Sentences with phrase «volcanic glass shards»

This can become difficult since the ice chronologies can only be checked by finding and definitively identifying tephra (volcanic glass shards) that can be attributed to these key eruptions; sulphate peaks in the ice are not volcano specific.

Based on the existing age model (24), we targeted a search for cryptotephra (subtle horizons of volcanic glass shards not visually apparent or detectable using remote sensing methods) on the depth interval of 20 — 40 m below lake floor (MBLF) in drill sites MAL05 - 1C and MAL05 - 2A in search of the YTT.

Contiguous and continuous 10 - cm samples were treated with 1 mol / L HCl, sieved (> 25 μm) and density separated (1.95 — 2.55 g ⋅ cm − 3) to isolate volcanic glass shards, which were counted under high - power microscopy.

The number of volcanic glass shards (shards / gram of sediment) was counted in 10 - cm (gray bars) then 1 - cm (black bars) depth samples.

Not exact matches

But when Lavigne's team examined shards of volcanic glass from this volcano, they found that they didn't match the chemical composition of the glass found in polar ice cores, whereas the Samalas glass is a much closer match.

Smith quickly identified the pieces as cryptotephra, very old microscopic glass shards that were ejected during a volcanic eruption.

UNLV emeritus geosciences professor Gene Smith (right) and colleagues identified glass shards from 74,000 - year - old volcanic eruption for study in this week's edition of the journal Nature.

«Scientists have discovered a layer of volcanic ash and glass shards in Antarctica, evidence of an old eruption by a still active volcano that researchers believe may be contributing to the thinning of Antarctic glacial ice.