Tracking the migration of the Indian continent using the carbonate clumped isotope technique on Phanerozoic soil carbonates
نویسندگان
چکیده
Approximately 140 million years ago, the Indian plate separated from Gondwana and migrated by almost 90° latitude to its current location, forming the Himalayan-Tibetan system. Large discrepancies exist in the rate of migration of Indian plate during Phanerozoic. Here we describe a new approach to paleo-latitudinal reconstruction based on simultaneous determination of carbonate formation temperature and δ(18)O of soil carbonates, constrained by the abundances of (13)C-(18)O bonds in palaeosol carbonates. Assuming that the palaeosol carbonates have a strong relationship with the composition of the meteoric water, δ(18)O carbonate of palaeosol can constrain paleo-latitudinal position. Weighted mean annual rainfall δ(18)O water values measured at several stations across the southern latitudes are used to derive a polynomial equation: δ(18)Ow = -0.006 × (LAT)(2) - 0.294 × (LAT) - 5.29 which is used for latitudinal reconstruction. We use this approach to show the northward migration of the Indian plate from 46.8 ± 5.8°S during the Permian (269 M.y.) to 30 ± 11°S during the Triassic (248 M.y.), 14.7 ± 8.7°S during the early Cretaceous (135 M.y.), and 28 ± 8.8°S during the late Cretaceous (68 M.y.). Soil carbonate δ(18)O provides an alternative method for tracing the latitudinal position of Indian plate in the past and the estimates are consistent with the paleo-magnetic records which document the position of Indian plate prior to 135 ± 3 M.y.
منابع مشابه
Paleoelevation Reconstruction using Pedogenic Carbonates
Paleoelevation reconstruction using stable isotopes, although a relatively new science, is making a signifi cant contribution to our understanding of the recent growth of the world’s major orogens. In this review we examine the use of both light stable isotopes of oxygen and the new “clumped-isotope” (Δ47) carbonate thermometer in carbonates from soils. Globally, the oxygen isotopic composition...
متن کامل“Clumped-isotope” geochemistry—The study of naturally-occurring, multiply-substituted isotopologues
Clumped isotope geochemistry is concerned with the state of ordering of rare isotopes in natural materials. That is, it examines the extent to which rare isotopes (D, C, N, O, etc.) bond with or near each other rather than with the sea of light isotopes in which they swim. Abundances of isotopic ‘clumps’ in natural materials are influenced by a wide variety of factors. In most cases, their conc...
متن کاملEstimating Cambro-Ordovician seawater temperature and isotopic composition using carbonate clumped isotope paleothermometry on calcitic and phosphatic fossils
متن کامل
Clumped isotope analysis of carbonates: comparison of two different acid digestion techniques.
RATIONALE The kinetic nature of the phosphoric acid digestion reaction enables clumped isotope analysis of carbonates using gas source isotope ratio mass spectrometry (IRMS). In most laboratories acid digestions are performed at 25°C in sealed vessels or at 90°C in a common acid bath. Here we show that different Δ47 results are obtained depending on the digestion technique employed. METHODS S...
متن کاملClumped isotope thermometry of carbonatites as an indicator of diagenetic alteration
We measure the clumped isotopic signature of carbonatites to assess the integrity of the clumped isotope paleothermometer over long timescales (10–10 years) and the susceptibility of the proxy to closed system re-equilibration of isotopes during burial diagenesis. We find pristine carbonatites that have primary oxygen isotope signatures, along with a Carrara marble standard, do not record clump...
متن کامل