Structure, age substantiation and tectonic setting of the Lower-Middle Ordovician volcanic-sedimentary and plutonic complexes of the western part of the Kyrgyz Range (Northern Tien Shan)

2012 ◽  
Vol 20 (4) ◽  
pp. 317-345 ◽  
Author(s):  
K. E. Degtyarev ◽  
T. Yu. Tolmacheva ◽  
A. V. Ryazantsev ◽  
A. A. Tret’yakov ◽  
A. S. Yakubchuk ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Tien Shan ◽  
Middle Ordovician ◽  
Northern Tien Shan

scholarly journals Tectonic structure and development of the “depression/ uplift” transition zones, Northern Tien Shan

2020 ◽  
Vol 65 (4) ◽  
Author(s):  
Eugeny S. Przhiyalgovskii ◽  
◽  
Yuriy A. Morozov ◽  
Mikhail G. Leonov ◽  
Anatoliy K. Rybin ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Lateral Pressure ◽  
Sedimentary Cover ◽  
Tectonic Setting ◽  
Structural Features ◽  
Tien Shan ◽  
Vertical Movements ◽  
Transition Zones ◽  
Basement Rocks ◽  
Northern Tien Shan

The article presents data on the structure of transition zones from areas of relative downwarping (intramountain depressions) to anticlinor uplifts dividing them. The geological and geophysical data obtained by the authors in recent years in different areas of the Northern Tien Shan are considering and discussing to compare the structure and tectonic evolution of key objects. A comparative analysis of the depression / uplift tectonic zones in different regions indicates a fundamental similarity in their structure. These areas of gradient vertical movements are zones of concentrated deformation. We described ensembles of structures formed at the same time in the sedimentary cover and in the basement rocks. Similar structural features are due to the common tectonic evolution of basins and ridges as parts of a unified activation structure of the Paleozoic folded belt. Over a long period of time, from the Oligocene to the Pliocene inclusive, the depressions of the Northern Tien Shan had developed under conditions of sedimentary subsidence, probably by the type of pool-apart structures in a latitudinally oriented region of plastic shear deformation. The relatively quiet tectonic setting of this stage is reflected in the lithological features of the sedimentary complexes. The next stage, which began about 3 Ma b.p., was marked not only by the emergence of a high-altitude relief and the accumulation of molasses, but also by a change of tectonic regime to transpression. The generally flexible bending of the foundation surface in the steep sides of the depressions, to some extent complicated by uplifts, was accompanied by the formation of extensive detachments and thrust-folded structural ensembles in the sedimentary cover of the depressions. Contrary to popular point of view volumes of disintegrated basement rocks demonstrate significant plasticity. The lateral pressure of the side ledges inside the sedimentary cover was transmitted for many kilometers towards the depression’s center. At the same time, contrary to traditional ideas, the volumes of disintegrated rocks of the basement demonstrate significant plasticity, while the lateral pressure of the side ledges was transmitted for many kilometers into the depressions inside the sedimentary cover.

scholarly journals High Mountain Asian glacier response to climate revealed by multi-temporal satellite observations since the 1960s

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Atanu Bhattacharya ◽  
Tobias Bolch ◽  
Kriti Mukherjee ◽  
Owen King ◽  
Brian Menounos ◽  
...  
Keyword(s):  
Mass Loss ◽  
River Flow ◽  
Tien Shan ◽  
High Mountain ◽  
Glacier Mass Balance ◽  
Temperature And Precipitation ◽  
Multi Temporal ◽  
The 1960S ◽  
Northern Tien Shan

AbstractKnowledge about the long-term response of High Mountain Asian glaciers to climatic variations is paramount because of their important role in sustaining Asian river flow. Here, a satellite-based time series of glacier mass balance for seven climatically different regions across High Mountain Asia since the 1960s shows that glacier mass loss rates have persistently increased at most sites. Regional glacier mass budgets ranged from −0.40 ± 0.07 m w.e.a−1 in Central and Northern Tien Shan to −0.06 ± 0.07 m w.e.a−1 in Eastern Pamir, with considerable temporal and spatial variability. Highest rates of mass loss occurred in Central Himalaya and Northern Tien Shan after 2015 and even in regions where glaciers were previously in balance with climate, such as Eastern Pamir, mass losses prevailed in recent years. An increase in summer temperature explains the long-term trend in mass loss and now appears to drive mass loss even in regions formerly sensitive to both temperature and precipitation.

Age, chemistry, and tectonic setting of Miramichi terrane (Early Paleozoic) volcanic rocks, eastern and east-central Maine, USA

2021 ◽  
Vol 57 ◽  
pp. 239-273
Author(s):  
Allan Ludman ◽  
Christopher McFarlane ◽  
Amber T.H. Whittaker
Keyword(s):  
New Brunswick ◽  
Subduction Zone ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Calc Alkaline ◽  
East Central ◽  
Arc Volcanism ◽  
Middle Ordovician ◽  
Volcanic Suite ◽  
Back Arc

Volcanic rocks in the Miramichi inlier in Maine occur in two areas separated by the Bottle Lake plutonic complex: the Danforth segment (Stetson Mountain Formation) north of the complex and Greenfield segment to the south (Olamon Stream Formation). Both suites are dominantly pyroclastic, with abundant andesite, dacite, and rhyolite tuffs and subordinate lavas, breccias, and agglomerates. Rare basaltic tuffs and a small area of basaltic tuffs, agglomerates, and lavas are restricted to the Greenfield segment. U–Pb zircon geochronology dates Greenfield segment volcanism at ca. 469 Ma, the Floian–Dapingian boundary between the Lower and Middle Ordovician. Chemical analyses reveal a calc-alkaline suite erupted in a continental volcanic arc, either the Meductic or earliest Balmoral phase of Popelogan arc activity. The Maine Miramichi volcanic rocks are most likely correlative with the Meductic Group volcanic suite in west-central New Brunswick. Orogen-parallel lithologic and chemical variations from New Brunswick to east-central Maine may result from eruptions at different volcanic centers. The bimodal Poplar Mountain volcanic suite at the Maine–New Brunswick border is 10–20 myr younger than the Miramichi volcanic rocks and more likely an early phase of back-arc basin rifting than a late-stage Meductic phase event. Coeval calc-alkaline arc volcanism in the Miramichi, Weeksboro–Lunksoos Lake, and Munsungun Cambrian–Ordovician inliers in Maine is not consistent with tectonic models involving northwestward migration of arc volcanism. This >150 km span cannot be explained by a single east-facing subduction zone, suggesting more than one subduction zone/arc complex in the region.

scholarly journals Geothermometry of Northern Tien Shan Thermal Waters (Issik-Kul Lake Basin)

2020 ◽  
Author(s):  
George Chelnokov ◽  
Vasily Lavrushin ◽  
Ivan Bragin ◽  
Abdulaziz Abdullaev ◽  
Natalia Kharitonova
Keyword(s):  
Tien Shan ◽  
Thermal Waters ◽  
Lake Basin ◽  
Northern Tien Shan

Empirical relationship between particulate matter and aerosol optical depth over Northern Tien-Shan, Central Asia

2012 ◽  
Vol 6 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Boris B. Chen ◽  
Leonid G. Sverdlik ◽  
Sanjar A. Imashev ◽  
Paul A. Solomon ◽  
Jeffrey Lantz ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Central Asia ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Empirical Relationship ◽  
Tien Shan ◽  
Northern Tien Shan
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