Igneous Rock Associations 12. A Geologist’s Look at Archaeological Ceramics and Glass

Abstract

SUMMARYCeramics and glass represent synthetic metamorphic rocks and obsidian, respectively. Consequently, it is not surprising that many archaeologists have collaborated with geologists on projects dealing not only with lithic artifacts, but with ceramic and glass objects as well. This paper presents an overview of these latter two materials from a geological perspective, considering in turn how they are characterized and classified, their ages constrained, provenance and in some instances use determined, and how they were made. SOMMAIRE INTRODUCTIONIn the course of their education, geologists become well versed in the traditional mainstays of their disciplinemineralogy, stratigraphy, petrology, geochemistry, paleontology, geochronology, structural geology, tectonics -along with a smattering of supporting sciences. Among other things, we learn to place time and space in a broader context than most other scientists aside from astronomers. Archaeologists are not much different, although their appreciation of time is on a much more restricted scale -typically centuries and millennia rather than mega-and gigaannum. Moreover, they usually map on a much more detailed scale than field geologists, and the third dimension of

Dynamics of deep-submarine explosive eruptions

“…There has now been significant documentation of vesicular fragmented deposits in the deep-ocean along mid-ocean ridges and elsewhere (Clague et al, 2003a(Clague et al, , 2000(Clague et al, , 2003b(Clague et al, , 2009Eissen et al, 2003;Fiske et al, 2001;Hekinian et al, 2000;Murch et al, 2019;Rotella et al, 2014;Schipper et al, 2010;Sohn et al, 2008), as well as direct observations of explosive submarine eruptions (Chadwick et al, 2008;Deardorff et al, 2011;Embley et al, 2006;Resing et al, 2011). These field observations have been corroborated by extensive numerical and experimental studies into volatile exsolution and fragmentation processes at high hydrostatic pressures (Büttner et al, 2002;Downey and Lentz, 2006;Dürig et al, 2020b;Wohletz et al, 2013;Wohletz, 1986;Zimanowski et al, 2015), showing that explosive eruptions may occur in the deep-ocean. Conceptual models for the evolution of explosive eruptions in the deep-ocean have been developed, however there still lacks a quantitative understanding of the processes that control the mixing and dispersal of pyroclasts from these styles of eruption.…”