Sentences with phrase «find isotopic»

We did not find isotopic evidence that a global ice sheet impacted overall marine productivity.

But we found the isotopic composition of the deep water was similar to that of modern rainfall, which means the system in the Sydney Basin has been relatively stable for thousands of years.

Now, locked in limestone that was formed in shallow seawater offshore of the supercontinent Pangaea, scientists have found an isotopic signal to support a sharp drop in pH. The catastrophe holds a cautionary lesson: Due to the burning of fossil fuels, today's oceans are acidifying at an even faster rate than they were at the time of the extinctions, although it hasn't yet persisted nearly as long.

Using innovative isotopic analysis techniques and mathematical modeling, he has shown that Mars is a planetary embryo, found isotopic similarities between the Moon, Earth and meteorites, and proposed a new narrative for the origin of Earth's unique iron composition.

Not exact matches

They found that the isotopic signatures of sulfur (in sulfate), carbon (in dissolved inorganic carbon) and strontium from water samples collected from tributaries adjacent to mountaintop mining sites are distinguishable from those collected from unaffected upstream waters.

«Essentially, we found that these elements have unique isotopic fingerprints, meaning we can use them as diagnostic tools to quantify mountaintop mining's relative contribution to contamination in a watershed,» said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.

Dust found in the ice gives a record of what was in the air thousands of years ago, whether from volcanic eruptions or human activity, and the isotopic composition of the hydrogen and oxygen molecules in the snow give a record of the temperature of the earth at the time.

They found a sharp dip in methane concentrations after 1992; that dip corresponded with a decrease in a source with a carbon isotopic value of about -40 ‰.

The discovery's telltale sign is found in the ratio of an isotopic form of hydrogen, called deuterium, to standard hydrogen.

Animals that live in the sea have ratios of carbon and nitrogen isotopes that differ from those found in terrestrial animals, and this isotopic signature is passed on to the people who eat them.

The researchers analysed quartz crystals from Toba, and found a distinct shift in the isotopic composition towards the outer rim of the crystals.

We would think that if an ice sheet covered the oceans it would have had an impact on marine production or photosynthesis and we find no carbon isotopic evidence for this.

Rather than excavate, the team intends to use the Swedish Research Council's largest ever archaeo logical grant to reexamine spectacular existing finds using modern methods such as isotopic analysis.

Nonetheless, the findings are valuable because isotopic nitrous oxide data from the Arctic and sub-Arctic are extremely rare.

The team found that the isotopic signature of bones located at the site changed over time.

This is what the team found in one of the lunar samples that was abundant enough for isotopic analysis.

Isotope geochemist Mukul Sharma of Dartmouth College in Hanover, New Hampshire, says he has been unable to find any significant amount of platinum - group elements with the distinctive isotopic signature showing that they came from space.

The tracers, which have been tested both in the laboratory and the field, are based on the distinctive isotopic and geochemical signatures of two elements, boron and strontium, found in coal ash effluent.

The influx of nomadic populations into east - central Europe in the fifth century AD may have caused enormous political upheaval and documented episodes of violence, but isotopic evidence shows people finding strategies to mitigate and perhaps even to benefit from these changes by modifying their subsistence economies.»

The team was also surprised to find that reconstructions of the environment around Lomekwi at 3.3 million years ago, from the associated animal fossils and isotopic analyses of the site's soil, indicate the area was much more wooded than paleoenvironments associated with later East African artifact sites from after 2.6 million years.

This talk provides an overview and tour of the findings from Curiosity, featuring spectacular high definition images, tantalizing mineralogical evidence for fresh water, and atmospheric isotopic measurements indicative of an ancient climate different from today.

Using a laser technique which removes negligibly small amounts of dental enamel, and analyzing trace amounts of isotopic Strontium, they found individuals with small teeth roamed more widely from their birthplace than did individuals with large teeth.

Mortimer et al. (2017b) discuss new Ar / Ar and limited U — Pb ages and geochemistry (both trace element and Nd isotopic analyses) of widespread volcanism on the northern part of the Zealandia continent by using dredged samples obtained in different cruises and integrated with their earlier findings on the southern Zealandia in an attempt to give a more updated picture of magmatism across the whole Zealandia continent.

The UniChem connectivity search function allows users to find not only exact matches of their chemical structure across 60 million related molecules from 21 data sources worldwide, but also identifies «equivalent» structures that have the same atom connectivity while differing in stereochemistry or isotopic composition, or which exist in a different salt form.

u A. J. T. Jull et al., «Isotopic Evidence for a Terrestrial Source of Organic Compounds Found in Martian Meteorites Allan Hills 84001 and Elephant Moraine 79001,» Science, Vol.

[Response: My recollection is that Zachos had the same observation from ODP cores, that surface - dwelling forams were either isotopically heavy or light, never transitional, but bottom - dwellers could be found with transitional isotopic composition.

We determined the chemical and isotopic compositions of the liquid CO2 found on Yonaguni IV knoll hydrothermal site, as well as those in hydrothermal fluid venting from the surrounding chimneys.

(Partisan) description: The authors studied the isotopic composition of carbon (δ13C) and hydrogen (δD) in organic matter found in two sediment cores retrieved from Lake Korttajarvi.

We can determine this from isotopic analysis of the CO2 molecules found in the air which identifies those molecules resulting from combustion of fossil fuel.

High methane concentrations in well - ice - bonded sediments and gas releases suggest that pore - space hydrate may be found at depths as shallow as 119 m. Geochemical and isotopic determinations suggest that the methane hydrate observed in the core hole is biogenic (microbial) in origin.

These findings are based on the isotopic composition of plant leaf waxes in marine sediments.