scholarly journals Supplemental Material: Cambrian magmatic flare-up, central Tibet: Magma mixing in proto-Tethyan arc along north Gondwanan margin

2021 ◽  
Author(s):  
Pei-yuan Hu ◽  
et al.
Keyword(s):  
Tibetan Plateau ◽  
Analytical Methods ◽  
Magma Mixing ◽  
Mixing Model ◽  
Lhasa Terrane ◽  
The North ◽  
Magmatic Rocks ◽  
Central Tibetan Plateau ◽  
Central Tibet

Data, magma mixing model, and analytical methods of the Cambrian magmatic rocks from the North Lhasa terrane, central Tibetan Plateau.

scholarly journals Supplemental Material: Cambrian magmatic flare-up, central Tibet: Magma mixing in proto-Tethyan arc along north Gondwanan margin

2021 ◽  
Author(s):  
Pei-yuan Hu ◽  
et al.
Keyword(s):  
Tibetan Plateau ◽  
Analytical Methods ◽  
Magma Mixing ◽  
Mixing Model ◽  
Lhasa Terrane ◽  
The North ◽  
Magmatic Rocks ◽  
Central Tibetan Plateau ◽  
Central Tibet

Data, magma mixing model, and analytical methods of the Cambrian magmatic rocks from the North Lhasa terrane, central Tibetan Plateau.

Cambrian magmatic flare-up, central Tibet: Magma mixing in proto-Tethyan arc along north Gondwanan margin

2021 ◽  
Author(s):  
Pei-yuan Hu ◽  
Qing-guo Zhai ◽  
Peter A. Cawood ◽  
Guo-chun Zhao ◽  
Jun Wang ◽  
...  
Keyword(s):  
Magma Mixing ◽  
Geochemical Data ◽  
Early Paleozoic ◽  
East African ◽  
Lhasa Terrane ◽  
The North ◽  
Magmatic Rocks ◽  
East African Orogen ◽  
Andean Type ◽  
Central Tibet

Accompanying Gondwana assembly, widespread but diachronous Ediacaran−early Paleozoic magmatism of uncertain origin occurred along the supercontinent’s proto-Tethyan margin. We report new geochemical, isotopic, and geochronological data for Cambrian magmatic rocks (ca. 500 Ma) from the Gondwana-derived North Lhasa terrane, located in the present-day central Tibetan Plateau. The magmatic rocks are composed of basalts, gabbros, quartz monzonites, granitoids (with mafic microgranular enclaves), and rhyolites. Nd-Hf isotopic and whole-rock geochemical data indicate that these rocks were probably generated by mixing of mantle-derived mafic and crust-derived felsic melts. The mantle end-member volumes of mafic, intermediate, and felsic rocks are ∼75%−100%, 50%−60%, and 0−30%, respectively. Integration of our new data with previous studies suggests that the North Lhasa terrane experienced long-term magmatism through the Ediacaran to Ordovician (ca. 572−483 Ma), with a magmatic flare-up at ca. 500 Ma. This magmatism, in combination with other Ediacaran−early Paleozoic magmatism along the proto-Tethyan margin, was related to an Andean-type arc, with the magmatic flare-up event related to detachment of the oceanic slab following collisional accretion of Asian microcontinental fragments to northern Gondwana. Diachroneity of the proto-Tethyan arc system along the northern Gondwanan margin (ca. 581−531 Ma along the Arabian margin and ca. 512−429 Ma along the Indian-Australian margin) may have been linked to orogenesis within Gondwana. The North Lhasa terrane was probably involved in both Arabian and Indian-Australian proto-Tethyan Andean-type orogens, based on its paleogeographic location at the northern end of the East African orogen.

First mid-ocean ridge-type ophiolite from the Meso-Tethys suture zone in the north-central Tibetan plateau

2020 ◽  
Vol 132 (9-10) ◽  
pp. 2202-2220 ◽  
Author(s):  
Yue Tang ◽  
Qing-Guo Zhai ◽  
Sun-Lin Chung ◽  
Pei-Yuan Hu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Ocean Basin ◽  
Suture Zone ◽  
The Tibetan Plateau ◽  
Spreading Ridge ◽  
North Central ◽  
The North ◽  
Central Tibetan Plateau ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

Abstract The Meso-Tethys was a late Paleozoic to Mesozoic ocean basin between the Cimmerian continent and Gondwana. Part of its relicts is exposed in the Bangong–Nujiang suture zone, in the north-central Tibetan Plateau, that played a key role in the evolution of the Tibetan plateau before the India-Asia collision. A Penrose-type ophiolitic sequence was newly discovered in the Ren Co area in the middle of the Bangong–Nujiang suture zone, which comprises serpentinized peridotites, layered and isotropic gabbros, sheeted dikes, pillow and massive basalts, and red cherts. Zircon U-Pb dating of gabbros and plagiogranites yielded 206Pb/238U ages of 169–147 Ma, constraining the timing of formation of the Ren Co ophiolite. The mafic rocks (i.e., basalt, diabase, and gabbro) in the ophiolite have uniform geochemical compositions, coupled with normal mid-ocean ridge basalt-type trace element patterns. Moreover, the samples have positive whole-rock εNd(t) [+9.2 to +8.3], zircon εHf(t) [+17 to +13], and mantle-like δ18O (5.8–4.3‰) values. These features suggest that the Ren Co ophiolite is typical of mid-ocean ridge-type ophiolite that is identified for the first time in the Bangong–Nujiang suture zone. We argue that the Ren Co ophiolite is the relic of a fast-spreading ridge that occurred in the main oceanic basin of the Bangong–Nujiang segment of Meso-Tethys. Here the Meso-Tethyan orogeny involves a continuous history of oceanic subduction, accretion, and continental assembly from the Early Jurassic to Early Cretaceous.

scholarly journals Precipitation record since AD 1600 from ice cores on the central Tibetan Plateau

2008 ◽  
Vol 4 (3) ◽  
pp. 175-180 ◽  
Author(s):  
T. Yao ◽  
K. Duan ◽  
B. Xu ◽  
N. Wang ◽  
X. Guo ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Ice Core ◽  
Ice Cores ◽  
The North ◽  
Northern Tibetan Plateau ◽  
Central Tibetan Plateau ◽  
Precipitation Record ◽  
Ice Field ◽  
The 19Th Century

Abstract. Lack of reliable long-term precipitation record from the northern Tibetan Plateau has constrained our understanding of precipitation variations in this region. We drilled an ice core on the Puruogangri Ice Field in the central Tibetan Plateau in 2000 to reveal the precipitation variations. The well dated part of the core extends back to AD 1600, allowing us to construct a 400-year annual accumulation record. This record shows that the central Tibetan plateau experienced a drier period with an average annual precipitation of ~300 mm in the 19th century, compared to ~450 mm in the wetter periods during 1700–1780 and the 20th century. This pattern agrees with precipitation reconstructions from the Dunde and Guliya ice cores on the northern Plateau but differs from that found in the Dasuopu ice cores from the southern Plateau The north-south contrasts in precipitation reconstruction reveals difference in moisture origin between the south Tibetan Plateau dominated by the Asian monsoon and the north Tibetan Plateau dominated by the continental recycling and the westerlies.

Middle Neoproterozoic magmatic event in the western Nam Tso area, Tibetan Plateau: Constraint on the origin of the North Lhasa terrane

2019 ◽  
Vol 35 (10) ◽  
pp. 3115-3129 ◽  
Author(s):  
HU PeiYuan ◽  
◽  
ZHAI QingGuo ◽  
ZHAO GuoChun ◽  
TANG Yue ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Lhasa Terrane ◽  
The North ◽  
Magmatic Event

Triassic calc-alkaline lamprophyre dykes from the North Qiangtang, central Tibetan Plateau: evidence for a subduction-modified lithospheric mantle

2021 ◽  
pp. 1-14
Author(s):  
Bin Liu ◽  
You-Jun Tang ◽  
Lü-Ya Xing ◽  
Yu Xu ◽  
Shao-Qing Zhao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Oceanic Lithosphere ◽  
Late Triassic ◽  
The North ◽  
Deep Crust ◽  
Central Tibetan Plateau ◽  
Low Degree ◽  
Peridotite Mantle ◽  
Orogenic Belts ◽  
Isotopic Variations

Abstract Primitive lamprophyres in orogenic belts can provide crucial insights into the nature of the subcontinental lithosphere and the relevant deep crust–mantle interactions. This paper reports a suite of relatively primitive lamprophyre dykes from the North Qiangtang, central Tibetan Plateau. Zircon U–Pb ages of the lamprophyre dykes range from 214 Ma to 218 Ma, with a weighted mean age of 216 ± 1 Ma. Most of the lamprophyre samples are similar in geochemical compositions to typical primitive magmas (e.g. high MgO contents, Mg no. values and Cr, with low FeOt/MgO ratios), although they might have experienced a slightly low degree of olivine crystallization, and they show arc-like trace-element patterns and enriched Sr–Nd isotopic composition ((87Sr/86Sr)i = 0.70538–0.70540, ϵNd(t) = −2.96 to −1.65). Those geochemical and isotopic variations indicate that the lamprophyre dykes originated from partial melting of a phlogopite- and spinel-bearing peridotite mantle modified by subduction-related aqueous fluids. Combining with the other regional studies, we propose that slab subduction might have occurred during Late Triassic time, and the rollback of the oceanic lithosphere induced the lamprophyre magmatism in the central Tibetan Plateau.

scholarly journals Ice core precipitation record in central Tibetan plateau since AD 1600

2008 ◽  
Vol 4 (1) ◽  
pp. 233-248 ◽  
Author(s):  
T. Yao ◽  
K. Duan ◽  
B. Xu ◽  
N. Wang ◽  
X. Guo ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Ice Core ◽  
Precipitation Amount ◽  
Ice Cores ◽  
The North ◽  
Temperature And Precipitation ◽  
Northern Tibetan Plateau ◽  
Central Tibetan Plateau ◽  
Precipitation Record ◽  
High Precipitation

Abstract. Lack of reliable long-term precipitation record from northern Tibetan Plateau has constrained the understanding of precipitation variation in this region. An ice core drilled from the Puruogangri Ice Field on central Tibetan Plateau in the year 2000 helped reveal the precipitation variations since AD 1600. Analysis of the annual accumulation data presented precipitation changes from AD 1600, indicative of wet and dry periods in the past 400 year in the central Tibetan Plateau. Accordingly, the 18th and 20th centuries experienced high precipitation period, whilst the 19th century experienced low precipitation period. Such a feature was consistent with precipitation recorded in ice cores from Dunde and Guliya Glaciers, northern Tibetan Plateau. Besides, the results also pointed to consistency in precipitation-temperature correlation on the northern Tibetan Plateau, in a way that temperature and precipitation were positively correlated. But this feature was contrary to the relationship revealed from Dasuopu ice cores, southern Tibetan Plateau, where temperature and precipitation were negatively correlated. The north-south contrast in precipitation amount and its relationship with temperature may shed light on the reconstruction of Asian monsoon since AD 1600.

Precambrian origin of the North Lhasa terrane, Tibetan Plateau: Constraint from early Cryogenian back-arc magmatism

2018 ◽  
Vol 313 ◽  
pp. 51-67 ◽  
Author(s):  
Pei-yuan Hu ◽  
Qing-guo Zhai ◽  
Jun Wang ◽  
Yue Tang ◽  
Hai-tao Wang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Arc Magmatism ◽  
Lhasa Terrane ◽  
The North ◽  
Back Arc

scholarly journals A 70-yr record of oxygen-18 variability in accumulation from the Tanggula Mountains, central Tibetan Plateau

2009 ◽  
Vol 5 (4) ◽  
pp. 1929-1949
Author(s):  
D. R. Joswiak ◽  
T. Yao ◽  
G. Wu ◽  
B. Xu ◽  
W. Zheng
Keyword(s):  
Tibetan Plateau ◽  
Temperature Dependence ◽  
Ice Core ◽  
Warm Season ◽  
Ice Cores ◽  
Isotope Ratios ◽  
Significant Negative Correlation ◽  
Annual Average ◽  
The North ◽  
Central Tibetan Plateau

Abstract. A 33 m ice core was retrieved from the Tanggula Mtns, central Tibetan Plateau at 5743 m a.s.l. in August 2005. Annual average δ18O ratios were determined for the upper 17 m depth, representing the time series since the mid-1930's based on multi-parameter dating techniques. Data are compared to previous results (Kang et al., 2007) of an ice core from Mt. Geladaindong, 100 km to the northwest, for the period 1935–2003. During the time 1935–1960, δ18O ratios differed by 2–3‰ between the two ice cores, with generally lower ratios preserved in the Tanggula 2005 core. Differences in interannual variability and overall average ratios between the two study locations highlight the spatially variable climatic signals of ice core isotope ratios within the boundary of monsoon- and westerly-impacted regions of the central Tibetan Plateau. Average annual net accumulation was 261 mm w.eq. yr−1 for the period 1935–2004. Overall average δ18O ratio was −13.2‰ and exhibited a statistically significant increase from the 1935–1969 average (−413.7‰) to the 1970–2004 average (−12.6‰). Despite the observed increase in isotope ratios, temperature dependence was not found based on comparison with long-term data from meteorological stations to the north and southwest of the study location. Lack of temperature dependence is likely due monsoon influence, which results in relatively more depleted moisture arriving during the warm season. Evidence of monsoon impacts on precipitation in the central Tibetan Plateau has been previously documented, and statistically significant negative correlation (r=-0.37, p<0.01) between the annual average ice core δ18O ratio and N. India monsoon rainfall was observed for the period 1935–2004.

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