Sentences with phrase «of volcanic deposits»

Not exact matches

The Secret Pass deposit, categorized as an epithermal - type deposit hosted within Tertiary Volcanics (Bullfrog Tuff), currently hosts an inferred resource of 11.1 million tonnes grading 0.93 g / t Au using a 0.3 g / t cut - off, containing an estimated 335,000 oz Au.

The climate in the Auvergne also contributes to their unique texture: a lack of humidity and abundant sunshine, courtesy of the surrounding mountains and volcanic deposits, ensures that the lentils dry on the plant all by themselves.

The maroon patch within the baby - blue area at the center of the crater signifies what has been identified as pyroclastic deposits centering on a volcanic vent.

For example, the researchers found higher - than - average concentrations of water in lunar volcanic deposits near the Moon's equator, where background water in the soil is scarce.

The entire cliff would have been deposited very quickly from a fast - moving current of hot gas and ash (a pyroclastic density current), and the extreme temperatures (900-1000 °C) caused the ash to weld to the ground and effectively enameled the area in dense volcanic glass.

The spatial deposition of sulfur particles in the bipolar ice cores, as calculated in the model, agrees well with the actually measured deposits of large volcanic eruptions, such as Pinatubo in 1991 or even of Tambora of 1815.

But geologists have found little evidence of activity in recent eons; the newest volcanic deposits date back millions of years.

«In any case, the results of our model study give a clear indication that the bipolar variability of sulfate deposits must be taken into consideration if the traces of large volcanic eruptions are to be deduced from ice cores,» says Dr. Krüger, «Several research groups that deal with this issue have already contacted us to verify their data through our model results.»

Biologist Sonja Wedmann, then at the Institute of Paleontology at the University of Bonn, analyzed the fossil after it was dug up from oil shale deposits in what was once a small lake formed by volcanic activity.

ROUGH TERRAIN Underwater robots helped map Havre's 2012 eruption, creating elevation maps of the site and allowing researchers to figure out the volume of volcanic debris deposited there.

Ward and Delph calculated their plutonic - to - volcanic ratio by comparing the volume of regions where seismic waves travel extremely slowly beneath volcanically active regions, indicating some melt is present, with the volume of rock deposited on the surface by volcanoes.

«Ash from dinosaur - era volcanoes linked with shale oil, gas: Shale oil, gas deposits accompany ash layers from thousands of volcanic eruptions.»

The volume of ash deposited, and the estimated height of the eruption plume (43 kilometers above sea level) put the eruption's magnitude at a minimum of 7 on the volcanic explosivity index (which has a scale of 1 to 8)-- making it one of the largest known in the Holocene.

Deposits from past submarine slides also reveal new insights into the development of volcanic islands as they grow under the sea.

A younger volcanic deposit lying in the rock above these fossils includes zircons, tiny bits of silicate mineral that often contain trace amounts of uranium.

After decades of dueling studies about whether it was an asteroid or volcanic eruptions that did in the dinosaurs, it is apparent that the mineral - deposit evidence is indirect and open to interpretation, even if the scientists advancing the various claims sound pretty sure of themselves.

Using radioisotopic dating of underlying volcanic deposits, researchers in 1993 estimated them to be 228 million years old.

The pink areas are new deposits of volcanic ash; the orange plug is older material.

Molten rock (or magma) has a strong influence on our planet and its inhabitants, causing destructive volcanic eruptions and generating some of the giant mineral deposits.

As a result, they have established that the formation of Earth's crust, volcanic super eruptions and mineral deposits occur under very specific yet different conditions.

Those glimpses of the surface revealed deposits of pyroclastic ash — the telltale signs of volcanic explosions — peppering the planet's surface.

Lead author of the study Dr Tom Gernon, Lecturer in Earth Science at the University of Southampton, said: «When volcanic material is deposited in the oceans it undergoes very rapid and profound chemical alteration that impacts the biogeochemistry of the oceans.

The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea.

«In contrast to most volcanic deposits, the melt inclusions are encased in crystals that prevent the escape of water and other volatiles during eruption.

Gray rubble on the flanks of Mauna Kea on the island of Hawaii lie in contrast to the red volcanic rock behind them, and were deposited by a glacier that disappeared thousands of years ago.

At the bulleye's center is a region of what appears to be deposits of volcanic material, a sign that the center of the basin may have been covered by a volcanic flow sometime soon after the SPA impact.

In contrast, the smaller dark spots (which can appear as gray, brown, or red) may be the remains of low - speed, carbon - rich asteroids that splattered such» deposits» onto Vesta's surface, or they may be the result of higher - speed asteroid that melted and darkened volcanic basaltic crust on crater walls and floors, or on surrounding hills and ridges (NASA DAWN news release).

Geologists have long believed that these minerals were formed by volcanic activity, but in a new study, researchers from McGill University in Canada argue that the silica - rich minerals may have been deposited in the crust of a young Earth by «silicate rain.»

When this superheated water rises from underground, it passes and often partially melts old lava flow deposits of rhyolite, a volcanic rock of silica - rich composition.

Bentonite clay is sedimentary clay composed of weathered and aged volcanic ash, the most active deposits of which are in Wyoming and Montana.

100 % Natural Bentonite Clay Redmond Bentonite Clay is the result of volcanic ash deposited in seawater 150 million years ago.

PURE - Redmond Bentonite Clay is the result of volcanic ash deposited in seawater 150 million years ago.

Although no written records exist of the early history of the Phalaborwa district, archaeologists and geologists agree that it was once an area of intense volcanic activity; resulting in rich iron deposits.

The geology of Belize can be divided broadly into the Northern Lowlands, the Maya Mountains, the Toledo Beds and the Pliestocene deposits, but there are other features including volcanic deposits of bentonite in the north and volcanic outcrops along the southern boundary of the Maya Mountains.

The area south - west of the summit has interesting volcanic features with smoking craters, bright yellow sulphur deposits and steep slopes of fine black sand.

They found that the diatom - rich sediments, deposited during the warm intervals, were predominantly composed of material from one terrane - the Jurassic to Cretaceous volcanic rocks and associated sedimentary rocks of the Ferrar Large Igneous Province (FLIP).

Numerous indicators of volcanic activity at the P - T boundary are present, though they are similar to bolide impact indicators, including iridium deposits.

The massive volumes of volcanic debris deposited in the Spirit Lake and the Toutle River system during the 1980 eruption of Mount St. Helens in southwest Washington State drastically changed the region and left its 50,00... More >>

Geologists generally agreed that sea floor volcanic processes were important in the 1960's in formation of Volcanogenic Massive Sulphide deposits and maybe earlier, however it was not until 1977 that observational proof was acquired.

Active black smokers were first observed in 1977, however the geological record from Archean times revealed deposits of massive sulphides that were laid down on or near the sea floor in volcanic conditions.

The images show that the axial valley at 4,000 m water depth is blanketed by an extensive set of pyroclastic deposits, raising important questions regarding the accumulation and discharge of magmatic volatiles on such ridges and demonstrating that large - scale pyroclastic activity is possible along even the deepest portions of the global mid-ocean ridge volcanic system.

The layers are matched to calendar years using the telltale deposits of known volcanic eruptions; and 3) connecting the ages of the ice and the air — i.e., the time difference between snow falling and air bubbles getting enclosed — is a problem all of its own.