Pressure techniques were used to remove 83 blades from a preformed obsidian core weighing 820 grams, yielding 17.32 meters of acute cutting edge. The blades represented 91 percent of the original weight (2.1 centimeters of acute cutting edge per gram of original material), thus demonstrating the efficiency of the pressure-blade techniques for the production of acute cutting edges.

For the determination of provenience of obsidian artifacts, precise and accurate measurements of composition patterns of the geologic sources are necessary for definitive and cost-effective assignments. Inter-comparison of data from different laboratories is often difficult. Suggestions for maximizing the usefulness of data already in the literature are made, contributions to a useful data bank of source composition patterns are recorded, and provenience determinations of 30 artifacts excavated in Quirigua, Guatemala are presented to exemplify the technique.

Eruption in El Salvador verstärkte spätantike Klimakrise Forschung zur Chronologie mittelamerikanischer Vulkane löst globales Rätsel 23.08.2019/Kiel. Kalte Sommer, geheimnisvolle dunkle Wolken, Missernten, Seuchenum das Jahr 540 erlebt der Mittelmeerraum eine umfassende Krise. Nach heutigem Kenntnisstand waren zwei große Vulkaneruptionen 536 und um 540 die Auslöser. Doch die Identifizierung der Vulkane blieb umstritten. Ein internationales Team unter Beteiligung des GEOMAR Helmholtz-Zentrums für Ozeanforschung Kiel präsentiert jetzt in der Fachzeitschrift Quaternary Science Reviews einen Hauptverdächtigen für den Ausbruch 540: den Ilopango im heutigen El Salvador.

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