Lava fingerprinting using paleomagnetism and innovative X-ray fluorescence spectroscopy: A case study from the Coso volcanic field, California

Geochemistry, Geophysics, Geosystems
By: , and 

Links

Abstract

[1] We demonstrate an efficient method of rigorously separating difficult-to-distinguish lavas into eruptive units based on paleomagnetic remanence direction and rapid X-ray fluorescence spectroscopy (XRF) for Rb, Sr, Y, Zr, and Nb of polished paleomagnetic core samples (called PC XRF). Combined use of paleomagnetic remanence and PC XRF for lava fingerprinting allows correlation of individual eruptive units from one locality to another, permitting compilation of composite stratigraphy and paleomagentic measurement of relative vertical axis rotation of fault-bounded blocks. We test this lava fingerprinting method on rocks from the Coso volcanic field, California, against similar fingerprinting using XRF analysis by established methods. Resulting unit definitions and correlations are the same by both XRF techniques when coupled with paleomagnetic data, but at great time and cost savings with PC XRF. PC XRF analysis is possible because (1) matrix and grain size effects are minimal for the element set analyzed, (2) moderately phyric to aphyric polished paleomagnetic cores are already homogenous on spatial scales of 2 cm, and (3) use of element ratios cancels out some analytical uncertainties as well as minimizes effects of concentration variations due to fractional crystallization. Paleomagnetic remanence direction is an indispensable part of fingerprinting because it distinguishes flows of similar chemistry and can also place constraints on the duration of emplacement of each eruptive unit.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Lava fingerprinting using paleomagnetism and innovative X-ray fluorescence spectroscopy: A case study from the Coso volcanic field, California
Series title Geochemistry, Geophysics, Geosystems
DOI 10.1029/2004GC000707
Volume 6
Issue 4
Year Published 2005
Language English
Publisher American Geophysical Union
Description 17 p.
Country United States
State California
Other Geospatial Coso volcanic field
Google Analytic Metrics Metrics page
Additional publication details