strontium isotopes equatorial

The area of apparent advection includes the eastern part of the equatorial high-productivity zone and part of the Guatemala Basin. We attempted to find links between …

The strontium isotope system includes radiogenic (87 Sr/ 86 Sr) and stable (88 Sr/ 86 Sr) isotopes. The radiogenic Sr isotope ratio ( 87 Sr/ 86 Sr) is a tracer for oceanic Sr input fluxes from weathering and hydrothermal processes (Blum & Erel, 1995 ; Capo & Depaolo, 1990 ).

The element strontium has four naturally occurring isotopes: 84 Sr, 86 Sr, 87 Sr, and 88 Sr. Only 87 Sr is radiogenic – produced by the β-decay of 87 Rb with a half-life of 48.8 billion years. The most abundant strontium isotope is 88 Sr, making up approximately 83% of naturally occurring strontium; followed by 10% 86 Sr, 7% 87 Sr and 1% 84 Sr. In …

Strontium-isotope and trace-metal ratios of 180 soil-water and 18 surface-water sites in the Southern Colorado Plateau have revealed possible source areas for some of 37 archaeological corn cobs ...

THE strontium isotope ratio in sea water is influenced by climate, tectonics, weathering and hydrothermal activity at ocean ridges l -4 • Its evolution through time, determined …

The sulfur isotope ratio (δ34S) recorded in marine barite is commonly used to estimate secular changes in the sulfur isotopic composition of seawater sulfate (δ34 S SO4) throughout Earth's history. The Cenozoic record demonstrates a drastic 5‰ increase in seawater δ 34 S SO4 during the Early Eocene. However, the gradient of this excursion ...

The strontium-isotope data of the deep sea sediments are plotted against the Rb/Sr ratio in Fig. 1; for reference in this figure is a 500 m.y. isochron with an arbitrary initial Sr^/Sr86 ratio of 0-704. ... In the Equatorial Atlantic strikingly high concentration ofkaolinite, attributed to latite weathering products transported by the Amazon ...

Dissolution of barite for the analysis of strontium isotopes and other chemical and isotopic variations using aqueous sodium carbonate. Chemical Geology: Isotope Geoscience Section, 52 (3–4), ... Benthic Ba fluxes in the central Equatorial Pacific, implications for the oceanic Ba cycle. Earth and Planetary Science Letters, 142 (3–4), 439–50.

Dissolution of barite for the analysis of strontium isotopes and other chemical and isotopic variations using aqueous sodium carbonate. Chemical Geology: Isotope Geoscience Section, 52 (3–4 ...

Seawater 87 Sr/ 86 Sr ratios have been used as a proxy for continental weathering flux and the partial pressure of atmospheric CO 2 (pCO 2) in Earth's past, but the fidelity of 87 Sr/ 86 Sr records in marine carbonates under diagenesis remains controversial. To investigate this issue, we undertook an integrated chemostratigraphic …

Of the four stable strontium isotopes found in nature, the isotope 88 Sr is the most common nuclide with a proportion of over 82%. Sr-87 enters nature as a stable decay product of the radioactive rubidium isotope Rb-87. Atomic Mass m a: Quantity: Half-life: Spin: Strontium Isotopic mixture: 87,62 u: 100 %: Isotope 84 Sr: 83,913419(8) u:

New and existing strontium isotope data are given for several widespread evapo-rites from western equatorial Pangea. The data indicate evaporite deposition occurred on proximal margins of the Gulf ...

1 EditorialBuilding from a session we chaired at the 2019 International Union for Quaternary Research Congress in Dublin, this research topic explores advances and new applications in strontium isotope research across palaeoecology, archaeology, and allied fields. These contributions encompass the range of current research, the latest …

Donald J Depaolo. B. L. Ingram. The isotopic ratio of strontium-87 to strontium-86 shows no detectable variation in present-day ocean water but changes slowly over millions of years. The strontium ...

A strontium isotope baseline of Cyprus. Assessing the use of soil leachates, plants, groundwater and surface water as proxies for the local range of bioavailable strontium isotope composition. Science of The Total Environment, Vol. 708, Issue., p. 134714.

Strontium atoms are those having 38 protons in the nucleus. They may also have from 46–50 neutrons, and thus strontium atoms can possess a range of atomic weights – 84, 86, 87, and 88 – depending upon the number of neutrons. The natural abundances of these isotopes are 0.56%, 9.86%, 7.0%, and 82.58%, respectively.

A composite strontium isotopic seawater curve was constructed for the Miocene between 24 and 6 Ma by combining 87 Sr/ 86 Sr measurements of planktonic foraminifera from Deep Sea Drilling Project sites 289 and 588. Site 289, with its virtually continuous sedimentary record and high sedimentation rates (26 m/m.y.), was used for constructing the …

The strontium contained in carbonate shells of marine organisms records the ratio of strontium-87 to strontium-86 of the oceans at the time that the shells form. Sedimentary rocks composed of accumulated fossil carbonate shells can be dated and correlated with the use of high precision measurements of the ratio of strontium-87 to strontium-86 ...

Strontium isotopes (87 Sr/ 86 Sr) are commonly used to assess the age of Cenozoic dolostones found on many isolated oceanic islands.The possible influence of Rubidium (Rb) content on the 87 Sr/ 86 Sr ratios, however, has generally been ignored. This critical issue is assessed by examining the 87 Sr/ 86 Sr ratios and elements (Rb, Sr, Al, Ti and K) of …

Sr isotopes were analyzed using wet plasma and the time resolved analysis (TRA) method developed by [62]. The long-term average 87 Sr/ 86 Sr value of TRA-measurements of NIST 987 (reference value ...

In most studies, the marine strontium isotope ratio is related to the riverine strontium flux (e.g. Raymo, 1991, François et al., ... For example, miospores typical for middle and higher latitudes disappeared at the end of the Givetian and equatorial and (sub)tropical forms spread in subpolar areas during the Frasnian ...

The region has a marine equatorial climate with high humidity and high temperatures throughout the year. The annual temperatures range from 18 to 33 °C, with a mean of 26 °C. ... Strontium isotope data coupled with Na/Cl and Cl/Sr ratios enable the identification of saline contributions, which significantly modify the natural Sr isotopic ...

Strontium isotopes. The Sr isotope data of the Maokou Formation from the Qianfo section show an obvious small oscillation between 0.70694 and 0.70718 within 0–70 m then increase to 0.70733 at ~74.5 m, and there is a dramatic drop in the value to 0.70693 at ~84 m (Capitanian).

Geol. Soc. Am. Today, vol. 2, 93 – 95. Google Scholar. Fantle, M. S., and DePaolo, D. J., 2006, Sr isotopes and pore fluid chemistry in carbonate sediment of the Ontong Java Plateau: Calcite recrystallization rates and evidence for a rapid rise in seawater Mg over the last 10 million years. Geochim. Cosmochim.

Much attention has been paid to Sr isotopes. Strontium (Sr), the most abundant trace element in rocks, soil, water, and organisms, is an alkaline earth metal with an atomic number of 38. Its geochemical properties are similar to those of Calcium (Ca) which is often replaced in the form of isomorphism (Pathak and Gupta, 2019). Thus, Sr is ...

STRONTIUM ISOTOPES IN PORE WATERS OF EAST EQUATORIAL PACIFIC SEDIMENTS: INDICATORS OF SEAWATER ADVECTION THROUGH OCEANIC CRUST AND SEDIMENTS1 S. Oyun,2 H. Elderfield,2 and G.P. Klinkhammer3 ABSTRACT Pore-water samples from the equatorial sedimentary bulge area show reversals in depth …

Strontium isotope stratigraphy: LOWESS version 3: best fit to the marine Sr-isotope curve for 0-509 Ma and accompanying look-up table for deriving numerical age. ... Pac. Equatorial Transect IODP Prel Rept., 320 (2009), 10.2204/iodp.pr.320.2009. Google Scholar. Pälike et al., 2012.

Strontium isotope stratigraphy is one of the most powerful and widely applied chemostratigraphic tools to determine ages in otherwise ... N. D., 1973. Oxygen isotope and palaeomagnetic stratigraphy of equatorial Pacific core V28-238: oxygen isotope temperatures and ice volumes on a 10 5 Year and 10 6 year scale. Quaternary …