Guidelines for Accurate and Precise Stable Isotope Analysis of Calcite, Dolomite, and Magnesite Using a Carbonate Device for Continuous Flow-Isotope Ratio Mass Spectrometry (CF-IRMS).

Rationale: Carbonate minerals are one of the most popular samples for an automated sample preparation system for CF-IRMS, such as GasBench II and iso FLOW, but no standardized analytical protocols exist. This study gives guidelines on optimal analytic conditions for carbon and oxygen isotope analysis of Ca-Mg carbonates when using the carbonate-phosphoric acid reaction method.

Methods: Calcite (CaCO-McMaster Carrara), dolomite (CaMg(CO)-MRSI Dolomite), and magnesite (MgCO-ROM Brazil Magnesite) with two grain size fractions (< 74 and 149-250 μm) were reacted with 103% (specific gravity of 1.

Enzymatically catalyzed CO -H O equilibration for oxygen isotope analyses of aqueous samples.

Rationale: The classic CO -H O equilibration method is a very popular technique for the measurement of the oxygen isotope composition of aqueous samples in stable isotope geochemistry. This study examined whether enzymatically controlled CO -H O equilibration by carbonic anhydrase (CA) could reduce the time for oxygen isotope equilibrium between CO and H O at 25°C.

Methods: Four types of aqueous samples containing CA were equilibrated with CO gases using a continuous flow isotope ratio mass spectrometer equipped with an automated gas sample collection device.

A new online technique for the simultaneous measurement of the δ13C value of dissolved inorganic carbon and the δ18O value of water from a single solution sample using continuous-flow isotope ratio mass spectrometry.

Rationale: The oxygen isotope study of water reservoirs (δ(18)OH2O values) and the carbon isotope study of dissolved inorganic carbon (δ(13)CDIC values) are powerful tools to decipher Earth's past and present environmental changes. This study presents a novel online analytical technique, namely the DIC evolved CO2 Gas Equilibration Method (DIC-CO2-GEM), in which the δ(18)OH2O and δ(13)CDIC values can be simultaneously determined from a single solution sample.

Methods: The DIC-CO2-GEM measures both δ(18)OH2O and δ(13)CDIC values concurrently by combining the fundamental principles of the classic CO2-H2O equilibration and gas evolution methods, respectively.

Isotopic evidence for age-related immigration to imperial Rome.

Oxygen stable isotope ratios (delta(18)O) have been determined in carbonate in paired first and third molar teeth from individuals (N = 61) who lived in the town of Portus Romae ("Portus") and who were buried in the necropolis of Isola Sacra (First to Third centuries AD) near Rome, Italy. We compare these analyses with data for deciduous teeth of modern Roman children. Approximately one-third of the archaeological sample has first molar (M1) values outside the modern range, implying a large rate of population turnover at that time, consistent with historical data.

A preliminary analysis of the DNA and diet of the extinct Beothuk: a systematic approach to ancient human DNA.

We have used a systematic protocol for extracting, quantitating, sexing and validating ancient human mitochondrial and nuclear DNA of one male and one female Beothuk, a Native American population from Newfoundland, which became extinct approximately 180 years ago. They carried mtDNA haplotypes, which fall within haplogroups X and C, consistent with Northeastern Native populations today. In addition we have sexed the male using a novel-sexing assay and confirmed the authenticity of his Y chromosome with the presence of the Native American specific Y-QM3 single nucleotide polymorphism (SNP).