scholarly journals Response of modern fluvial sediments to regional tectonic activity along the Min River in eastern Tibet

2021 ◽  
Author(s):  
Wei Shi ◽  
Hanchao Jiang ◽  
Siyuan Ma ◽  
Hongyan Xu ◽  
Jiawei Fan ◽  
...  
Keyword(s):  
Tectonic Activity ◽  
Fluvial Sediments ◽  
Min River ◽  
Eastern Tibet ◽  
Regional Tectonic

scholarly journals ESR geochronology of the Minjiang River terraces at Wenchuan, eastern margin of Tibetan Plateau, China

2013 ◽  
Vol 40 (4) ◽  
pp. 360-367 ◽  
Author(s):  
Chun-Ru Liu ◽  
Gong-Ming Yin ◽  
Hui-Ping Zhang ◽  
Wen-Jun Zheng ◽  
Pierre Voinchet ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tectonic Activity ◽  
The Tibetan Plateau ◽  
Fluvial Sediments ◽  
River Terrace ◽  
Eastern Margin ◽  
River Terraces ◽  
Quaternary Climate ◽  
Minjiang River ◽  
Longmen Shan Fault

Abstract The Minjiang River terrace along the Longmen Shan fault zone near Wenchuan, at the eastern margin of the Tibetan Plateau, China, provides archives for tectonic activity and quaternary climate change. However, previous studies were not able to provide ages older than 100 ka due to the limitations of dating material or/and methods applied to date the fluvial sediments. In this study, we used the ESR signal of the Ti-Li center in quartz to obtain the ages of four higher terraces (T3–T6). According to the results, the terraces T3 to T6 were formed at 64±19 ka, 101±15 ka, 153±33 ka, and 423±115 ka, respectively. Combined with previous studies, these results indicate that the formations of all terraces correspond to glacial/interglacial transition periods, such as, T1-T5 being correlated to MIS2/1, MIS4/3, MIS5d/5c, and MIS6/5e respectively, while T6 probably to MIS12/11. According to these data, it is found that the average incision rate was significantly higher over the last 150 ka than that previous 100 ka (250 to 150 ka). As both tectonics and climate have affected the formation of these terraces, in addition to the overall uplifting of Tibetan Plateau, the regional uplift due to isostasy would be an additional tectonic factor in the formation of river terraces in the eastern margin of Tibetan plateau.

scholarly journals Petrogenesis of Volcanic Arc Granites from Bayah Complex, Banten, Indonesia

2019 ◽  
Vol 4 (2) ◽  
pp. 104
Author(s):  
Jemi Saputra Ahnaf ◽  
Aton Patonah ◽  
Haryadi Permana
Keyword(s):  
Tectonic Setting ◽  
Crustal Contamination ◽  
Polarized Light ◽  
Granitic Rocks ◽  
Tectonic Activity ◽  
Molar Ratio ◽  
Petrographic Analysis ◽  
Volcanic Arc ◽  
Regional Tectonic ◽  
Type Granite

This research aimed to reveal the petrogenesis of granitic rocks of Bayah Complex starting from magma differentiation to exposing event, this research also intended to determine the tectonic environment. The methods carried out in this research include field observation, petrographic analysis using polarized light microscopy, and geochemical analysis using X-Ray Fluorescence (XRF) and Inductively Coupled Mass Spectrometry (ICP-MS). Petrographic analysis shows that Bayah granitic rocks are composed of quartz, plagioclase, and K-feldspar while the rest are amphibole, biotite, sericite, chlorite, epidote, and opaque. Based on its major oxide concentrations, Bayah granitic rocks classified as granite and diorite-quartz which have high-K calc-alkaline magma. 4 samples of granitic rocks showed the A/N+K+C > 1 molar ratios belonging to the peraluminous S-type granite index while the remaining 1 sample showed a molar ratio of A/N+ K+C < 1 and A/N+K > 1 which classified as metaluminous I-type granite. Accordingly, Bayah granitic rocks are S-type granite which crystallized from sediment-derived magma, the sediments itself estimated sourced from continental especially Malay Peninsula, Indonesian Tin Island, and Schwaner Mountains. During differentiation, the magma undergone crustal contamination reflected by the increase in both SiO2 0.51 wt% and Al2O3 1.95 wt%, and decrease in Fe2O3 + MgO 0.61 wt% from the pure composition of sediment-derived magma. Furthermore, the occurrence of crustal contamination also recognized from high concentrations of Rb and Ba which indicate the interaction of magma with the materials of continental crust. Regard to the exposing event, Bayah granitic rocks approximated to be exposed due to regional tectonic activity which caused Orogenesa I in the Early Oligocene to the Late Oligocene. Moreover, based on the plot of trace elements especially Rb, Y, Nb, Ta, and Yb on Harker and tectonic discriminant diagrams, Bayah granitic rocks are formed on volcanic-arc active continental margins in accordance with regional tectonic setting.           

scholarly journals WATERSHED TOPOGRAPHIC CHARACTERISTICS AND CAUSES ANALYSIS OF THE UPPER REACHES OF THE WEIHE RIVER

2020 ◽  
Vol XLII-3/W10 ◽  
pp. 471-477
Author(s):  
Z. H. Liu ◽  
L. Han ◽  
T. T. Wu ◽  
C. Y. Du ◽  
N. Cao
Keyword(s):  
Transitional Period ◽  
Tectonic Activity ◽  
Surface Erosion ◽  
Mean Values ◽  
Hypsometric Integral ◽  
Basin Topography ◽  
Regional Tectonic ◽  
Weihe River ◽  
Topographic Characteristics ◽  
The Mean

Abstract. The morphology of watershed is the most intuitive information carrier to reflect regional tectonic activity, surface erosion and morphologic evolution. Active tectonic and fluvial system play a significant role in patterns and characters of regional morphology. Taking twenty-nine tributaries of the upper reaches of the Weihe River as the main study objects, four parameters, such as gully density (GD), basin topography ratio (BTR), roundness ratio (RR), river longitudinal profile fitting exponent (RLPFE), etc., were used to quantitatively analyse the topographic characteristics in this area. To reveal the main cause of the characteristics, the hypsometric integral (HI) were also applied in this area. The results showed that: (1) There is a positive linear function between basin topography ratio (BTR) and mean slope, and the mean values of four indexes in northern channels are smaller than southern channels; (2) The mean HI value is 0.44, indicating that the main topographic characteristics of this area is in maturity, which is in the transitional period of adjustment of the deep erosion and uplift movement; (3) The main cause of this topographic changes is tectonic. These results are consistent with other geological background, and will enrich regional basin morphology research and tectonic activity evaluation, provide important basic data for regional disaster prediction and analysis of soil and water loss.

scholarly journals Quasi real-time electromagnetic and greenhouse gases monitoring station at Seymour - Marambio Island, Antarctica

2021 ◽  
Vol 11 (1) ◽  
pp. 1-8
Author(s):  
Juan Manuel Solano ◽  
Carlos Alberto Vargas ◽  
Adriana Maria Gulisano
Keyword(s):  
Greenhouse Gases ◽  
Real Time ◽  
Time Synchronization ◽  
Global Climate ◽  
Low Cost ◽  
Low Noise ◽  
Tectonic Activity ◽  
Regional Tectonic ◽  
Electromagnetic Signals ◽  
Carbon Dioxide Co2

A new permanent geophysical station was installed in the Seymour-Marambio Island, Antarctica, for monitoring electromagnetic, CO2, and CH4 gas signals. Those signals require specialized low noise instruments and the survey shall be carried out in places far away from cultural noise, such as populated human settlements. The most suitable place would be near the Earth's poles, where noise is the lowest possible. To measure these variables, the Geophysical Instrumentation Laboratory (Laboratorio de Instrumentación Geofísica - LIG) of the Universidad Nacional de Colombia, in a partnership with the Instituto Antártico Argentino (IAA) under the Argentinean National Antarctic Direction (Dirección Nacional del Antártico - DNA), deployed the COCOAonMEAT project, oriented to design, built and install a low-cost station with time synchronization via GPS and data transmission in almost real-time. Since January 2020, the project monitors continuously (24/7) seven variables: three magnetic components, two electric dipoles, methane (CH4), and carbon dioxide (CO2) gas. Due to operative facilities and its low electromagnetic noise, the place chosen for its installation was the Argentinean Marambio Scientific Base in the Antarctic Peninsula, with the Multidisciplinary Antarctic Laboratory's collaboration (Laboratorio Multidisciplinario Antártico en la Base Marambio - LAMBI). This station provides valuable information on electromagnetic signals and greenhouse gases related to regional tectonic activity and local perturbations associated with global climate change.

scholarly journals Application of observations of recent tectonic activity in the Świebodzice Depression (the Sudetes, SW Poland) in assessing seismic hazard in the Fore-Sudetic Monocline

2018 ◽  
Vol 55 ◽  
pp. 00001 ◽  
Author(s):  
Marek Kaczorowski ◽  
Damian Kasza ◽  
Ryszard Zdunek ◽  
Roman Wronowski
Keyword(s):  
Vertical Movement ◽  
Rock Massif ◽  
Fault System ◽  
Tectonic Activity ◽  
Regional Tectonic ◽  
Sw Poland ◽  
Tidal Signal ◽  
Representative Function ◽  
Low Activity

Tiltmeter observations with application of horizontal pendulums have been carried out for 40 years in the Geodynamic Laboratory in Książ. Long-term observations have not indicated any correlation of these data with meteorological or seasonal phenomena. Following an epoch of fast azimuth changes, a gradual compensation process took place, excluding the effect of gravitational creep of the rock massif. An assumption was made that the observed large changes of the equilibrium azimuths of the horizontal pendulums that result from tectonic tilt of the foundation blocks. Multiannual tiltmeter observations allowed to determine the temporal characteristics and amplitude tectonic effects. Intervals of strong tectonic activity in the rock massif of the Świebodzice Depression last from several days to over ten weeks and are separated by several tens of hours of low activity. Amplitude of the rock massif deformation reaches values from over ten to several tens of amplitudes of the tidal signal, i.e. up to several hundreds of micrometres. Water-tube tiltmeters (WT) launched in 2003 have confirmed the characteristics of tectonic effects and their incidental occurrence. Beside the tilt effects, WT have enabled to confirm vertical movement of the foundation blocks. Geological investigations in the Świebodzice Depression have indicated the presence of a numerous faults separating particular blocks in the rock massif. The presence of this fault system favours the dislocation of foundation blocks, which results in a quake-less relaxation of tectonic stresses and absence lack of seismic activity in the Świebodzice Depression. Foundation blocks separated by faults combined with the multiscale measurement system of WTs form a natural detector of regional tectonic activity, allowing to determine with micrometric resolution the representative function of tectonic activity in the rock massif of the Świebodzice Depression.

scholarly journals Quaternary tectonic and depositional evolution of eastern Srem (northwest Serbia)

2014 ◽  
pp. 43-57 ◽  
Author(s):  
Marinko Toljic ◽  
Drazenko Nenadic ◽  
Uros Stojadinovic ◽  
Tivadar Gaudenyi ◽  
Katarina Bogicevic
Keyword(s):  
Stress Field ◽  
Compressive Stress ◽  
Cross Sections ◽  
Pannonian Basin ◽  
Tectonic Activity ◽  
Late Neogene ◽  
Genetic Features ◽  
Regional Tectonic ◽  
Depositional Evolution ◽  
Structural Plan

The area of eastern Srem is situated in the southern periphery of the Pannonian basin. Its depositional evolution during the Neogene and the Quaternary has been controlled by tectonic processes. Miocene extensional subsidence was followed by the Pliocene-Quaternary inversion of the basin. The latter was accomplished as the result of replacement of the tensile by the compressive stress field. Since the Late Neogene, the regional tectonic activity has been controlled by compressive stress produced by the northnortheastern propagation of the Adria microplate. In the compressive NE-SW-oriented stress field, the recent structural plan of the Pannonian basin and its wider environment, including its southern periphery, was reactivated. The youngest tectonic deformations are characterized by positive and negative vertical motions of large intrabasinal segments and basinal periphery, resulting in the final inversion of the basin. The effects of the basinal inversion can be recognized in genetic features of Quaternary sediments and geomorphological characteristics of the relief. Sources of data used for the interpretation of the Quaternary tectonic activity in the area of eastern Srem are of geological, geomorphological, thermochronological, and geophysical character. The positions of prominent fault structures have been ascertained by remote sensing, interpretations of available geophysical cross-sections, and using the field data.

Analysing landforms, borehole logs, and geophysics, for localization and assessment of active faults in the central Vienna Basin (Austria)

2020 ◽  
Author(s):  
Michael Weissl ◽  
Decker Kurt ◽  
Adrian Flores-Orozco ◽  
Matthias Steiner
Keyword(s):  
Active Faults ◽  
Fault System ◽  
Tectonic Activity ◽  
Fluvial Sediments ◽  
River Channels ◽  
Vienna Basin ◽  
Geothermal Resources ◽  
Near Surface ◽  
Growth Strata ◽  
Fault Scarps

&lt;p&gt;The formation of pull apart basins and normal faulting at splays along the Vienna Basin strike-slip fault system resulted in the dissection of the Pleistocene river terraces of the Danube. Displacements of terrace segments are visible on the surface as fault scarps or dells what allows mapping the system of active faults. Furthermore displacement rates can be estimated from the elevation of the basis and the thickness of Quaternary fluvial sediments.&lt;/p&gt;&lt;p&gt;With regard to the prospective utilization of geothermal resources in the area of Vienna a research group was built (Geotief Explore 3D, funded by Wien Energie and FFG) with the objective to identify, map, and assess, Quaternary faults, because such rupture zones are not suitable for the reinjection of thermal water in view of the hazard of triggered earthquakes.&lt;/p&gt;&lt;p&gt;Normal splay faults define the eastern and western margins of Pleistocene Danube terraces north of Vienna. The bodies of these terraces are built up of coarse sandy gravel and sand whereas their surfaces are covered with aeolian and alluvial sediments of the last glacial. Tectonic displacements during the Pleistocene left distinct marks in the late glacial landform configuration of the terraces. Therefore many fault scarps and fault related valleys are clearly cognizable in high resolution LiDAR and satellite images.&lt;/p&gt;&lt;p&gt;During the last decade three distinct fault scarps of the Vienna Basin Transform Fault situated at the terrace edges could be investigated by trenching and transect analysis. Actual research has the objective to model the 3D geometry of the base of the Quaternary strata (horizon Base Quaternary) from a compilation of shallow drillings and the construction of a regional isopach map showing the thickness of Quaternary (growth-) strata.&lt;/p&gt;&lt;p&gt;In the course of research it becomes apparent that within the tectonically subsided areas evidence of neotectonics is overprinted by fluvial sediments and alluvium what hinders accurate localization of faults. However, the sinuosity of palaeochannels in the Danube floodplain seems to be related to tectonics and therefore the pattern of former river channels can be used as sign for tectonic activity during the Pleistocene. In places where signs for active faulting are completely overprinted by fluvial sedimentation and cryoturbation the approved methods for the localization and the assessment of active faults are electrical resistivity tomography and near-surface seismics.&lt;/p&gt;

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