Tracing provenance and sediment fluxes in the Irrawaddy River basin (Myanmar)

doi:10.1016/j.chemgeo.2016.06.010

CORC > 地质与地球物理研究所 > 中国科学院地质与地球物理研究所 > 岩石圈演化国家重点实验室

	Tracing provenance and sediment fluxes in the Irrawaddy River basin (Myanmar)
	Garzanti, Eduardo 1; Wang, Jiang-Gang 2; Vezzoli, Giovanni 1; Limonta, Mara 1
刊名	CHEMICAL GEOLOGY
	2016-11-15
卷号	440 页码:73-90
关键词	Sand petrology Heavy minerals Bulk-sediment geochemistry Detrital zircon U-Pb geochronology Stream-profile analysis Tectonic geomorphology
DOI	10.1016/j.chemgeo.2016.06.010
文献子类	Article
英文摘要	This study illustrates the petrographic, heavy-mineral, geochemical and geochronological signatures of sand transported by various branches of the Irrawaddy (Ayeyarwadi) River, one of the first in the world for sediment flux. Intrasample and intersample compositional variability, weathering and hydraulic-sorting controls are also discussed. Feldspatho-quartzose sand in Irrawaddy headwaters is largely derived first-cycle from mid-crustal metamorphic and plutonic rocks of the Mogok Belt and Lohit complex, whereas feldspatho-litho-quartzose Chindwin sand is largely recycled from supracrustal, sedimentary and very low-grade metasedimentary units. Additional mafic to ultramafic detritus is derived from ophiolites and blueschists exposed from the Indo-Burman Ranges to the Jade Mines and Myitkyina belts, linked northward to the Yarlung-Tsangpo suture of the Himalaya. Volcanic detritus derived from the Popa-Wuntho arc or recycled from forearc-basin strata also occurs. Decreasing concentration of most chemical elements along the Irrawaddy reflects progressive addition of detritus, recycled from sedimentary rocks, most evident downstream of the Chindwin confluence. REE patterns with LREE enrichment and negative Eu anomaly reflect the occurrence of allanite, largely derived from granitoid rocks in the Mali catchment. Chemical indices indicate moderate weathering in the monsoon-dominated climate of Myanmar. Young U-Pb ages (15-170 Ma) represent 85% of detrital zircons in Irrawaddy headwater branches, reflecting long-lasting subduction-related magmatism along a ring of fire connecting with the southern and central Lhasa batholiths in Tibet and polyphase metamorphism in the Mogok belt. Chindwin sand contains larger amounts of finer-grained, recycled pre-Mesozoic zircons, also yielding early Mesoproterozoic to Archean ages. Such different petrographic, heavy-mineral, geochemical and geochronological fingerprints characterizing sand in different river branches allowed us to calculate bulk-sediment and zircon-provenance budgets that converge to indicate equivalent sand supply from the Nmai and Mali Rivers to the upper Irrawaddy, and from the Chindwin and upper Irrawaddy to the lower Irrawaddy. This implies that despite of higher erosion potential indicated by stream-profile analysis in high-relief Irrawaddy headwaters, sediment yields and erosion rates are detectably higher in the Chindwin catchment, which is mainly ascribed to higher erodibility of widely exposed siliciclastic rocks. Quantifying sediment provenance and defining erosion patterns based on an integrated compositional database in a big-river system such as the mighty Irrawaddy allows us to expand our understanding of sediment generation processes with the ultimate goal to increase our capacity to read into the stratigraphic record. (C) 2016 Elsevier B.V. All rights reserved.
WOS关键词	MOGOK METAMORPHIC BELT ; GRAIN-SIZE DEPENDENCE ; INDO-BURMAN RANGES ; HF ISOTOPES ; U-PB ; FLUVIAL SEDIMENTS ; DETRITAL MINERALS ; EROSION PATTERNS ; CHEMICAL INDEXES ; MOUNTAIN-RANGES
WOS研究方向	Geochemistry & Geophysics
语种	英语
WOS记录号	WOS:000383937500007
资助机构	Chinese Academy of Sciences(XDB03010100) ; Chinese Academy of Sciences(XDB03010100) ; Chinese Academy of Sciences(XDB03010100) ; Chinese Academy of Sciences(XDB03010100)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/53343]
专题	地质与地球物理研究所_岩石圈演化国家重点实验室
作者单位	1.Univ Milano Bicocca, Dept Earth & Environm Sci, Lab Provenance Studies, Piazza Sci 4, I-20126 Milan, Italy 2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Garzanti, Eduardo,Wang, Jiang-Gang,Vezzoli, Giovanni,et al. Tracing provenance and sediment fluxes in the Irrawaddy River basin (Myanmar)[J]. CHEMICAL GEOLOGY,2016,440:73-90.
APA	Garzanti, Eduardo,Wang, Jiang-Gang,Vezzoli, Giovanni,&Limonta, Mara.(2016).Tracing provenance and sediment fluxes in the Irrawaddy River basin (Myanmar).CHEMICAL GEOLOGY,440,73-90.
MLA	Garzanti, Eduardo,et al."Tracing provenance and sediment fluxes in the Irrawaddy River basin (Myanmar)".CHEMICAL GEOLOGY 440(2016):73-90.