Late Miocene environmental change in Nepal and the northern Indian subcontinent: Stable isotopic evidence from paleosols

Quade, Jay; Cater, J. M. L.; Ojha, T. P.; Adam, Jon; Harrison, T. Mark

doi:10.1130/0016-7606(1995)107<1381:lmecin>2.3.co;2

Cited by 353 publications

(185 citation statements)

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“…Standard pétrographie analysis was performed on select paleo-CaCOs samples (n = 10) prior to geochemical preparation. As expected for pedogenic carbonate precipitated in the vadose zone (e.g., Cerling, 1984;Quade et al, 1995), micritic calcite was dominant in the thin sections. All carbonate was cleaned and oven dried at 70°C before drilling or grinding.…”

Section: Stable Isotope and Pétrographie Analysessupporting

confidence: 72%

“…Carbon from detrital, previously formed soil, or parent carbonate (e.g., limestone, marble, calcic rocks) may also be present in a soil; but again, high soil CO2 respiration rates from the influx of biogenic CO2 prevent inheritance in discrete, nondisseminated forms of pedogenic CaC03, like those analyzed here. The isotopic composition of hydromorphic and groundwater carbonate may be contaminated by non-plant sources of carbon (Quade et al, 1995;Slate et al, 1996;Quade and Roe, 1999), and are not part of this study. The stratigraphie interval overlying Tuff IB falls within the type section for the Olduvai Subchron, dated from 1.942 to 1.785 Ma (Grommé and Hay, 1971;Tamrat et al, 1995;Lourens et al, 1996;Blumenschine et al, 2003).…”

Section: Carbonate Formationmentioning

confidence: 99%

“…During the past 30 years this method of environmental reconstruction has been applied to early hominin and hominoid localities in East Africa (e.g., Cerling et al, 1977Cerling et al, , 1988Cerling and Hay, 1986;Cerling, 1992;Kingston et al, 1994;Sikes, 1994Sikes, , 1996Sikes, , 2000Sikes et al, 1997Sikes et al, , 1999and summarized in Sikes, 1999), as well as other time periods and areas worldwide (e.g., Quade et al, 1989aQuade et al, , 1995Smith et al, 1993;Alam et al, 1997). Pedogenic carbonate and organic 8^^C values represent many generations of plants, averaged over the lifetime of a soil (hundreds or thousands of years).…”

Section: Soil Stable Isotope Valuesmentioning

confidence: 99%

“…Alhough the continental record is discontinuous and cannot be expected to mirror the marine sedimentary sequence (see Sikes, 1999), stable isotopic studies of paleosols have been correlated with other continental or global proxy records of paleoclimate (Smith et al, 1993;deMenocal, 1995;Quade et al, 1995). Further, lacustrine ecosystems like paleo-Olduvai are most appropriate for such studies because small, closed basins are highly sensitive to climatic fluctuations (e.g., Feibel, 1999).…”

Section: Paleoclimatementioning

confidence: 99%

See 3 more Smart Citations

Stable isotopes of pedogenic carbonates as indicators of paleoecology in the Plio-Pleistocene (upper Bed I), western margin of the Olduvai Basin, Tanzania

Sikes

Ashley

2007

Journal of Human Evolution

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Section: Stable Isotope and Pétrographie Analysessupporting

confidence: 72%

Section: Carbonate Formationmentioning

confidence: 99%

Section: Soil Stable Isotope Valuesmentioning

confidence: 99%

Section: Paleoclimatementioning

confidence: 99%

See 2 more Smart Citations

Stable isotopes of pedogenic carbonates as indicators of paleoecology in the Plio-Pleistocene (upper Bed I), western margin of the Olduvai Basin, Tanzania

Sikes

Ashley

2007

Journal of Human Evolution

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“…Although the timing of onset of C4 expansion varies by location, the major shift in δ 13 C is commonly observed in the very latest Miocene between ∼6-5.5 Ma (7,14,15). This timing is remarkably similar to the timing of the Messinian Salinity Crisis (MSC), in which the Mediterranean Sea shrank and ultimately dried up from 5.96 to 5.33 Ma (16).…”

mentioning

confidence: 87%

Mio-Pliocene aridity in the south-central Andes associated with Southern Hemisphere cold periods

Amidon

Fisher

Burbank

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Although Earth’s climate history is best known through marine records, the corresponding continental climatic conditions drive the evolution of terrestrial life. Continental conditions during the latest Miocene are of particular interest because global faunal turnover is roughly synchronous with a period of global glaciation from ∼6.2–5.5 Ma and with the Messinian Salinity Crisis from ∼6.0–5.3 Ma. Despite the climatic and ecological significance of this period, the continental climatic conditions associated with it remain unclear. We address this question using erosion rates of ancient watersheds to constrain Mio-Pliocene climatic conditions in the south-central Andes near 30° S. Our results show two slowdowns in erosion rate, one from ∼6.1–5.2 Ma and another from 3.6 to 3.3 Ma, which we attribute to periods of continental aridity. This view is supported by synchrony with other regional proxies for aridity and with the timing of glacial ‟cold” periods as recorded by marine proxies, such as the M2 isotope excursion. We thus conclude that aridity in the south-central Andes is associated with cold periods at high southern latitudes, perhaps due to a northward migration of the Southern Hemisphere westerlies, which disrupted the South American Low Level Jet that delivers moisture to southeastern South America. Colder glacial periods, and possibly associated reductions in atmospheric CO2, thus seem to be an important driver of Mio-Pliocene ecological transitions in the central Andes. Finally, this study demonstrates that paleo-erosion rates can be a powerful proxy for ancient continental climates that lie beyond the reach of most lacustrine and glacial archives.

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Reconstructing the Greater Indian margin: A balanced cross section in central Nepal focusing on the Lesser Himalayan duplex

Robinson

Martin

2014

Tectonics

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Across much of the Himalaya, rocks in the Lesser Himalayan duplex are covered by roof thrusts of other Paleoproterozoic Lesser Himalayan rocks or Greater Himalayan rocks. However, in central Nepal, between the Main Central thrust and the Main Boundary thrust, Lesser Himalayan rocks are exposed in structurally complex relationships within the Lesser Himalayan duplex. We present two balanced cross sections with different stratigraphy involved in the duplex, one with the basal Kuncha Formation and one without this unit, to test stratigraphic assumptions. Both cross sections have roof thrust sheets consisting of the Main Central thrust, Ramgarh-Munsiari thrust, and Trishuli thrust folded over the hinterland dipping Lesser Himalayan duplex dissected by late faults. Cross section 1 has a shortening estimate from the Main Central thrust to the Main Boundary thrust, including motion on the Main Central thrust, of 359 km or 78%. Cross section 2 has a shortening estimate of 349 km or 76% over the same region. Because the amount and percentage of shortening are not significantly different between the two cross sections, the different stratigraphic assumptions did not change the shortening results. This similarity suggests that many of the choices made when constructing a cross section may be less important than researchers previously thought.

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Late Miocene environmental change in Nepal and the northern Indian subcontinent: Stable isotopic evidence from paleosols

Cited by 353 publications

References 0 publications

Stable isotopes of pedogenic carbonates as indicators of paleoecology in the Plio-Pleistocene (upper Bed I), western margin of the Olduvai Basin, Tanzania

Stable isotopes of pedogenic carbonates as indicators of paleoecology in the Plio-Pleistocene (upper Bed I), western margin of the Olduvai Basin, Tanzania

Mio-Pliocene aridity in the south-central Andes associated with Southern Hemisphere cold periods

Reconstructing the Greater Indian margin: A balanced cross section in central Nepal focusing on the Lesser Himalayan duplex

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