English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

.   Pumice from the “Minoan eruption” on Thera (Cyclades, Greece) was investigated to reveal the differences between the composition of the bulk material, which contains a certain percentage of crystallites, and the pure glass phase. This is important for the identification of vitric tephra layers found in the Eastern Mediterranean region in archaeological context and in deep sea drilling cores. Eruption products, deposited at some distance, have usually lost their crystalline fraction due to gravity separation and consist only of glass shards. Only major element distributions in such layers and in pumiceous glass phases have been published up to now, but these data are not sufficient for a reliable identification of the volcanic source, as several other eruptions are known to have produced chemically very similar layers in this region (Milos, Nisyros, Yali, Kos). Therefore, a technique has been developed to separate the glass phase from the primary pumice to reveal differences in the trace element distributions obtained by instrumental neutron activation analysis (INAA). X-ray diffractometry and microscopical techniques were applied to check the purity of this fraction. The concentrations of the major constituents, in particular Al, Ca, Fe, K, Mg, Mn, Na, Si, and Ti were determined by X-ray fluorescence (XRF) and electron probe microanalysis (EPMA), those of Al, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Ta, Ti, Th, U, Yb and Zr by instrumental neutron activation analysis and partly also by X-ray fluorescence. Subtle differences between the compositions of the glass phase and the bulk material are explained by differentiation during partial crystallization and their applicability to the classification of tephra layers is demonstrated.

Separation and Analysis of Theran Volcanic Glass by INAA, XRF and EPMA