气候变化领域集成服务门户(CCPortal): Petrological and geochemical variations of a turbidite-like metasedimentary sequence over the metatexite to diatexite transition within the Pampean Orogen; Argentina

CCPortal

DOI	10.1007/s00531-019-01711-z
	Petrological and geochemical variations of a turbidite-like metasedimentary sequence over the metatexite to diatexite transition within the Pampean Orogen; Argentina
	Otamendi J.E.; Barzola M.G.; Tibaldi A.M.; Cristofolini E.A.; Álvarez-Valero A.M.; Demichelis A.H.
发表日期	2019
ISSN	14373254
起始页码	1361
结束页码	1385
卷号	108 期号:4
英文摘要	Large masses of turbidite systems have been metamorphosed in orogenic systems during Earth’s history. Under granulite-facies conditions, the transformation of turbidite sedimentary successions into metasedimentary sequences drives intracrustal differentiation by anatexis and melt–residuum separation. We report on a migmatite terrane developing from turbidite successions that were buried into the deep crust during the Neoproterozoic to Early Cambrian Pampean orogeny, in central Argentina. At the exposed middle crustal paleodepths, migmatites occur on the regional scale but lithological zones are characterized by (1) bedded migmatites, (2) metatexite, and (3) diatexite. Bedded migmatites are the low-temperature part of the migmatite terrane where the alternating metapelite and metagreywacke layers are traceable among migmatites of different protoliths. The temperature (> 790 °C) was sufficient high for melting the metapelite, but not for melting the metagreywacke. The majority of the migmatite terrane consists of stromatic metatexites in which the limit among different progenitors is either faint or erased by migmatization. Metatexite zone acts as melt transfer in the migmatite terrane. In the stromatic migmatites, the major oxide composition of leucosomes and tabular bodies of leucogranite resembles those of the glasses of experimental petrology. However, leucosomes and leucogranites are crystallized melts that have low Zr, Th and LREE contents and positive Eu anomalies resulting from accessory mineral retention in melting residues. The transformation of metatexite into diatexite is gradational over tens of metres, and related to an accumulated melt fraction that dismembers the stromatic fabric. The most abundant diatexite is mesocratic, and has little or lacks K-feldspar. A subordinate proportion of diatexites is leucocratic, contains K-feldspar phenocrysts, and shows igneous-like textures. Leucogranites and leucocratic diatexites are the potential carriers of an anatectic melt-rich component from granulite-facies migmatite sequences toward shallow crustal levels. Turbidite successions are fertile protoliths that undergo widespread melting under low granulite-facies temperature (< 850 °C), and the development of large diatexite massifs makes them suitable sources of granitic magmatism. © 2019, Geologische Vereinigung e.V. (GV).
英文关键词	Crustal anatexis; Diatexite; Metatexite; Migmatite; Sierras Pampeanas
语种	英语
scopus关键词	anatexis; crustal structure; metasediment; migmatite; orogeny; petrology; sediment chemistry; sedimentary sequence; turbidite; Argentina
来源期刊	International Journal of Earth Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/147838
作者单位	Consejo Nacional de Investigaciones Científicas y Técnicas, Departamento de Geología, Universidad Nacional de Río Cuarto, Campus Universitario, Río Cuarto, X5804BYA, Argentina; Departamento de Geología, Universidad de Salamanca, Plaza de la Merced, Salamanca, 37008, Spain
推荐引用方式 GB/T 7714	Otamendi J.E.,Barzola M.G.,Tibaldi A.M.,et al. Petrological and geochemical variations of a turbidite-like metasedimentary sequence over the metatexite to diatexite transition within the Pampean Orogen; Argentina[J],2019,108(4).
APA	Otamendi J.E.,Barzola M.G.,Tibaldi A.M.,Cristofolini E.A.,Álvarez-Valero A.M.,&Demichelis A.H..(2019).Petrological and geochemical variations of a turbidite-like metasedimentary sequence over the metatexite to diatexite transition within the Pampean Orogen; Argentina.International Journal of Earth Sciences,108(4).
MLA	Otamendi J.E.,et al."Petrological and geochemical variations of a turbidite-like metasedimentary sequence over the metatexite to diatexite transition within the Pampean Orogen; Argentina".International Journal of Earth Sciences 108.4(2019).