The LA-ICPMS zircon U-Pb geochronology of three typically Indosinian granitic plutons yielded weighted mean ^206pb/^238U ages of 214.1±5.9 Ma and 210.3±4.7 Ma for the biotite monzonitic granites from the Xie...The LA-ICPMS zircon U-Pb geochronology of three typically Indosinian granitic plutons yielded weighted mean ^206pb/^238U ages of 214.1±5.9 Ma and 210.3±4.7 Ma for the biotite monzonitic granites from the Xiema and Xiangzikou plutons in Hunan Province, and 205.3±1.6 Ma for biotite granite from the Napeng pluton, western Guandong Province, respectively, showing a similar late Indosinian age of crystallization. In combination with other geochronological data from Indosinian granites within the South China Block （SCB）, it is proposed that those late Indosinian granites with an age of -210 Ma and the early Indosinian granites （230-245 Ma） have the similar petrogenesis in identical tectonic setting. The Indosinian granites within the SCB might be the products of anatexis of the thickening crust in a compressive regime. These data provide a further understanding for the temporal and spatial distribution of the Indosinian granites and the dynamic evolution of the SCB.展开更多
Since the Cenozoic,the Tibetan Plateau has experienced large-scale uplift and outgrowth due to the India-Asia collision.However,the mechanism and timing of these tectonic processes still remain debated.Here,using apat...Since the Cenozoic,the Tibetan Plateau has experienced large-scale uplift and outgrowth due to the India-Asia collision.However,the mechanism and timing of these tectonic processes still remain debated.Here,using apatite fission track dating and inverse thermal modeling,we explore the mechanism of different phases of rapid cooling for different batholiths and intrusions in the southeastern Tibetan Plateau.In contrast to previous views,we find that the coeval granitic batholith exposed in the same tectonic zone experienced differential fast uplift in different sites,indicating that the present Tibetan Plateau was the result of differential uplift rather than the entire lithosphere uplift related to lithospheric collapse during Cenozoic times.In addition,we also suggest that the 5-2 Ma mantle-related magmatism should be regarded as the critical trigger for the widely coeval cooling event in the southeastern Tibetan Plateau,because it led to the increase in atmospheric CO_(2)level and a hotter upper crust than before,which are efficient for suddenly fast rock weathering and erosion.Finally,we propose that the current landform of the southeastern Tibetan Plateau was the combined influences of tectonic and climate.展开更多
The SHRIMP zircon U-Pb geochronology of three typical samples,including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang,western...The SHRIMP zircon U-Pb geochronology of three typical samples,including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang,western Yunnan Province.The analyses of zircons for the biotite monzonitic granites from the northern(02DX-137)and southern(20JH-10)Lincang batholith show the single and tight clusters on the concordia,and yield the weighted mean 206Pb/238U ages of 229.4±3.0 Ma and 230.4±3.6 Ma,respectively,representing the crystallized ages of these granites.The zircons for the rhyolitic sample(02DX-95)from the Manghuai Formation give a weighted mean 206Pb/238U age of 231.0±5.0 Ma.These data suggest that the igneous rocks from the Lincang granitic batholith and Manghuai Formation have a similar crystallized age.In combination with other data,it is inferred that both were generated at a narrow age span(~230 Ma)and were originated from the postcollisional tectonic regime.An early Proterozoic 206Pb/238U apparent age of 1977±44 Ma is additionally obtained from one zircon from the biotite monzonitic granite(southern Lincang batholith),indicative of devel-opment of the early Proterozoic Yangtze basement in the region.These precisely geochronological data provide important constraints on better understanding the Paleozoic tectonic evolution of the Tethys,western Yunnan Province.展开更多
基金This study was financially supported by the National Natural Science Foundation of China(grants 40421303 and 40234046).
文摘The LA-ICPMS zircon U-Pb geochronology of three typically Indosinian granitic plutons yielded weighted mean ^206pb/^238U ages of 214.1±5.9 Ma and 210.3±4.7 Ma for the biotite monzonitic granites from the Xiema and Xiangzikou plutons in Hunan Province, and 205.3±1.6 Ma for biotite granite from the Napeng pluton, western Guandong Province, respectively, showing a similar late Indosinian age of crystallization. In combination with other geochronological data from Indosinian granites within the South China Block （SCB）, it is proposed that those late Indosinian granites with an age of -210 Ma and the early Indosinian granites （230-245 Ma） have the similar petrogenesis in identical tectonic setting. The Indosinian granites within the SCB might be the products of anatexis of the thickening crust in a compressive regime. These data provide a further understanding for the temporal and spatial distribution of the Indosinian granites and the dynamic evolution of the SCB.
基金supported by National Natural Science Foundation of China(Grant Nos.42025301,41730213 and 41890831)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0702)+2 种基金Hong Kong RGC GRF(Grant No.17307918)HKU Internal Grants for Member of Chinese Academy of Sciences(Grant No.102009906)for Distinguished Research Achievement Award(Grant No.102010100)。
文摘Since the Cenozoic,the Tibetan Plateau has experienced large-scale uplift and outgrowth due to the India-Asia collision.However,the mechanism and timing of these tectonic processes still remain debated.Here,using apatite fission track dating and inverse thermal modeling,we explore the mechanism of different phases of rapid cooling for different batholiths and intrusions in the southeastern Tibetan Plateau.In contrast to previous views,we find that the coeval granitic batholith exposed in the same tectonic zone experienced differential fast uplift in different sites,indicating that the present Tibetan Plateau was the result of differential uplift rather than the entire lithosphere uplift related to lithospheric collapse during Cenozoic times.In addition,we also suggest that the 5-2 Ma mantle-related magmatism should be regarded as the critical trigger for the widely coeval cooling event in the southeastern Tibetan Plateau,because it led to the increase in atmospheric CO_(2)level and a hotter upper crust than before,which are efficient for suddenly fast rock weathering and erosion.Finally,we propose that the current landform of the southeastern Tibetan Plateau was the combined influences of tectonic and climate.
基金supported by the National Natural Science Foundation of China(Grant Nos.40473019,40421303 and 40334039)the Chinese Academy of Sciences(Grant No.KZCXZ-SW-117).
文摘The SHRIMP zircon U-Pb geochronology of three typical samples,including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang,western Yunnan Province.The analyses of zircons for the biotite monzonitic granites from the northern(02DX-137)and southern(20JH-10)Lincang batholith show the single and tight clusters on the concordia,and yield the weighted mean 206Pb/238U ages of 229.4±3.0 Ma and 230.4±3.6 Ma,respectively,representing the crystallized ages of these granites.The zircons for the rhyolitic sample(02DX-95)from the Manghuai Formation give a weighted mean 206Pb/238U age of 231.0±5.0 Ma.These data suggest that the igneous rocks from the Lincang granitic batholith and Manghuai Formation have a similar crystallized age.In combination with other data,it is inferred that both were generated at a narrow age span(~230 Ma)and were originated from the postcollisional tectonic regime.An early Proterozoic 206Pb/238U apparent age of 1977±44 Ma is additionally obtained from one zircon from the biotite monzonitic granite(southern Lincang batholith),indicative of devel-opment of the early Proterozoic Yangtze basement in the region.These precisely geochronological data provide important constraints on better understanding the Paleozoic tectonic evolution of the Tethys,western Yunnan Province.
