...Francis H. Brown; Bereket Haileab; Ian McDougall Abstract This paper describes a sequence of tuffs between the KBS and the Chari Tuff of Omo Group formations in Kenya and Ethiopia. These tuffs have recently been shown to be 1.87 ± 0.02 Ma and 1.38 ± 0.03 Ma in age, respectively. The sequence...

... the Chari Tuff is particularly notable for its wealth of hominid fossils and archaeological sites. Silicic tuffaceous horizons have provided the basis for stratigraphic subdivision and correlation. Pumice clasts within the tuffs contain anorthoclase phenocrysts, ideal for 40 Ar/ 39 Ar single-crystal dating...

.... Stratigraphically higher tuffs and their ages include the Ninikaa Tuff, 3.06 ± 0.03 Ma; the KBS Tuff, 1.88 ± 0.02 Ma; the Malbe Tuff, 1.86 ± 0.02 Ma; the Chari Tuff, 1.39 ± 0.02 Ma, and the Silbo Tuff, 0.74 ± 0.01 Ma, near the top of the sequence. The geochronology and geological data indicate at least three...

...Fig. 8. Composite 40 Ar/ 39 Ar dataset from Chari/Tuff L samples showing eruption age estimates calculated using several statistical approaches. The nMAD plus ‘gap’ algorithm method (e.g. Deino et al. 2019 ) typically gives the oldest estimates, followed by Model 3 (normality test...

... as those sedimentary strata which lie between the basal contact of the Suregei Tuff complex and the upper contact of the prominent tuff exposed along the Ileret Ridge, here named the Chari Tuff, or the basal contact of the Holocene grey tuffaceous predominantly lacustrine siltstones which represent a late...

... the Ileret Tuff Complex near 1.50 ± 0.04 Ma ( Table 2 ), and four others lie between the Ileret Tuff Complex and the Chari Tuff. Estimated ages range from 1.41 to 1.45 Ma for this latter group ( Table 2 ). Another specimen, KNM-ER 807, lies 1.9 m below a lenticular tuff that is compositionally...

... SPECIES OF ACICULARIA FROM THE JURASSIC OF CUTCH AJIT KUMAR PAL Department of Botany, Upiversity of Calcutta AND SUKOMAL GANGOPADHYAYA Department of Geology, Jadavpur University, Calcutta Introduction: The material for the present work was collected from the Chari formation developed at the Jura Dome near...

... and the Bongor Basin will be referred to as the central African subsystem basins, following Genik (1993) . The general area in which the three described trends converge is northeastern Nigeria and the drainage basins of the Chari and Logone Rivers ( Fig. 2 ). The rifts share a common history commencing...

.... Talwara; H. Kalinjra; 9. Parsola-Amhav; 10. Chari-Manpura; 1 1 . I k d a w a l ; 12. Salumbar; 13. Anjcni; 14. Pipalkhunt. prcscnt a1 thc: cslrcmc wcslcl-n cnci ol' ltlc Maximum 11;lkr: size notcd is 4 m m by 2mm. studied lrrcii (1:ig. 1). 'Il~cassocialcd rnincriiis :irc gocthitc, limonilc, 'L'hc...

.... , Haileab , B. & McDougall , I. 2006 . Sequence of tuffs between the KBS Tuff and the Chari Tuff in the Turkana Basin, Kenya and Ethiopia . Journal of the Geological Society, London , 163 , 185 – 204 . Butzer , K.W. , 1971 . The Lower Omo Basin: Geology, fauna and hominids...

... Formation. The chronostratigraphic framework of the Koobi Fora Formation is based on more than 130 tuffs that are isochronous markers and in some cases suitable for isotopic dating. The formation is subdivided into eight members with major tuff layers acting as separating geologic units. The Burgi Member...