|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| Geological Magazine |  |
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry and South China Sea Institute of Oceanology, Chinese Academy of Sciences, Wushan, Guangzhou, 510640, China
* Author for correspondence: guofengt{at}263.net
Both low-Al and high-Al adakitic andesites erupted at ~ 114 Ma in the Sulu collisional belt, eastern China, provide evidence for recycling of continental crust into the mantle more than 100 million years after the Triassic (~ 240 Ma) collision between the North China and Yangtze blocks. These rocks display similar normalized trace element patterns, with enrichments in large ion lithophile elements (LILE), light rare earth elements (LREE) and depletions in Nb, Ta and Ti, and have highly radiogenic Sr and non-radiogenic Nd isotopic compositions (high-Al: 87Sr/86Sr(i) = 0.70645–0.70715 and 
Nd(t) = –20.1 to –19.1; low-Al: 87Sr/86Sr(i) = 0.70593–0.70598 and Nd(t) = –17.1 to –15.8). The high-Al (Al2O3 > 15 %) adakitic andesites are compositionally comparable with experimental slab melts, whereas the low-Al series (Al2O3 ~ 13 %) have higher MgO, Cr and Ni, and higher Sr/Y ratios, and are compositionally comparable with slab melts hybridized by mantle peridotites. Combined major- and trace-element and Sr–Nd isotope data indicate that the two types of adakitic andesites have been derived from a LILE- and LREE-enriched eclogitic lower continental crust; in the case of the high-Al adakitic andesites, the melts underwent insignificant mantle contamination, whereas the low-Al magmas reacted with peridotites. Generation of the two types of late Mesozoic adakitic andesites favours a model of lithospheric delamination, leading to asthenospheric upwelling and extensive melting of lower continental crust, including a delaminated block, in the Sulu belt.
Key Words: geochemistry • lower continental crust • adakites • Late Mesozoic • Sulu belt
This article has been cited by other articles:
|
|
 |
|
  H.-Y. TANG, J.-P. ZHENG, and C.-M. YU Age and composition of the Rushan intrusive complex in the northern Sulu orogen, eastern China: petrogenesis and lithospheric mantle evolution Geological Magazine, March 1, 2009; 146(2): 199 - 215. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Tirel, P. Gautier, D. J. J. van Hinsbergen, and M. J. R. Wortel Sequential development of interfering metamorphic core complexes: numerical experiments and comparison with the Cyclades, Greece Geological Society, London, Special Publications, January 1, 2009; 311(1): 257 - 292. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. ACQUAFREDDA, A. FORNELLI, G. PICCARRETA, and A. PASCAZIO Multi-stage dehydration-decompression in the metagabbros from the lower crustal rocks of the Serre (southern Calabria, Italy) Geological Magazine, May 1, 2008; 145(3): 397 - 411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M.-L. HOU, Y.-H. JIANG, S.-Y. JIANG, H.-F. LING, and K.-D. ZHAO Contrasting origins of late Mesozoic adakitic granitoids from the northwestern Jiaodong Peninsula, east China: implications for crustal thickening to delamination Geological Magazine, July 1, 2007; 144(4): 619 - 631. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Guo, E. Nakamuru, W. Fan, K. Kobayoshi, and C. Li Generation of Palaeocene Adakitic Andesites by Magma Mixing; Yanji Area, NE China J. Petrology, April 1, 2007; 48(4): 661 - 692. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Corfu, R. J. Roberts, T. H. Torsvik, L. D. Ashwal, and D. M. Ramsay Peri-Gondwanan elements in the Caledonian Nappes of Finnmark, Northern Norway: Implications for the paleogeographic framework of the Scandinavian Caledonides Am J Sci, February 1, 2007; 307(2): 434 - 458. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
