Open AccessDistinguishing between primary and secondary emplacement events of blocky volcanic deposits using rock size distributions
Author(s) -
Bulmer M. H.,
Glaze L. S.,
Anderson S.,
Shockey K. M.
Publication year - 2005
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003jb002841
Subject(s) - geology , lava , volcano , volcanic rock , lava dome , petrology , block (permutation group theory) , geochemistry , geomorphology , geometry , mathematics
Rock size characteristics in rock avalanches and blocky lava flows are different and statistical techniques can be used both to distinguish between and to constrain the different emplacement mechanisms of these two processes. At the Chaos Jumbles rock avalanche deposit in California, rock sizes decrease as a function of distance. The rock avalanche mechanism is an example of a secondary process that can only break existing blocks. In contrast, lava flows at Sabancaya, Peru, were emplaced by primary mechanisms capable of creating as well as breaking blocks. These deposits exhibit uniform block sizes as functions of distance and significantly larger blocks overall than Chaos Jumbles. Rock sizes at Inyo domes, also emplaced by a primary process, are significantly smaller in areas with compressional ridges as compared to vent or jumbled areas.