scholarly journals Mesozoic evolution of the eastern Pamir

Lithosphere ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 560-580 ◽  
Author(s):  
Daniel B. Imrecke ◽  
Alexander C. Robinson ◽  
Lewis A. Owen ◽  
Jie Chen ◽  
Lindsay M. Schoenbohm ◽  
...  

Abstract We present field and analytical results from the Tashkurgan and Waqia valleys in the southeastern Pamir that shed new light on the tectonic evolution and terrane architecture of the region. Field mapping of metasedimentary and igneous units along the Tashkurgan and Waqia valleys in the Southeast Pamir, integrated with metamorphic petrology, garnet-biotite thermometry, and zircon U/Pb isotopic analysis, help identify major structures and terrane boundaries in the region, as well as compare structural units across the Miocene Muztaghata gneiss dome. South of the Muztaghata dome, the gently northwest-plunging synformal Torbashi thrust klippe juxtaposes amphibolite facies Triassic Karakul-Mazar terrane schist and gneiss structurally above (1) greenschist facies Triassic Karakul-Mazar terrane metasedimentary rock in the north, and (2) lower-amphibolite facies schist in the south that are interpreted to be Gondwanan-derived crust (Central or South Pamir terrane). Farther south, the Rouluke thrust fault imbricates the Gondwanan crust, placing early Paleozoic schists over Permian marble and slate. Exposure of the Torbashi thrust sheet terminates in the southeast, and with it the surface exposure of the Triassic Karakul-Mazar terrane, leaving the Paleozoic Kunlun terrane juxtaposed directly against Gondwanan terrane crust. Based on lithologic and isotopic similarities of units north and south of the Muztaghata gneiss dome, we document the existence of a regionally extensive thrust nappe that stretched across the northern and eastern Pamir, prior to being cut by Miocene exhumation of the Muztaghata dome. The thrust nappe links the Torbashi thrust in the southeast Pamir with the Tanymas thrust in the northern Pamir, and documents regionally extensive exposure of lithologically continuous units across the northeast Pamir. While timing of emplacement of the Torbashi thrust klippe and displacement on the Rouluke fault to the south is not well constrained, we interpret shortening to be Cretaceous in age based on previously published cooling ages. However, a component of Cenozoic shortening cannot be ruled out. A key observation from our mapping results is that the surface exposures of the Karakul–Mazar–Songpan Ganzi terrane are not continuous between western Tibet and the Pamir, which indicates tectonic and/or erosional removal, likely sometime in the Mesozoic. Furthermore, our documentation of the Jinsha suture in the southeast Pamir on the eastern side of the Karakoram fault shows deflections of terranes across the Himalayan-Tibetan orogen were not primarily accommodated along discrete, large displacement faults (>400 km) faults. Instead, oroclinal bending of the northern Pamir, and dextral shear along the Pamir margins, may be largely responsible for the northward deflection of terranes.

Author(s):  
Chen Wu ◽  
Jie Li ◽  
Andrew V. Zuza ◽  
Peter J. Haproff ◽  
Xuanhua Chen ◽  
...  

The Proterozoic−Phanerozoic tectonic evolution of the Qilian Shan, Qaidam Basin, and Eastern Kunlun Range was key to the construction of the Asian continent, and understanding the paleogeography of these regions is critical to reconstructing the ancient oceanic domains of central Asia. This issue is particularly important regarding the paleogeography of the North China-Tarim continent and South China craton, which have experienced significant late Neoproterozoic rifting and Phanerozoic deformation. In this study, we integrated new and existing geologic field observations and geochronology across northern Tibet to examine the tectonic evolution of the Qilian-Qaidam-Kunlun continent and its relationships with the North China-Tarim continent to the north and South China craton to the south. Our results show that subduction and subsequent collision between the Tarim-North China, Qilian-Qaidam-Kunlun, and South China continents occurred in the early Neoproterozoic. Late Neoproterozoic rifting opened the North Qilian, South Qilian, and Paleo-Kunlun oceans. Opening of the South Qilian and Paleo-Kunlun oceans followed the trace of an early Neoproterozoic suture. The opening of the Paleo-Kunlun Ocean (ca. 600 Ma) occurred later than the opening of the North and South Qilian oceans (ca. 740−730 Ma). Closure of the North Qilian and South Qilian oceans occurred in the Early Silurian (ca. 440 Ma), whereas the final consumption of the Paleo-Kunlun Ocean occurred in the Devonian (ca. 360 Ma). Northward subduction of the Neo-Kunlun oceanic lithosphere initiated at ca. 270 Ma, followed by slab rollback beginning at ca. 225 Ma evidenced in the South Qilian Shan and at ca. 194 Ma evidenced in the Eastern Kunlun Range. This tectonic evolution is supported by spatial trends in the timing of magmatism and paleo-crustal thickness across the Qilian-Qaidam-Kunlun continent. Lastly, we suggest that two Greater North China and South China continents, located along the southern margin of Laurasia, were separated in the early Neoproterozoic along the future Kunlun-Qinling-Dabie suture.


2019 ◽  
Author(s):  
Hamed D. Ibrahim

North and South Atlantic lateral volume exchange is a key component of the Atlantic Meridional Overturning Circulation (AMOC) embedded in Earth’s climate. Northward AMOC heat transport within this exchange mitigates the large heat loss to the atmosphere in the northern North Atlantic. Because of inadequate climate data, observational basin-scale studies of net interbasin exchange between the North and South Atlantic have been limited. Here ten independent climate datasets, five satellite-derived and five analyses, are synthesized to show that North and South Atlantic climatological net lateral volume exchange is partitioned into two seasonal regimes. From late-May to late-November, net lateral volume flux is from the North to the South Atlantic; whereas from late-November to late-May, net lateral volume flux is from the South to the North Atlantic. This climatological characterization offers a framework for assessing seasonal variations in these basins and provides a constraint for climate models that simulate AMOC dynamics.


Zootaxa ◽  
2020 ◽  
Vol 4758 (1) ◽  
pp. 45-82 ◽  
Author(s):  
L. LEE GRISMER ◽  
PERRY L. JR. WOOD ◽  
EVAN S. H. QUAH ◽  
MYINT KYAW THURA ◽  
JAMIE R. OAKS ◽  
...  

An integrative taxonomic analysis based on morphology, color pattern, and the mitochondrial gene ND2 recovered four new species of Hemiphyllodactylus Bleeker that are endemic to the Shan Plateau or Salween Basin in eastern Myanmar. Hemiphyllodactylus ngwelwini sp. nov. from the Shan Plateau is part of the earlier described “eastern Myanmar clade” renamed herein as the north lineage and H. kyaiktiyoensis sp. nov. and H. pinlaungensis sp. nov. of the Shan Plateau and H. zwegabinensis sp. nov. of the Salween Basin compose an entirely new Burmese clade herein referred to as the south lineage. Although the north and south lineages come within 46 km of one another on the Shan Plateau, they are not sister lineages but sequentially separated by two lineages from Yunnan, China and another from northwestern Thailand. Hemiphyllodactylus zwegabinensis sp. nov. is the first species of this genus to be recorded from the Salween Basin and is known only from a wind-blown cloud forest on the top of the insular, karstic mountain Zwegabin in Kayin State. All other Burmese species except for H. typus, are endemic to the various localities throughout the Shan Plateau. These four new species bring the total number of Hemiphyllodactylus in Myanmar to at least 10 which is certainly an extreme underestimate of the diversity of this genus given that we discover new species at every upland locality we survey. 


2020 ◽  
Vol 91 (5) ◽  
pp. 535-552
Author(s):  
Astrid Wood

In the post-colonial context, the global South has become the approved nomenclature for the non-European, non-Western parts of the world. The term promises a departure from post-colonial development geographies and from the material and discursive legacies of colonialism by ostensibly blurring the bifurcations between developed and developing, rich and poor, centre and periphery. In concept, the post-colonial literature mitigates the disparity between cities of the North and South by highlighting the achievements of elsewhere. But what happens when we try to teach this approach in the classroom? How do we locate the South without relying on concepts of otherness? And how do we communicate the importance of the South without re-creating the regional hierarchies that have dominated for far too long? This article outlines the academic arguments before turning to the opportunities and constraints associated with delivering an undergraduate module that teaches post-colonial concepts without relying on colonial constructs.


Author(s):  
Stefan Nygård

The history of modern Italy is an illustrative example of the different social and spatial layers of the North–South divide. Since unification in 1861, Italy has struggled to overcome regional imbalances, mainly although not exclusively along a North–South axis. With an emphasis on the period following unification, when North-South was placed at the centre of national politics, this chapter surveys the lingering debates on Italy’s so-called Southern question and the dynamics of nation-state formation in which it is embedded. The contested history of this process includes debates over economic and moral debts caused by the uneven distribution of gains and sacrifices between North and South as a result of unification. Socio-economically, two North–South divides developed in parallel after unification; the more significant one between Italy and transalpine Europe, and the initially minor but eventually growing divergence between the northern and southern regions within Italy. The ideas of development, catching-up and “Europeanization” were recurring themes in the intellectual and political debates discussed in the chapter. The contested issue was whether the North was developing the South, or vice versa.


2020 ◽  
Vol 40 (4) ◽  
pp. 384-389
Author(s):  
Satoshi Suyama ◽  
Shigeho Kakehi ◽  
Takashi Yanagimoto ◽  
Seinen Chow

Abstract The Pacific saury (Cololabis saira) is a fish of commercial importance subject to unpredictable epidemics of infection by Pennella sp., a parasitic copepod. We analyzed the distribution of fish presenting with newly attached Pennella to determine the region and season in which Pennella first infect the fish. Pacific sauries migrate northward in the spring to spend the summer in the subarctic region, successively crossing the Subarctic Boundary (SAB) and the Subarctic Front (SAF). The fish then return to subtropical waters in the fall and overwinter there. Pacific sauries infected with Pennella were observed on both the north and south sides of the SAF from May to December. Newly attached Pennella, however, were observed mainly to the south of the SAF during the northward migration of the fish in May and June, and only to the south of the SAB during the southward migration in November and December. These results indicate that the intermediate host or hosts of Pennella inhabit the region south of the SAF, with infection of Pacific saury occurring during late fall and spring. Such information may assist in identifying the intermediate host(s).


2016 ◽  
Vol 3 (2) ◽  
pp. 46
Author(s):  
Ghorbanali Ebrahimi ◽  
Hadi Razeghimaleh

<p>The main objective of this study was to find out whether social capital and its dimensions affect the cultural capital of citizens in Tehran, and whether there is any difference in the social capital and cultural capital in the north and south urban neighborhoods. To answer these questions, a fuzzy questionnaire for collecting the data was designed. The research method in this study was based on Artificial Neural Network -Fuzzy Inference System (ANNFIS). Statistical population included individuals aged 18 and above residing in Tehran, and sample size consisted of 2538 people.</p><p>The findings of this study indicated that there is a significant difference in the cultural capital between north and south neighborhoods in Tehran. The mean of cultural capital in the south neighborhoods (2.49 out of 10) was higher than that of north neighborhoods (6.77 out of 10). Furthermore, the degree of neighborhood social capital was different between the north and south neighborhoods of Tehran, and this difference was statistically significant, so that the mean of social capital in the south neighborhoods (6.75 out of 10) was greater than that of north neighborhoods (2.88 out of 10).</p>Multivariate linear regression analysis to explain cultural capital has revealed that social trust (- 0.502) and relation networks (- 0.087) exerted the highest and lowest impact on the dependent variable, respectively. It should be noted that, of the three variables entered into the regression equation, all variables have remained in the equation. It should be noted that the effects of all variables on the dependent variable of cultural capital was negative.


PMLA ◽  
2011 ◽  
Vol 126 (3) ◽  
pp. 685-692
Author(s):  
Nguyễn-Võ Thu-Hương

Whoever goes down to Bà Ria and happens by the cemetery in the sand at the village of Phu'ó'c Lě, I beg you to go in that cemetery and look for the grave with a cross painted half black, half white, by the side of the Church of Martyrs–to visit that grave lest it become pitiful. Because it has been two years since anyone visited or cast as much as a glance.—Nguyễn Trong QuanSO opens nguyễn trọng quản's thẩy lazaro phiển (“lazaro phiển” 22). The narrative begins at an obscure gravesite evokes the life of a man as both victim of state violence and perpetrator of private deaths. Lazaro Phiển is a ictional work written in the romanized script and was published in Saigon in 1887 in a novelistic format almost forty years before Hoàng Ngọc Phách's Tố Tâm. Yet the latter, published in Hanoi in 1925, is oten touted in official literary history as the first modern Vietnamese novel. Although Nguyễn Trọng Qu.n's narrative revolves around the recovery of an elided story, the author could not have anticipated the elision of his work from a nationalist literary genealogy that locates the origin of modern Vietnamese literature in the North. he elision was part of a general omission of works from the South in the last decades of the nineteenth century and irst two decades of the twentieth. his genealogy was by no means limited to the Democratic Republic of Vietnam in the North but was also perpetuated in the Republic of Vietnam in the South ater independence and the partitioning of the country into North and South in 1954


1997 ◽  
Vol 31 (1) ◽  
pp. 69-78
Author(s):  
ANNETTE TREFZER

The conflicted racial identity politics of Zora Neale Hurston climaxed in a statement printed in February 1943 in the New York Herald Telegram. In the article, “When Negro Succeeds, South is Proud,” Hurston argued that “the Jim Crow system works.” Hurston later retracted this statement, claiming that it was taken out of context and grossly distorted. Hurston said that her point was to show that “there was plenty of race prejudice both north and south” but that the South “by opportunity of long practice had worked out a system, while the North, caught between declarations of no prejudice, and its actual feelings [ctdot ] was groping around for the same thing, but with fine phrases.”


2004 ◽  
Vol 175 (2) ◽  
pp. 157-174 ◽  
Author(s):  
Jean-Baptiste Auréjac ◽  
Gérard Gleizes ◽  
Hervé Diot ◽  
Jean-Luc Bouchez

Abstract The Variscan Querigut Pluton (eastern Axial Zone, Pyrenees), recently dated at 307 ± 2 Ma, is a classical example for the structural study of granitoids. We present a new structural analysis of this pluton using the powerful technique of magnetic susceptibility anisotropy (AMS). A model of pluton emplacement is proposed on the basis of complementary microstructural analyses allowing the determination of the temperatures of fabric acquisition in the magmatic units, and of the shear sense criteria in the surrounding country rocks. This pluton is constituted by two main units that have intruded metasedimentary rocks where regional metamorphic conditions decrease from southwest to northeast. A well-foliated southern granodioritic unit, rich in Devonian marble xenoliths, is bounded to the south by Cambro-Ordovician metapelites. A weakly foliated northern monzogranitic unit, bounded to the north by Devonian marbles, comprises two sub-types : an outer biotite-monzogranite and an inner biotite-muscovite leucomonzogranite. Abundant basic stocks of variable sizes and lithologies outcrop in the granodioritic unit and in the southern part of the monzogranitic unit. Mean magnetic susceptibility and magnetic foliation maps show a very good agreement with the previous compiled petrographic and structural maps, strengthening the validity of the AMS technique. The northern monzogranitic units display two unevenly distributed structural patterns : (a) a NE-SW-trending pattern of weakly to steeply dipping foliations, dominant in the outer biotite monzogranite, is associated to subhorizontal NE-SW lineations ; and (b) a NW-SE-trending pattern of steeply dipping foliations, dominant in the inner biotite-muscovite monzogranite, is concentrated in NW-SE elongated corridors, associated to subhorizontal NW-SE lineations. In the southern granodioritic unit, foliation patterns follow roughly both the main regional foliation pattern and the pluton boundary, with foliation dips increasing to the south. Subhorizontal NW-SE trending magnetic lineations in the inner parts of this unit, are progressively verticalized toward the southern pluton boundary. A progressive increase in total magnetic anisotropy is observed toward the border of the pluton, correlated with both an increase in solid-state deformation and a decrease of the final temperature of fabric acquisition. These features result from a pluri-kilometric shear zone localized in the western half of the granodioritic unit, decreasing in thickness in its eastern half and along N060oE trending contacts with the country rocks. In the northern monzogranitic unit, one can roughly correlate the magmatic microstructures to the NE-SW trending fabric, and the superimposed subsolidus microstructures to the NW-SE-trending corridors, where rather low-temperature (&lt; 300 oC) fluid-assisted cataclastic microstructures may also appear. The country-rocks, half kilometer away from the pluton border, display the D2 regional Variscan pattern, with subvertical and N110oE-striking foliations and subhorizontal and E-W-trending stretching lineations associated to a dextral shear. Closer to the pluton, the country-rocks are subjected to the pluton influence, particularly along the southern border where a strong flattening is associated to subvertical lineations related to local thrusting of the pluton onto its country rocks. An emplacement model is proposed through the injection of three principal magma batches (granodiorite, biotite-monzogranite and biotite-muscovite monzogranite) that successively and progressively built up the pluton while the whole region was subjected to a dextral and compressive deformation regime, in agreement with AMS results obtained from several other plutons of the Pyrenees.


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