Sentences with phrase «of calcite on»

Not exact matches

Unlike typical crystal structures like shells, which incorporate thousands of smaller, geometrically symmetrical crystals attached to each other, each spine on a sea urchin is a single large calcite crystal with its own convoluted shape.

The thin calcite deposits on cave art can be contaminated by new flows of uranium - containing water, dust, or other detritus, making the art seem older than it is, he and his colleagues argued.

This would also explain the unusual lack of typical pond fossils at the site, as well as the near lack of gnaw marks on bones and calcite and barite concretions found on bones excavated from the quarry.

Up to now previous investigations focused on calcite or aragonite saturation state as indicators of calcifiers thresholds, which may completely miss the vulnerability of many calcifiers.

Williams looked at the radioactive elements uranium and thorium trapped in these calcite crystals, using them as a kind of clock based on the rate at which uranium decays into thorium.

This is a scanning electron microscopy image of a calcite crystal generated in the presence of the sea urchin protein rSpSM50 on a silicon wafer showing organized nanotexturing on exposed surfaces.

To find out whether acid rain was indeed the problem, the team focused on one problematic sliding layer in the Jiweishan avalanche: a thin bed of black shale, which contains slippery clay minerals such as talc, in addition to fine organic material and calcite, which helps cement the shale together.

Multiple forms often nucleated in a single experiment — at least one calcite crystal formed on top of an aragonite crystal while vaterite crystals grew nearby.

These spheres called micelles are molecules that roll up like roly - poly bugs based on the chemistry along their bodies — pointing outwards are the parts of their molecules that play well chemically with both the surrounding water and the calcite, while tucked inside are the parts that don't get along with the watery environment.

In this image, researchers observe distortions in the reaction front (the boundary between the blue and red regions) as they form on the surface of the calcite mineral, driven by the high solution acidity where the reaction fronts become unstable.

This vibrant, colorful necklace is strung with beads of jasper, garnet, agate, and calcite on a length of braided cord.

Handcrafted of quartz and calcite, it blooms on a circlet of glittering glass crystal.

The salt that forms on the surface of concrete (efflorescence) is often a combination of calcium sulphate (gypsum), salt (sodium chloride) and calcium carbonate (calcite).

Go on a guided tour to see the stalactites and stalagmites of Fairy Cave and the calcite - rimmed pools of Royal Cave.

Rain falling on this material dissolved some of the calcite skeletal fragments and then precipitated this calcite in between other grains to cement all of the grains together and turn the material into a limestone.

The color yellow persists as paint residue on the excavator heads and is reflected again in the yellow - hued banded calcite, which, though mined by similar machinery through a process of destruction, now rests in perfect equilibrium in the grip of the sculpture — an essential part of the work.

The afternoon sessions on water isotopes in precipitation was quite exciting because of the number of people looking at innovative proxy archives, including cave records of 18O in calcite, or deuterium in leaf waxes, which are extending the coverage (in time and space) of this variable.

The Patagonian Shelf Break lies on the northern edge of a region that some scientists refer to as the «great southern coccolithophore belt» or the «great calcite belt.»

This shows the effect of historically invisible confounding influences on T: dO18 proxy reconstructions, and explicitly refutes your claim, Kau, that, «ONLY a change in temperature or a change in seawater δ18O can alter the δ18O ratio of foraminiferal calcite.

At some times of year, acidification has already reached a critical threshold for organisms living on Alaska's continental shelves.145 Certain algae and animals that form shells (such as clams, oysters, and crab) use carbonate minerals (aragonite and calcite) that dissolve below that threshold.

Past hypotheses arguing calcification was dependent on carbonate ion concentration, or aragonite and calcite saturation levels, were most likely misled by the fact that higher carbonate ion concentrations are a daily «side effect» of photosynthesis.

By ruling out the unsuitable elements on the periodic table and then through modeling of stratospheric chemistry, the team landed on calcite, a constituent of rocks like limestone, marble and chalk, and one of the Earth's crust's most common compounds.

But since corals, be it with an aragonite or a calcite skeleton, both rely on symbiotic algae as their main source of energy they remain vulnerable, since those algae are highly susceptible to both low pH and high temperatures.

The magnitude of sea - level estimates for the past 100 million years rely heavily on foraminiferal calcite oxygen isotopes (δ18O), which are influenced by temperature, evaporation and precipitation, and diagenesis2.