MESOZOIC INTRAPLATE GRANITIC MAGMATISM IN THE ALTAI ACCRETIONARY OROGEN, NW CHINA: IMPLICATIONS FOR THE OROGENIC ARCHITECTURE AND CRUSTAL GROWTH

doi:10.2475/01.2014.01

	MESOZOIC INTRAPLATE GRANITIC MAGMATISM IN THE ALTAI ACCRETIONARY OROGEN, NW CHINA: IMPLICATIONS FOR THE OROGENIC ARCHITECTURE AND CRUSTAL GROWTH
	Wang, Tao 1; Jahn, Bor-ming ; Kovach, Victor P.; Tong, Ying ; Wilde, Simon A.; Hong, Da-wei ; Li, Shan ; Salnikova, Ekaterina B.
刊名	AMERICAN JOURNAL OF SCIENCE
	2014
卷号	314 期号:1 页码:1-42
关键词	Mesozoic granite U-Pb zircon dating geochemistry Nd-Hf isotopes Central Asian Orogenic Belt Chinese Altai
ISSN号	0002-9599
DOI	10.2475/01.2014.01
英文摘要	The Central Asian Orogenic Belt (CAOB) is the world's largest Phanerozoic accretionary orogen and is the most important site for juvenile crustal growth in the Phanerozoic. In this work, we employed U-Pb zircon geochronology to identify the early and middle Mesozoic intraplate granitic intrusive events in the Chinese Altai segment of the southern CAOB in order to better understand the crustal architecture of the CAOB. We also used whole-rock geochemical, Sr-Nd isotopic and zircon Hf isotopic data to constrain the generation for these granitic rocks and to evaluate the implications for vertical crustal growth in this region. The Early Mesozoic granitic intrusions were emplaced between 220 and 200 Ma in the central Altai "microcontinental terrane" (also widely referred to as Units 2 and 3). The granites have shoshonitic and high-K calc-alkaline affinities and show the characteristics of differentiated I-type granite. The whole-rock initial Sr-87/Sr-86 ratios (0.7058-0.7128) and epsilon(Nd)(210) values (-0.6 to -4.3), as well as the zircon epsilon(Hf)(t) values (-4.0 to +5.0) and two-stage Hf model ages (0.94-1.52 Ga), suggest that the granitic magmas were produced from a mixed source with both mantle-derived and recycled crustal components. The middle Mesozoic granites were emplaced at similar to 150 Ma in the southern Altai "accretionary terrane" (Units 4 and 5). They show A-type characteristics with the REE tetrad effect and have positive epsilon(Nd)(151) whole-rock values of +1.0 to +5.2 and two-stage Nd model ages (T-DM2) of 0.6 to 1.0 Ga. Zircon Hf data show positive zircon epsilon(Hf)(151) values of +1 to +8 and two-stage Hf model ages of 0.6 to 1.2 Ga. The Nd-Hf isotopic data suggest that the granitic magmas were derived from short-lived juvenile mantle-derived materials. Thus, the isotopic signatures of all the Mesozoic granites from the central (old terrane) and southern (young accretional terrane) Altai suggest that the basement of both terranes has retained its original nature. The data further imply that the Altai orogen has kept its original architecture of Paleozoic horizontal accretion during Mesozoic time, as commonly observed in accretionary orogens where horizontal tectonics are dominant. All the early Mesozoic intrusions in the Altai were emplaced in an intraplate anorogenic setting; hence are distinguished from the contemporaneous syn- or post-orogenic magmatism in the eastern CAOB. We conclude that the early Mesozoic granites in the CAOB were emplaced in a variety of tectonic settings.
学科主题	构造地质学
WOS关键词	ND ISOTOPIC EVIDENCE ; PLASMA-MASS SPECTROMETRY ; TETRAD REE PATTERNS ; ZIRCON U-PB ; CENTRAL-ASIA ; CONTINENTAL GROWTH ; NORTHWEST CHINA ; TECTONIC IMPLICATIONS ; IGNEOUS ROCKS ; TECTONOMAGMATIC AREA
WOS研究方向	Geology
语种	英语
出版者	AMER JOURNAL SCIENCE
WOS记录号	WOS:000333945400003
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40534]
专题	中国地质科学院地质研究所
作者单位	1.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China 2.Chinese Acad Geol Sci, Beijing SHRIMP Ctr, Beijing 100037, Peoples R China 3.Natl Taiwan Univ, Dept Geosci, Taipei 10764, Taiwan 4.Acad Sinica, Inst Earth Sci, Taipei 115, Taiwan 5.Kovach, Victor P.; Salnikova, Ekaterina B.] Russian Acad Sci, Inst Precambrian Geol & Geochronol, St Petersburg 199034, Russia 6.Wilde, Simon A.] Curtin Univ, Dept Appl Geol, Perth, WA 6845, Australia
推荐引用方式 GB/T 7714	Wang, Tao,Jahn, Bor-ming,Kovach, Victor P.,et al. MESOZOIC INTRAPLATE GRANITIC MAGMATISM IN THE ALTAI ACCRETIONARY OROGEN, NW CHINA: IMPLICATIONS FOR THE OROGENIC ARCHITECTURE AND CRUSTAL GROWTH[J]. AMERICAN JOURNAL OF SCIENCE,2014,314(1):1-42.
APA	Wang, Tao.,Jahn, Bor-ming.,Kovach, Victor P..,Tong, Ying.,Wilde, Simon A..,...&Salnikova, Ekaterina B..(2014).MESOZOIC INTRAPLATE GRANITIC MAGMATISM IN THE ALTAI ACCRETIONARY OROGEN, NW CHINA: IMPLICATIONS FOR THE OROGENIC ARCHITECTURE AND CRUSTAL GROWTH.AMERICAN JOURNAL OF SCIENCE,314(1),1-42.
MLA	Wang, Tao,et al."MESOZOIC INTRAPLATE GRANITIC MAGMATISM IN THE ALTAI ACCRETIONARY OROGEN, NW CHINA: IMPLICATIONS FOR THE OROGENIC ARCHITECTURE AND CRUSTAL GROWTH".AMERICAN JOURNAL OF SCIENCE 314.1(2014):1-42.