TY - JOUR
T1 - Internal 238U-series systematics of pumice from the November 13, 1985, eruption of Nevado del Ruiz, Colombia
AU - Schaefer, Stephen J.
AU - Sturchio, Neil C.
AU - Murrell, Michael T.
AU - Williams, Stanley
N1 - Funding Information:
Acknowledgments-This work was supportedb y the Geosciences ResearchP qram, Officeo f BasicE nergyS ciencesU, S Dept.o f Energy( NCS, MTM); the NationalS cienceF oundation( grantsE AR-8608977a nd EAR-8721206t o SNW); the GeologicalS ocietyo f America( grantt o SJS); COLCIENCIAS and INGEOMINAS. This work was supportedi n part by the US Dept. of Energy grant DE-FGO7-80ERI O725( INAA at the Univ. of MissouriR esearchR e-actor). We also thank the staff of the ObservatorioV ul~nol6~co de CoIombia-Mani~l~, and especiallyo ur coikeaguMe arta Lucia CalvacheV . Helpful reviewso n the manuscriptw ere providedb y D. M. Pyle and two anonymousr eviewersC. onversationws ith David Lescinskya lso improvedt his manuscript.
PY - 1993/3
Y1 - 1993/3
N2 - High-precision mass spectrometer and alpha scintillation measurements of 238U-series nuclides were obtained for whole-rock pumice and constituent mineral and glass separates to help interpret the timing and nature of magmatic processes that led up to the 1985 eruption of Nevado del Ruiz volcano. Internal isochron diagrams for (226Ra) Ba vs. (230Th) Ba and ( 230Th 232Th) vs. ( 238U 232Th) show that data define linear arrays, indicating an average crystallization age of 6.1 ± 0.5 ka (Ra-Th isochron) and 7 ± 6 ka (Th-U isochron). Stratigraphic, petrographic, geochemical, repose time, and eruption volume data for the Holocene eruptive sequence of Nevado del Ruiz indicate that significant changes occurred in the subvolcanic magma chamber between eruptions R9 (≈8.6 ka) and R8 (≈3.0 ka). This coincides with the average crystallization age derived from the U-series data and may represent the injection of a new batch (or batches) of mantle-derived magma into the subvolcanic magma chamber.
AB - High-precision mass spectrometer and alpha scintillation measurements of 238U-series nuclides were obtained for whole-rock pumice and constituent mineral and glass separates to help interpret the timing and nature of magmatic processes that led up to the 1985 eruption of Nevado del Ruiz volcano. Internal isochron diagrams for (226Ra) Ba vs. (230Th) Ba and ( 230Th 232Th) vs. ( 238U 232Th) show that data define linear arrays, indicating an average crystallization age of 6.1 ± 0.5 ka (Ra-Th isochron) and 7 ± 6 ka (Th-U isochron). Stratigraphic, petrographic, geochemical, repose time, and eruption volume data for the Holocene eruptive sequence of Nevado del Ruiz indicate that significant changes occurred in the subvolcanic magma chamber between eruptions R9 (≈8.6 ka) and R8 (≈3.0 ka). This coincides with the average crystallization age derived from the U-series data and may represent the injection of a new batch (or batches) of mantle-derived magma into the subvolcanic magma chamber.
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U2 - 10.1016/0016-7037(93)90058-5
DO - 10.1016/0016-7037(93)90058-5
M3 - Article
AN - SCOPUS:0027387203
VL - 57
SP - 1215
EP - 1219
JO - Geochmica et Cosmochimica Acta
JF - Geochmica et Cosmochimica Acta
SN - 0016-7037
IS - 6
ER -