| Item type |
デフォルトアイテムタイプ（フル）(1) |
| 公開日 |
2008-03-27 |
| タイトル |
|
|
タイトル |
Petrology and petrogenesis of volcanic rocks from the Uegusukudake Formation in Kume-jima, central Ryukyu Arc |
|
言語 |
en |
| 作成者 |
Kitagawa, Hiroshi
Shinjo, Ryuichi
Kato, Yuzo
新城, 竜一
|
| アクセス権 |
|
|
アクセス権 |
open access |
|
アクセス権URI |
http://purl.org/coar/access_right/c_abf2 |
| 内容記述 |
|
|
内容記述タイプ |
Other |
|
内容記述 |
Major and trace element concentrations and Sr and Nd isotopic ratios are presented for volcanic rocks from the Uegusukudake Formation (～$3-2 Ma) in Kume-jima, central Ryukyu Arc, in order to understand the origin of varieties of erupted magmas. The Uegusukudake Formation is mainly composed of lavas and pyroclastic rocks with subordinate dikes. Volcanic rocks collected from lavas and dikes are grouped into four types based on their petrological characteristics: (1) picrite basalt (PB); (2) aphyric, tholeiitic basalt and basaltic andesite (A-TH); (3) porphyritic, tholeiitic basaltic andesite (P-TH); and (4) porphyritic, calc-alkaline basaltic andesite and andesite (CA), in ascending order. The PB sample is isotopically distinct in having significantly low ^<87>Sr/^<86>Sr (0.7035) and high ^<143>Nd/^<144>Nd (0.51290) compared with the other three types. The A-TH, P-TH, and CA types have similar isotopic compositions (^<87>Sr/^<86>Sr=0.7045-0.7054, ^<143>Nd/^<144>Nd=0.51270-0.51284) and show rather coherent incompatible trace element patterns. These results suggest that the three types of magmas were derived from a similar source material, distinctive from the source of the PB magma. A slight difference in isotopic and trace element ratios (La/Sm and La/Yb) among the three types can be attributed to the different degree of contributions of crustal assimilation. Geochemical variations within the A-TH type rocks can be explained by fractional crystallization, and the variation of the CA type is considered to have resulted from internal hybridization within a single magma reservoir. For the variation of the P-TH type, plagioclase accumulation is inferred to have played a dominant role. |
| 内容記述 |
|
|
内容記述タイプ |
Other |
|
内容記述 |
紀要論文 |
| 出版者 |
|
|
出版者 |
琉球大学理学部 |
|
言語 |
ja |
| 言語 |
|
|
言語 |
eng |
| 資源タイプ |
|
|
資源タイプ識別子 |
http://purl.org/coar/resource_type/c_6501 |
|
資源タイプ |
departmental bulletin paper |
| 出版タイプ |
|
|
出版タイプ |
VoR |
|
出版タイプResource |
http://purl.org/coar/version/c_970fb48d4fbd8a85 |
| 識別子 |
|
|
識別子 |
http://hdl.handle.net/20.500.12000/5383 |
|
識別子タイプ |
HDL |
| 収録物識別子 |
|
|
収録物識別子タイプ |
ISSN |
|
収録物識別子 |
0286-9640 |
| 収録物識別子 |
|
|
収録物識別子タイプ |
NCID |
|
収録物識別子 |
AN00250774 |
| 収録物名 |
|
|
収録物名 |
琉球大学理学部紀要 |
|
言語 |
ja |
| 収録物名 |
|
|
収録物名 |
Bulletin of the College of Science. University of the Ryukyus |
|
言語 |
en |
| 書誌情報 |
号 77,
p. 81-103,
発行日 2004-03
|
No77p81.pdf
