bimodal suite of basalts and rhyolites. The basalts are divided into two stratigraphic groups each of a transitional nature. The early basalt series (EBS) which were erupted prior to the Group 1 comendites and, the late basalt series (LBS) which erupted temporally between the Broad Acres and the Ololbutot centers. The basalts represent a very small percentage of the overall eruptive volume of material at Naivasha (less than 2 percent). The analyzed samples come from four stratigraphic units in close proximity around Ndabibi, Hell's Gate and Akira areas. The earliest units occur as vesicular flows from the Ndabibi plain. These basalts are olivine-plagioclase phyric with the associated hawaiites being sparsely plagioclase phyric. An absolute age of 0.5Ma was estimated for these basalts. The next youngest basalts flows occur as younger tuft cones in the Ndabibi area and are mainly olivine-plagioclase-clinopyroxcene phyric with one purely plagioclase phyric sample. The final phase of activity at Ndabibi resulted in much younger tuft cones consisting of air fall ashes and lapilli tufts. Many of these contain resorbed plagioclase phenocrysts with sample number 120c also being clinopyroxene phyric. The isotopic evidence for the basalt formation is summarized.

Affiliated with

Also associated with

No associations

Rating

Th-230 - U-238 series disequilibrium of the Olkaria basalts Gregory Rift Valley, Kenya 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 Th-230 - U-238 series disequilibrium of the Olkaria basalts Gregory Rift Valley, Kenya, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Th-230 - U-238 series disequilibrium of the Olkaria basalts Gregory Rift Valley, Kenya will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1447013