Petrology and geochronology of basalt breccia from the 1996 earthquake swarm of Loihi seamount, Hawaii: magmatic history of its 1996 eruption

被引:70
作者
Garcia, MO [1 ]
Rubin, KH
Norman, MD
Rhodes, JM
Graham, DW
Muenow, DW
Spencer, K
机构
[1] Univ Hawaii, Hawaii Ctr Volcanol, Dept Geol & Geophys, Honolulu, HI 96822 USA
[2] Macquarie Univ, Sch Earth Sci, Key Ctr Geochem Evolut & Metallogeny Continents, N Ryde, NSW 2109, Australia
[3] Univ Massachusetts, Dept Geosci, Amherst, MA 01003 USA
[4] Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA
[5] Univ Hawaii, Dept Chem, Honolulu, HI 96822 USA
基金
澳大利亚研究理事会; 美国国家科学基金会;
关键词
Hawaii; Loihi; magmatic processes; submarine volcanism; petrology; geochronology; lava geochemistry;
D O I
10.1007/s004450050211
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Samples of basalt were collected during the Rapid Response cruise to Loihi seamount from a breccia that was probably created by the July to August 1996 Loihi earthquake swarm, the largest swarm ever recorded from a Hawaiian volcano. Po-210-Pb-210 dating of two fresh lava blocks from this breccia indicates that they were erupted during the first half of 1996, making this the first documented historical eruption of Loihi. Sonobuoys deployed during the August 1996 cruise recorded popping noises north of the breccia site, indicating that the eruption may have been continuing during the swarm. All of the breccia lava fragments are tholeiitic, like the vast majority of Loihi's most recent lavas. Reverse zoning at the rim of clinopyroxene phenocrysts, and the presence of two chemically distinct olivine phenocryst populations, indicate that the magma for the lavas was mixed just prior to eruption. The trace element geochemistry of these lavas indicates there has been a reversal in Loihi's temporal geochemical trend. Although the new Loihi lavas are similar isotopically and geochemically to recent Kilauea lavas and the mantle conduits for these two volcanoes appear to converge at depth, distinct trace element ratios for their recent lavas preclude common parental magmas for these two active volcanoes. The mineralogy of Loihi's recent tholeiitic lavas signify that they crystallized at moderate depths (similar to 8-9 km) within the volcano, which is approximately 1 km below the hypocenters for earthquakes from the 1996 swarm. Taken together, the petrological and seismic evidence indicates that Loihi's current magma chamber is considerably deeper than the shallow magma chamber (similar to 3-4 km) in the adjoining active shield volcanoes.
引用
收藏
页码:577 / 592
页数:16
相关论文
共 60 条
[1]  
[Anonymous], GEOCHEMICAL SOC SPEC
[2]  
[Anonymous], GEOL SOC LOND SPEC P, V42, P313
[3]  
[Anonymous], 1968, GEOL SOC AM MEM, V116, P477, DOI [10.1130/MEM116-p477, 10.1130/MEM116, DOI 10.1130/MEM116]
[4]   THE URANIUM AND THORIUM DECAY SERIES NUCLIDES IN MT ST-HELENS EFFUSIVES [J].
BENNETT, JT ;
KRISHNASWAMI, S ;
TUREKIAN, KK ;
MELSON, WG ;
HOPSON, CA .
EARTH AND PLANETARY SCIENCE LETTERS, 1982, 60 (01) :61-69
[5]   Ocean-bottom seismometer observations of seismic activity at Loihi Seamount, Hawaii [J].
Bryan, C ;
Cooper, P .
MARINE GEOPHYSICAL RESEARCHES, 1995, 17 (06) :485-501
[6]   VOLATILES IN PILLOW RIM GLASSES FROM LOIHI AND KILAUEA VOLCANOS, HAWAII [J].
BYERS, CD ;
GARCIA, MO ;
MUENOW, DW .
GEOCHIMICA ET COSMOCHIMICA ACTA, 1985, 49 (09) :1887-1896
[7]  
CAPLANAUERBACH J, 1997, GEOL SOC AM ABSTR, V29, P7
[8]   PETROLOGY OF ULTRAMAFIC XENOLITHS FROM LOIHI SEAMOUNT, HAWAII [J].
CLAGUE, DA .
JOURNAL OF PETROLOGY, 1988, 29 (06) :1161-1186
[9]  
Decker RW., 1983, EOS, V64, P545, DOI [DOI 10.1029/EO064I037P00545-01, 10.1029/EO064i037p00545-01]
[10]  
Dowty E., 1980, CRYSTAL GROWTH NUCLE, DOI DOI 10.1515/9781400854493.419