Middle Miocene paleoaltimetry of southern Tibet: Implications for the role of mantle thickening and delamination in the Himalayan orogen

Geology ◽  
2005 ◽  
Vol 33 (3) ◽  
pp. 181 ◽  
Author(s):  
Brian S. Currie ◽  
David B. Rowley ◽  
Neil J. Tabor
Keyword(s):  
Middle Miocene ◽  
Southern Tibet ◽  
Himalayan Orogen

Himalayan Miocene adakitic rocks, a case study of the Mayum pluton: Insights into geodynamic processes within the subducted Indian continental lithosphere and Himalayan mid-Miocene tectonic regime transition

2020 ◽  
Author(s):  
Chao Lin ◽  
Jinjiang Zhang ◽  
Xiaoxian Wang ◽  
Tianli Huang ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Middle Miocene ◽  
Continental Lithosphere ◽  
Southern Tibet ◽  
Himalayan Orogen ◽  
Tectonic Regime ◽  
Isotopic Compositions ◽  
Adakitic Rocks ◽  
Geodynamic Processes ◽  
T Values ◽  
Asthenospheric Upwelling

The Himalayan Orogen is a typical continental collision orogenic belt that formed during India-Asia collision. The orogeny involved a transition in tectonic regime, which led to E-W−trending extension during the middle Miocene. At the same time, widespread post-collisional adakitic magmatism occurred in southern Tibet, particularly in the Lhasa Terrane, and these rocks provide a valuable record of the collisional geodynamic processes within the lithosphere. Few studies have focused on the middle Miocene adakitic rocks of the Himalayan Orogen, so further research is required to constrain their origin and geodynamics. This study presents new geochronological and geochemical data, including the whole rock Sr-Nd and zircon Hf isotopic compositions from the Mayum pluton in the Mayum-Gong Tso area, Northern Himalaya. Zircon U-Pb ages show that the Mayum granodiorite porphyries crystallized at 16.67 ± 0.14 Ma (mean square weighted deviation [MSWD] = 0.82, n = 29) and 16.68 ± 0.16 Ma (MSWD = 1.13, n = 28), indicating that they formed during the middle Miocene. The major and trace element characteristics are as follows: SiO2 = 65.79−67.31 wt%, Al2O3 = 15.28−16.00 wt%, MgO = 1.77−1.89 wt%, Y = 12.0−13.5 ppm, Yb = 0.11−0.99 ppm, Sr = 719−822 ppm, (La/Yb)N = 21.89−27.02, Sr/Y = 56.1−65.5, and the rocks have weak negative Eu anomalies (Eu/Eu* = 0.76−0.85), indicating that they are adakitic rocks and show high Sr-Ba granite affinity. The Mayum granodiorite porphyries have high K2O contents (3.42−3.65 wt%), Na2O (3.76−4.04 wt%), and K2O/Na2O ratios of 0.91−0.95, indicating a high-K calc-alkaline affinity. All samples are enriched in large-ion lithophile elements and depleted in high field strength elements. The initial 87Sr/86Sr ratios are 0.709262−0.709327 and εNd(t) values are −6.36 to −7.07, which correspond to two-stage Nd model ages [TDM2(Nd)] of 1405−1348 Ma. In situ zircon Lu-Hf isotopic compositions are variable, with 176Hf/177Hf ratios of 0.2823845−0.282824, εHf(t) values of −13.37 to +2.17, and two-stage Hf model ages [TDM2(Hf)] of 1704−841 Ma. These geochemical and Sr-Nd-Hf isotopic characteristics indicate that the Mayum granodiorite porphyries may be derived from partial melting of the subducted Indian thickened ancient mafic lower crust (∼92%) mixed with depleted mid-ocean ridge basalt mantle material input (∼8%) slightly. Crust-mantle interaction was induced by asthenospheric upwelling followed by the underplating of the Himalayan lower crust beneath Southern Tibet during the middle Miocene in response to significant changes in the geodynamics of the India-Asia collisional orogen. These deep geodynamic processes reflect the break-off or rollback of the subducted Indian continental slab, which caused asthenospheric upwelling, the input of juvenile heat, and the addition of depleted mantle material. This study indicates that the middle Miocene Himalayan adakitic rocks, which include the Miocene Yardoi two-mica granite, Gyangzê granite porphyry dike, Bendui two-mica granite, Langkazi enclave, Kuday dacitic dike, Lasa pluton, and Mayum pluton, form a belt of adakitic rocks in the Northern Himalaya to the south of the Indus-Tsangpo Suture Zone. These adakitic rocks have similar temporal and spatial distributions, geochemical features, and Sr-Nd isotopic compositions, indicating that their petrogenesis and geodynamic settings were similar. At that time there was widespread initiation of N-S−trending rifting, exhumation of central Himalayan eclogites, and large changes in the compositions of Himalayan leucogranites in the Himalayan Orogen. These can be attributed to significant changes in the characteristics of the subducted Indian continental lithosphere during the middle Miocene. The middle Miocene Himalayan adakitic rocks provide valuable insights into this transition in the tectonic regime and deep geodynamic processes.

The role of clinopyroxene in amphibole fractionation of arc magmas: Evidence from mafic intrusive rocks within the Gangdese arc, southern Tibet

Lithos ◽  
2019 ◽  
Vol 338-339 ◽  
pp. 174-188 ◽  
Author(s):  
Jun Wang ◽  
Qiang Wang ◽  
Wei Dan ◽  
Jin-Hui Yang ◽  
Zong-Yong Yang ◽  
...  
Keyword(s):  
Southern Tibet ◽  
Arc Magmas ◽  
Intrusive Rocks ◽  
Amphibole Fractionation

Rapid denudation of the Himalayan orogen in the Nyalam area, southern Tibet, since the Pliocene and implications for tectonics–climate coupling

2014 ◽  
Vol 59 (9) ◽  
pp. 874-885 ◽  
Author(s):  
Yong Zheng ◽  
Jinjiang Zhang ◽  
Jiamin Wang ◽  
Bo Zhang ◽  
Xiaoxian Wang ◽  
...  
Keyword(s):  
Southern Tibet ◽  
Himalayan Orogen

Eocene–Oligocene granitoids in southern Tibet: Constraints on crustal anatexis and tectonic evolution of the Himalayan orogen

2012 ◽  
Vol 349-350 ◽  
pp. 38-52 ◽  
Author(s):  
Zeng-Qian Hou ◽  
Yuan-Chuan Zheng ◽  
Ling-Sen Zeng ◽  
Li-E Gao ◽  
Ke-Xian Huang ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Crustal Anatexis ◽  
Southern Tibet ◽  
Himalayan Orogen

Toward a Geographic Biography: Mi la ras pa in the Tibetan Landscape

Numen ◽  
2008 ◽  
Vol 55 (4) ◽  
pp. 363-410 ◽  
Author(s):  
Andrew Quintman
Keyword(s):  
Life Story ◽  
Southern Tibet ◽  
Sacred Place ◽  
Dialogical Relationship ◽  
Biographical Tradition

AbstractFew Tibetan figures have left an impression on the Himalayan landscape, both literary and geographic, as indelibly as Mi la ras pa (ca. 1028–1111), whose career as meditator and poet was punctuated by travel across the borderlands of southern Tibet. This essay will begin to address the defining role of place in Tibetan biographical literature by examining the intersections of text and terrain in the recording of an individual's life. In particular, this study examines sites of transformation in Mi la ras pa's biographical narratives, arguing for what might be called a geographic biography by examining the dialogical relationship between a life story recorded on paper and a life imprinted on the ground. It first considers the broad paradigms for landscaping the environment witnessed in Tibetan literature. It then examines ways in which the yogin's early biographical tradition treated the category of sacred place, creating increasingly detailed maps of the yogin's life, and how those maps were understood and reinterpreted. The paper concludes by addressing two specific modes of transformation in the life story — contested place and re-imagined place — exploring new geographies of consecration, dominion, and praxis.

scholarly journals Supplemental Material: Construction of the Lesser Himalayan–Subhimalayan thrust belt: The primary driver of thickening, exhumation, and high elevations in the Himalayan orogen since the middle Miocene

2021 ◽  
Author(s):  
Sean P. Long ◽  
Delores M. Robinson
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Middle Miocene ◽  
Thrust Belt ◽  
Himalayan Orogen ◽  
Primary Driver ◽  
High Elevations

Supplemental figures and tables that provide supporting data for the compiled cross sections and the measured parameters, as well as text that summarizes the tectonostratigraphic units on each cross section.<br>

scholarly journals Levels of changes in the genus Pinus Linné in the composition of Mesozoic and Cenozoic flora and vegetation as an additional criterion for the division of sediments by the Mesozoic and Cenozoic of Ukraine

2021 ◽  
Vol 30 (4) ◽  
pp. 741-753
Author(s):  
Olena A. Sirenko ◽  
Olena A. Shevchuk
Keyword(s):  
Species Diversity ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Middle Miocene ◽  
Geological Time ◽  
Tectonic Structures ◽  
Historical Aspect ◽  
Quantitative Changes ◽  
Cenozoic Sediments

The article presents an analysis of a large array of results of palynological studies of Mesozoic and Cenozoic sediments of Ukraine and adjacent regions of Belarus and Russia. Numerous literature data on the palynological characteristics of Meso-Cenozoic sediments and the materials of the authors are summarized according to the results of spore-pollen analysis of Mesozoic and Cenozoic sediments within the main tectonic structures of Ukraine. It has been established that the genus Pinus (Pinaceae) is an integral part of the Meso-Cenozoic flora of Ukraine. Although, the participation in the flora and vegetation of the genus Pinus and its species diversity in different periods of geological time were different. Despite the long history and significant achievements of palynological research of Meso-Cenozoic sediments of Ukraine, no attention has been paid to the historical aspect of Pinus development in the Meso-Cenozoic flora. This work is presented as the first stem to fill this gap. The genus Pinus has a large stratigraphic range, but its species diversity and quantitative changes in the composition of Mesozoic and Cenozoic flora of different ages are markedly different. The analysis of these changes made it possible to trace the emergence and main levels at which the species composition was renewed and the role of Pinus in flora increased during the Mesozoic and Cenozoic. According to the results of the research, 5 levels of increasing the participation of the genus Pinus and changes in its species affiliation in the Mesozoic flora were established: Aalenian period of the Middle Jurassic (appearance of the first representatives of Pinus); Oxfordian time of the Late Jurassic; Valanginian – Early Barremian times of the Early Cretaceous; Albian time of the Early Cretaceous; Late Campanian time of the Late Cretaceous. 5 levels of increasing the role of Pinus and its species diversity for the flora and vegetation of the Cenozoic were also established: Oligocene time of the Paleogene, Konkian-early Sarmatian time of the Middle Miocene; early Pontian (Ivankov) time of the Late Miocene; early Kimmerian time (early Sevastopol) of the Early Pliocene and Martonosha time of the Early Neopleistocene. Certain levels have been traced for the similar age of Cenozoic flora of Belarus and Russia.

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