DOI: 10.1016/j.palaeo.2015.11.030
论文题名: Paleosols and paleoenvironments of the early Miocene deposits near Karungu, Lake Victoria, Kenya
作者: Driese S.G. ; Peppe D.J. ; Beverly E.J. ; DiPietro L.M. ; Arellano L.N. ; Lehmann T.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2016
卷: 443 起始页码: 167
结束页码: 182
语种: 英语
英文关键词: Early Miocene
; East Africa
; Paleo-Vertisol
; Paleoclimate
; Polypedogenesis
; Tropical weathering
英文摘要: A 50. m thick stratigraphic section at Ngira, near Karungu on the shore of Lake Victoria in western Kenya, documents the early Miocene paleoenvironments of the area. The basal Ngira paleosol is a 7.6. m thick, oxisolic Vertisol that formed during a prolonged period of pedogenesis; it began as a smectite-dominated Vertisol that was later overprinted through polypedogenesis to become a kaolinitic paleosol highly depleted of all base cations, with abundant Fe concentrations and depletions, and complexly variegated color mottle patterns that reflect extensive ferruginization. Paleoenvironmental reconstructions using bulk geochemistry indicate warm and wet conditions during development of the Ngira paleosol that probably supported a tropical seasonal forest on a stable upland surface for 10s to 100s of thousands of years. Following this long-lived stable landscape, rapid subsidence, perhaps associated with slip on a high-angle fault associated with the onset or progression of the Nyanza Rift and/or the development and eruptive history of the nearby Kisingiri volcano, buried the paleosol and formed a nascent lake basin that experienced multiple transgressions and regressions. During one interval of regression, fluvial sandstones and conglomerates were deposited along with fluvio-lacustrine sandstones and claystones that include weakly developed paleosols. These weakly-developed paleosols indicate a relatively dry paleoenvironment with seasonal precipitation, and probably a shrubland/bushland or riparian forest habitat. Important terrestrial and aquatic vertebrate fossils are primarily preserved within fluvial and fluvio-lacustrine deposits, indicating that the terrestrial Karungu fauna lived in a relatively dry and open habitat. This study demonstrates polypedogenesis and inferences regarding onset of abrupt tectonic activity in the early Miocene in equatorial eastern Africa, and emphasizes the contrasts between landscape stability of the Ngira paleosol and the poorly developed soils in the fluvio-lacustrine facies. © 2015 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/68593
Appears in Collections: 过去全球变化的重建
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作者单位: Terrestrial Paleoclimatology Research Group, Department of Geology, Baylor University, One Bear Place #97354, Waco, TX, United States; Senckenberg Research Institute, Natural History Museum Frankfurt, Senckenberganlage 25, Frankfurt am Main, Germany
Recommended Citation:
Driese S.G.,Peppe D.J.,Beverly E.J.,et al. Paleosols and paleoenvironments of the early Miocene deposits near Karungu, Lake Victoria, Kenya[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2016-01-01,443