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Variability of orographic architecture of Indo-Burmese Ranges (NE India) : constraints from morphotectonic and lineament analysis

Rakshit Raghupratim, Bezbaruah Devojit, Zaman Farha, Bharali Bubul

Geological Quarterly

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2020

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Vol. 64, No. 1

130--140

EN

Activeness of the tectonic and related sub-surface processes control the surface features that lead to variations in topography and lithostratigraphy. To understand the role of active tectonis in shaping the topography, morphotectonic and lineament studies are important. In this study, geological categorization has helped understand the orogenic evolution of the Indo-Burmese Range (IBR), NE India. This is an arcuate hill range that shows many unique topographic characteristics that incited to categorise the entire IBR into different tectonically active domains: Northern (Changlang district of Arunachal Pradesh); Naga Hills; Cachar and Manipur; and Southern (Mizoram). The Northern and Southern domains are more active than the others. Lineament analysis also indicates the presence of active features in the region with NW-SE, NE-SW, ESE-WNW trends are being common. The Northern and Naga Hills domains have mostly E-W younger lineaments whereas the Cachar and Manipur domains rather show N-S younger trends. The Southern Mizoram domain shows a dominance of older N-S lineaments with younger NW-SE lineaments. These variations result from differential stress conditions, i.e. Indian Plate movement and westward stress from the Burma Plate. This study shows how overall variations in tectonic settings can be related to the orogenic evolution.

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Deformation analysis in central west Bulgaria using triangulation and GPS data

Dimitrov Nikolay

Reports on Geodesy and Geoinformatics

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2019

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Vol. 108

23--26

EN

The article discusses a method applied for combining the results of Global Navigation Satellite Systems (GNSS) and 75-year old triangulation measurements to estimate the crustal movements in central western Bulgaria region. It was examined for joint analysis based on the results of GNSS with angular measurements of the first order triangulation network in Bulgaria during the period 1923–1930 year. As a result of the processing of GNSS and angular measurements, horizontal velocities of 15 points, strain rates, and rotation rates have been obtained. The results show dominating N–S extension at a rate of 1–2 mm/y and the deformation is not uniformly distributed over the studied area. The obtained results indicate the possibility of using old angular measurement of first-order triangulation points, together with GNSS data, to obtain estimates of the horizontal crustal movements.

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Employing Minimum age model (MAM) and Finite mixture modeling (FMM) for OSL age determination of two important samples from Ira Trench of North Tehran Fault

Fattahi M., Heidary M., Ghasemi M.

Geochronometria

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2016

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Vol. 43, no. 1

38--47

EN

Ira trench site is in a point where, the surface trace of North Tehran Fault (NTF) joins the Mosha Fault (MF) in the north-eastern margin of Tehran and can provide important paleosismological information for Tehran. The Ira trench, were divided into 6 packages (I to VI), described, according to their composition, relative and absolute ages. Package I consists of units 23, 25, 26, 27, 28, 29, 30 and 31. The whole package I mainly belongs to Holocene, and provides essential constraints for the recent paleo-earthquake activity of the EMF and NTF zone. Therefore, finding accurate ages for the units of this package is very important. Three colluvial wedges (units 23, 26, 28) are present between 20 and 36.5 m north in package I, which are assigned to 3 episodes of activity on Fault 13. Central age model (CAM) provided OSL ages of 35.0 ± 6.1, 7.3 ± 1.3, 6.4 ± 0.9 and 56 ± 6.5 ka for units 23, 26, 28 and 29, respectively. The conflicting ages of 56 ± 6.5 and 35.0 ± 6.1 ka (for units 23 and 29, respectively) as compared to the underlying younger units suggest that these ages are overestimated. MAM provided OSL ages of 13.1 ± 4.3 and 3.5 ± 0.4 ka for units 23 and 29, respectively. The contribution of the new statistical age model of sample IRA4 to the paleoseismic data is discussed.

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Present-day Horizontal Mobility in the Serbian Part of the Pannonian Basin; Inferences from the Geometric Analysis of Deformations

Susić Z., Toljić M., Bulatović V., Ninkov T., Stojadinović U.

Acta Geophysica

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2016

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Vol. 64, no. 5

1626--1654

EN

In tectonically complex environments, such as the Pannonian Basin surrounded by the Alps–Dinarides and Carpathians orogens, monitoring of recent deformations represents very challenging matter. Efficient quantification of active continental deformations demands the use of a multidisciplinary approach, including neotectonic, seismotectonic and geodetic methods. The present-day tectonic mobility in the Pannonian Basin is predominantly controlled by the northward movement of the Adria micro-plate, which has produced compressional stresses that were party accommodated by the Alps-Dinarides thrust belt and partly transferred towards its hinterland. Influence of thus induced stresses on the recent strain field, deformations and tectonic mobility in the southern segment of the Pannonian Basin has been investigated using GPS measurements of the horizontal mobility in the Vojvodina area (northern Serbia).

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Identification of tectonically active areas using DEM : a quantitative morphometric analysis of Mt. Medvednica, NW Croatia

Matoš B., Tomljenović B., Trenc N.

Geological Quarterly

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2014

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Vol. 58, No. 1

51--70

EN

Mt. Medvednica is an inselberg in NW Croatia which tectonically lies at the intersection between Southeastern Alps, Northwestern Dinarides and Tisza Mega-Unit of the Pannonian basin. Due to the Pliocene-Quaternary N-S directed transpression it experienced a differential uplift between 1500-2000 m and exposes pre-Neogene and Neogene tectonic and stratigraphic units surrounded by Pliocene-Quaternary sediments. This paper evaluates a set of methods in quantitative morphometry, used here for identification of tectonically active areas within a region characterized by low-rate active folding and faulting during the Pliocene-Quaternary times. Analysis employed extraction of hypsometric curves, calculation of hypsometric integral, asymmetry factor, and statistical parameters of normalized longitudinal main stream profiles of 36 drainage basins delineated from a 25-m resolution DEM of Mt. Medvednica area. Despite lithological heterogeneity, obtained morphometric parameters are considered as fairly good indicators for discriminating tectonically active from inactive areas. Based on calculated parameters, in combination with geological data, the most tectonically active areas during the Quaternary are found at the SW corner of the Mt. Medvednica related to an active segment of the North Medvednica Boundary Fault, and in the central part of the mountain related to the Kašina fault zone subdividing mountain into the NE and SW units.

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Tectonic control of tufa occurrences in the Podhale Synclinorium (Central Western Carpathians, southern Poland)

Mastella L., Rybak-Ostrowska B.

Geological Quarterly

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2012

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Vol. 56, No. 4

733–-744

EN

Tufas in the Podhale Synclinorium (southern Poland) occur as encrustations on moss and plant remains, crusts, porous, clastic and massive tufas. The tufas are almost entirely composed of calcite with small admixture of quartz, illite and chlorite. These deposits indicate the biotic and/or abiotic origin of calcium carbonate. The tufas occur in the vicinity of map-scale and minor fault zones. They precipitate near fissure springs linked with small faults and fault rocks or seepages along them. Exposures with tufas occur along several oblique and lateral zones. The oblique zones are related to Białka and Biały Dunajec faults that have normal components. The lateral zones of tufa occurrences are connected with lateral faults limiting the “zone of beds with gentle dips” and extensional brittle structures within the hinge of the synclinorium. The relationship of the tufa with brittle extensional structures suggests Quaternary tectonic activity of the Podhale Synclinorium that can be explained by continued uplift in the area studied.