Sager, William W. et al. (2011): IODP Expedition 324; ocean drilling at Shatsky Rise gives clues about oceanic plateau formation

Leg/Site/Hole:
IODP 324
IODP 324 U1346
IODP 324 U1347
IODP 324 U1348
IODP 324 U1349
IODP 324 U1350
Identifier:
2012-014164
georefid

10.2204/iodp.sd.12.03.2011
doi

Creator:
Sager, William W.
Texas A&M University, Department of Oceanography, College Station, TX, United States
author

Sano, Takashi
National Museum of Nature and Science, Japan
author

Geldmacher, Jorg
author

Almeev, R.
author

Ando, A.
author

Carvallo, C.
author

Delacour, A.
author

Evans, H. A.
author

Greene, A. R.
author

Harris, A. C.
author

Herrmann, S.
author

Heydolph, K.
author

Hirano, N.
author

Idrissi, N.
author

Ishikawa, A.
author

Iturrino, G.
author

Kang, M. H.
author

Koppers, A. A. P.
author

Li, S.
author

Littler, K.
author

Mahoney, J. J.
author

Matsubara, N.
author

Miyoshi, M.
author

Murphy, D. T.
author

Natland, J. H.
author

Ooga, M.
author

Prytulak, J.
author

Shimizu, K.
author

Tominaga, M.
author

Ucho, Y.
author

Widdowson, M.
author

Woodard, S. C.
author

Identification:
IODP Expedition 324; ocean drilling at Shatsky Rise gives clues about oceanic plateau formation
2011
Scientific Drilling
Integrated Ocean Drilling Program Management International, Sapporo; Washington, DC, International
12
24-31
Integrated Ocean Drilling Program (IODP) Expedition 324 cored Shatsky Rise at five sites (U1346-U1350) to study processes of oceanic plateau formation and evolution. Site penetrations ranged from 191.8 m to 324.1 m with coring of 52.6 m to 172.7 m into igneous basement at four of the sites. Average recovery in basement was 38.7%-67.4%. Cored igneous sections consist mainly of variably evolved tholeiitic basalts emplaced as pillows or massive flows. Massive flows are thickest and make up the largest percentage of section on the largest and oldest volcano, late Jurassic age Tamu Massif; thus, it may have formed at high effusion rates. Such massive flows are characteristic of flood basalts, and similar flows were cored at Ontong Java Plateau. Indeed, the similarity of igneous sections at Site U1347 with that cored on Ontong Java Plateau implies similar volcanic styles for these two plateaus. On younger, smaller Shatsky Rise volcanoes, pillow flows are common and massive flows thinner and fewer, which might mean volcanism waned with time. Cored sediments from summit sites contain fossils and structures implying shallow water depths or emergence at the time of eruption and normal subsidence since. Summit sites also show pervasive alteration that could be due to high fluid fluxes. A thick section of volcaniclastics cored on Tamu Massif suggests that shallow, explosive submarine volcanism played a significant role in the geologic development of the plateau summit. Expedition 324 results imply that Shatsky Rise began with massive eruptions forming a huge volcano and that subsequent eruptions waned in intensity, forming volcanoes that are large, but which did not erupt with unusually high effusion rates. Similarities of cored sections on Tamu Massif with those of Ontong Java Plateau indicate that these oceanic plateaus formed in similar fashion.
English
Coverage:Geographic coordinates:
North:38.0100
West:158.2700East: 162.3900
South:32.3000

Igneous and metamorphic petrology; alteration; basalts; boreholes; Cenozoic; cores; Cretaceous; Expedition 324; genesis; igneous rocks; Integrated Ocean Drilling Program; IODP Site U1346; IODP Site U1347; IODP Site U1348; IODP Site U1349; IODP Site U1350; large igneous provinces; lava; Mesozoic; North Pacific; Northwest Pacific; Pacific Ocean; pillow lava; plateaus; sedimentary rocks; sediments; Shatsky Rise; volcanic rocks; volcanism; West Pacific;

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