Results 71 to 80 of about 25,598 (206)

Tracing the source of obsidian from prehistoric sites in Bulgaria

Българско е-Списание за Археология, 2017
Portable X-ray fluorescence (pXRF) spectrometry was used to obtain source determinations for 11 obsidian artefacts from five archaeological sites in Bulgaria. The results show that all the archaeological specimens can be linked to obsidian sources in the
Clive Bonsall, Maria Gurova, Nedko Elenski, Georgi Ivanov, Aneta Bakamska, Georgi Ganetsovski, Radka Zlateva-Uzunova, Vladimir Slavchev   +7 more
doaj  

First technological and provenance analysis on obsidian artifacts from Tafí Valley (Tucumán Province, Argentine Republic)

Journal of Lithic Studies, 2018
The aim of this paper is to report the first analyses carried out on obsidian artifacts recovered from two archaeological sites of the Tafí valley (Tucumán, Argentina), dating to the first and second millennium C.E.
Juan Manuel Montegú, Valeria Leticia Franco Salvi, Julián Salazar   +2 more
doaj   +1 more source

Character of the opposition effect and negative polarization [PDF]

Photometric and polarimetric properties at small phase angles were measured for silicates with controlled surface properties in order to distinguish properties that are associated with surface reflection from those that are associated with multiple ...
Pieters, Carle M., Shkuratov, Yu. G., Stankevich, D. G.   +2 more
core   +1 more source

Thermal properties of vesicular rhyolite [PDF]

, 1994
Thermal diffusivity of rhyolite melt and rhyolite foam (70–80% porosity) has been measured using the radial heat transfer method. Cylindrical samples (length 50–55 mm, diameter 22 mm) of rhyolite melt and foam have been derived by heating samples of ...
Bagdassarov, Bagdassarov, Birch, Blake, Brandeis, Carrigan, D. Dingwell, Eichelberger, Eichelberger, Eichelberger, Fink, Fink, Gable, Geotti-Bianchini, Hampton, Heide, Heiken, Hurle, Jaupart, Jeffreys, Lee, Loeb, Manley, Marsh, Murase, N. Bagdassarov, Neuville, Nield, Oldenburg, Parrot, Sheffield, Sparks, Toramaru, Turner, Webb, Webb, Wilson, Worster   +37 more
core   +1 more source

Slab‐Mantle Interaction During Subduction Initiation: Constraints From Trace Element and Sr‐Nd‐Pb Isotope Systematics of Boninite and Other Magmas and Metamorphic Sole in the Oman Ophiolite

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 2, February 2026.
Abstract The Late Cretaceous Oman ophiolite includes a series of volcanic rocks generated during the transition from spreading ridge to protoarc associated with subduction initiation. We analyzed major and trace elements and Sr, Nd, and Pb isotope compositions of lavas and dikes of the protoarc stage, especially boninites. We also analyzed amphibolites
Tsuyoshi Ishikawa, Kazuya Nagaishi, Kyoko Kanayama, Keitaro Kitamura, Shigeyuki Wakaki, Yuki Kusano, Susumu Umino   +6 more
wiley   +1 more source

The potential of obsidian "big data"

UISPP Journal, 2019
Studies of obsidian provenance have been a core component of the archaeological sciences from the mid-1960s onward. With the growing application of portable X-ray Fluorescence Spectrometers (PXRF) in obsidian research, the number of such studies, and the
Mark Golitko
doaj   +1 more source

Measurement of water in rhyolitic glasses; calibration of an infrared spectroscopic technique [PDF]

, 1986
A series of natural rhyolitic obsidians were analyzed for their total water contents by a vacuum extraction technique. The grain size of the crushed samples can significantly affect these analyses.
Epstein, Samuel, Newman, Sally, Stolper, Edward M.   +2 more
core  

The local paleoenvironment of Kalavan‐2 based on small‐vertebrate remains and its implications for human‐environment‐dynamics between 60 and 35 ka in the Armenian Highlands

Journal of Quaternary Science, Volume 41, Issue 1, Page 153-177, January 2026.
ABSTRACT Kalavan‐2, a high‐altitude (∼1640 m a.s.l.) open‐air site in Armenia, preserves stratified Middle Paleolithic occupations with a rich small‐vertebrate record. Luminescence dating has placed site formation between ~60 and 45 ka, but without independent chronological control of the microvertebrate accumulation.
Dominik L. Rogall, Monika V. Knul, Hugues‐Alexandre Blain, Boris Gasparyan, Ariel Malinsky‐Buller   +4 more
wiley   +1 more source

Obsidiana gris porfírica calco-alcalina del volcán Chaitén en sitios arqueológicos al sur del río Santa Cruz, Patagonoa meridional Porphyritic grey calc-alkaline obsidian from Chaitén volcano in archaeological sites south of the Santa Crus river, southermost Patagonia

Magallania, 2012
En el Parque Nacional Monte León y el Campo Volcánico Pali Aike se han recuperado un núcleo y dos lascas de obsidiana gris porfírica riolítica, la cual es químicamente diferente a los tipos más comunes de obsidianas (negra, gris verdosa veteada y verde ...
CHARLES R STERN, SOLEDAD CARACOTCHE, ISABEL CRUZ, JUDITH CHARLIN   +3 more
doaj  

Deformation of foamed rhyolites under internal and external stresses: an experimental investigation [PDF]

, 1993
The style of magma eruption depends strongly on the character of melt degassing and foaming. Depending on the kinetics of these processes the result can be either explosive or effusive volcanism.
Bagdassarov, Nikolai, Dingwell, Donald B.   +1 more
core   +1 more source