Results 171 to 180 of about 806 (206)

Discovery of Eocene adakites in Primor’e

Doklady Earth Sciences, 2011
This paper presents the first results of petrochemical and geochemical studies (by the ICP-MS technique) of adakites comprising a small extrusive body in the Ilistaya River basin (West Primor’e). Based on the data of radioisotopic dating (K-Ar method), the age of adakites corresponds to the Middle Eocene (45.52 ± 1.1 Ma).
A. A. Chashchin, V. P. Nechaev, E. V. Nechaeva, M. G. Blokhin   +3 more
openaire   +1 more source

Semi-adakitic magmatism of the Satkatbong diorite, South Korea: Geochemical implications for post-adakitic magmatism in southeastern Eurasia

Lithos, 2018
Abstract The Satkatbong diorite (190 Ma) and the older Yeongdeok granite (250 Ma) in the Yeongnam massif, which is part of the southeastern margin of the Eurasian plate, are affected by a subduction system that is associated with the Izanagi and Farallon plates.
Hoseong Lim, Hyeon Dong Woo, Bora Myeong, Jongkyu Park, Yun-Deuk Jang   +4 more
openaire   +1 more source

Origin of adakite-like plutons in southern Korea

Lithos, 2016
Abstract We present Sr–Nd–Pb isotopic compositions for two adakite-like intrusions in southern Korea (Jindong and Bongnae), including major and trace element concentrations, and the sensitive high-resolution ion microprobe (SHRIMP) zircon U–Pb age. Our aim is to constrain the origin and tectonomagmatic processes that gave rise to the plutons.
Jeong-Im Oh, Sung Hi Choi, Keewook Yi
openaire   +1 more source

Underplating-related adakites in Xinjiang Tianshan, China

Lithos, 2008
Abstract Intermediate to acidic porphyries and dacites in the Awulale and Sanchakou area of the Xinjiang Tianshan region, China, conform to the definition of high-SiO2 adakite (HSA). These volcanic or subvolcanic rocks are characterized by high Na2O (Na2O > K2O), high Sr/Y (51–327), and strong depletions in HREE and HFSE (Nb, Ta, and Ti).
Z.H. Zhao, X.L. Xiong, Q. Wang, D.A. Wyman, Z.W Bao, Z.H. Bai, Y.L. Qiao   +6 more
openaire   +1 more source

Adakite-like and Normal Arc Magmas

2013
New age and whole-rock ⁸⁷Sr/⁸⁶Sr and ¹⁴³Nd/¹⁴⁴Nd isotopic data are used to assess petrogenetic and regional geodynamic processes associated with Late Cretaceous subvolcanic intrusions within the sparsely studied Timok Magmatic Complex (TMC) and Ridanj-Krepoljin Zone (RKZ) of eastern Serbia.
Kolb, Melanie, von Quadt, Albrecht, Peytcheva, Irena, Heinrich, Christoph A., Fowler, Sarah J., Cvetković, Vladica   +5 more
openaire   +1 more source

Association of adakites with gold and copper mineralization in the Philippines

Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science, 1998
Adakites are intermediate or acidic volcanic and plutonic rocks which derive from partial melting of subducted oceanic crust when the subducting slab is young (< 20 Ma) and hot, and at the start and the end of subduction. In the Philippines, most of porphyry Cu and epithermal Au deposits are either spatially and temporally related or cogenetic with ...
Fernando G. Sajona, René C. Maury
openaire   +1 more source

Miocene adakitic intrusions in the Zhongba terrane: Implications for the origin and geochemical variations of post-collisional adakitic rocks in southern Tibet

Gondwana Research, 2017
Abstract Post-collisional adakitic rocks (26–9 Ma) have been recognized in southern Tibet for almost 20 years; however, their origins and geodynamics remain highly controversial. This paper reports geochronological and geochemical data for the Lasa intrusion exposed in the Zhongba terrane and proposes implications for the origins of the Miocene ...
Yalin Li, Xiaohan Li, Chengshan Wang, Yushuai Wei, Xi Chen, Juan He, Ming Xu, Yunling Hou   +7 more
openaire   +1 more source

Crustal thickness and adakite occurrence in the Philippines: Is there a relationship?

Island Arc, 2008
AbstractAdakites are increasingly being recognized worldwide in a variety of tectonic settings. Models on the formation of this geochemically distinct class of volcanic rocks have evolved from partial melting of subducted young, hot oceanic slabs to magmatism resulting from oblique subduction, low‐angle or flat subduction, or even slab‐tearing.
Carla B. Dimalanta, Graciano P. Yumul, Jr   +1 more
openaire   +1 more source

TTGs and adakites: are they both slab melts?

Lithos, 2005
Abstract Although both high-Al TTG (tonalite–trondhjemite–granodiorite) and adakite show strongly fractionated REE and incompatible element patterns, TTGs have lower Sr, Mg, Ni, Cr, and Nb/Ta than most adakites. These compositional differences cannot be easily related by shallow fractional crystallization. While adakites are probably slab melts, TTGs
openaire   +1 more source

Adakites from Solander Island, New Zealand

New Zealand Journal of Geology and Geophysics, 1997
Abstract The subduction related, island arc Pleistocene volcano of Solander Island in Foveaux Strait is composed of adakite, a new rock type first described from Adak Island in the Aleutian arc. Adakites are formed by the partial fusion of young oceanic crust under eclogitic facies conditions.
A. Reay, D. Parkinson
openaire   +1 more source