Oxygen Isotope Fractionation between Coexisting Calcite and Dolomite.

نویسنده

  • J N Weber
چکیده

The oxygen isotopic composition of calcite from carbonate rocks of the lower unit of the Flagstaff formation (Paleocene) exposed along the western margin of the Wasatch Plateau, Utah, is about 7 per mil lower than that of coexisting dolomite, suggesting that isotopic equilibration of these two minerals can occur at relatively low temperatures. Unlike recent isotopic evidence presented by Degens and Epstein, the data do not preclude a primary chemical origin for the dolomite.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Concentration effect on equilibrium fractionation of Mg-Ca isotopes in carbonate minerals: Insights from first-principles calculations

Naturally occurring carbonates have a wide variation in Mg and Ca contents. Using the density-functional-theory calculations, this study examines the effect of Mg and Ca concentrations on bond lengths and equilibrium fractionation factors of Mg-Ca isotopes among calcite-type carbonate minerals (MgxCa1 xCO3). Mg content x and Ca content (1 x) of the investigated carbonate minerals range from 1/1...

متن کامل

An explanation of the effect of seawater carbonate concentration on foraminiferal oxygen isotopes

Stable oxygen isotope ratios of foraminiferal calcite are widely used in paleoceanography to provide a chronology of temperature changes during ocean history. It was recently demonstrated that the stable oxygen isotope ratios in planktonic foraminifera are affected by changes of the seawater chemistry carbonate system: the dO of the foraminiferal calcite decreases with increasing CO3 22 concent...

متن کامل

Formation of Replacement Dolomite in the Latemar Carbonate Buildup, Dolomites, Northern Italy: Part 1. Field Relations, Mineralogy, and Geochemistry

Replacement dolomite in the Latemar carbonate buildup, northern Italy, formed when limestone was infiltrated by and reacted with Mg-rich fluid. It occurs in discrete bodies in sharp contact with unreacted limestone. The dolomite developed in a nearly orthogonal lattice of vertical columns (replacement of limestone breccia pipes) and sheets (replacement along fractures and limestone-dike contact...

متن کامل

Fluid evolution in CM carbonaceous chondrites tracked through the oxygen isotopic compositions of carbonates

The oxygen isotopic compositions of calcite grains in four CM carbonaceous chondrites have been determined by NanoSIMS, and results reveal that aqueous solutions evolved in a similar manner between parent body regions with different intensities of aqueous alteration. Two types of calcite were identified in Murchison, Mighei, Cold Bokkeveld and LaPaz Icefield 031166 by differences in their petro...

متن کامل

ELECTRON PARAMAGNETIC RESONANCE (EPR) SPECTROSCOPY AND GEOCHEMISTRY IN TIN EXPLORATION AT RENISON, TASMANIA AUSTRALIA

Rock powder of dolomite samples from the Renison mine area of Tasmania, Australia were analyzed by electron paramagnentic resonance spectroscopy (EPR), Atomic Absorption and Mass Spectrometer to identify alteration related to mineralisation. The least-altered dolomite samples, which are not effected by circulation of diagenetic and hydrothermal fluids are characterised by low Mn and Fe and ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Science

دوره 145 3638  شماره 

صفحات  -

تاریخ انتشار 1964