Wyniki wyszukiwania - BazTech

1

Tectonic geomorphology and neotectonic setting of the seismically active South Wagad Fault (SWF), Western India, using field and GPR data

Maurya D. C., Chowksey V., Tiwari P., Chamyal L. S.

Acta Geophysica

|

2017

|

Vol. 65, no. 6

1167--1184

EN

The South Wagad Fault (SWF) is an E–W trending fault that delimits the Wagad uplift comprising Mesozoic rocks in its northern upthrown block and Neogene–Quaternary sediments in the southern downthrown block. Detailed GPR investigations were carried out at seven sites selected after field studies. All profiles clearly showed the lithological contrast across the fault. The sharp amplitude contrast of the radar waves along a vertical to sub-vertical line is interpreted as the near surface trace of the SWF. As the Quaternary sediments are not displaced, we infer that no large magnitude earthquake has occurred along the SWF in late Quaternary. We attribute the low magnitude of neotectonic activity along the SWF to gentle warping of the Tertiary rocks in the southern downthrown block and greater accumulation of compressive stresses along the nearby KMF with an opposite structural setting. This is consistent with the observed variable levels of ongoing seismicity in the region around the SWF.

2

Wskaźniki morfometryczne w geomorfologii tektonicznej

Różycka M.

Landform Analysis

|

2015

|

Vol. 30

3--20

PL

Geomorfologia tektoniczna jest dynamicznie rozwijającą się dziedziną nauki – głównie za sprawą nowych możliwości badawczych, które pojawiły się wraz z rozwojem narzędzi udostępnianych za pośrednictwem Geograficznych Systemów Informacyjnych (GIS) oraz z wprowadzeniem cyfrowych zestawów danych wysokościowych. Dzięki temu rozwijany jest przede wszystkim ilościowy kierunek tych badań. Niniejsza praca ma charakter przeglądowy. Zestawiono w niej, podzielono oraz omówiono wskaźniki morfometryczne wykorzystywane w badaniach nad młodą aktywnością tektoniczną obszarów, zwracając jednocześnie uwagę na ograniczenia interpretacyjne związane z ich wykorzystywaniem. Przegląd literatury uwzględnia opracowania zarówno polskie, jak i zagraniczne opublikowane w latach 2000–2015.

EN

New research possibilities that emerged from the development of Geographic Information Systems (GIS) and digital topography underpin the growth of tectonic geomorphology, mainly in respect to quantitatively oriented investigations. This paper presents a review of morphometric parameters that have been applied in morphotectonic studies in Poland and worldwide and is essentially based on papers published from 2000 to 2015. Classification of tectonic activity indicators is presented, as well as limitations in their interpretation are discussed.

3

Late cenozoic tectonic activity of The Śnieżnik Massif area (the Sudetes, SW Poland) in the light of LiDAR DEM morphometric analysis

Sobczyk A., Kasprzak M.

Studia Geomorphologica Carpatho-Balcanica

|

2014

|

Vol. 48

35--52

EN

The Śnieżnik Massif represents a prominent morphological feature in the East Sudetes, which is bounded by a system of faults controlling its differential uplift. Vertical movements originated at least during the Oligocene times, with culmination phase in the Pliocene times, whereas estimated total uplift was in the range of 500–1000 meters. This study presents a qualitative (geomorphometric) and quantitative (morphotectonic) approach that combines the Late Cenozoic tectonic uplift model with landscape evolution theories. Application of basin asymmetry factor (AF) and hypsometric integral (Hi) analyses allowed recognizing a NW trending, presumably tilted, fault blocks. They originated as a result of the Palaeogene planation surface braking and differential uplift. Uplift and later fault-block tilting in the Śnieżnik Massif morphotectonic unit, were generally realized along NE-SW striking the Wilkanów fault to the west and WNW-ESE striking southern fault zone, as expressed here e.g. by Potoczek-Branna, Hermanice and Pisary faults.

4

Quaternary evolution of a Carpathian Foothills area: An example from the East Carpathians of Poland

Zuchiewicz W., Zasadni J.

Annales Societatis Geologorum Poloniae

|

2010

|

Vol. 80, No 3

327-345

EN

The East Carpathian Foothills of Poland witnessed two episodes of relief planation in the Pliocene, followed by formation of Early Pleistocene strath terraces preserved on flat-topped meander spurs in the San River valley at altitudes of 100-120 m above recent floodplains. In the following stages, intense erosion produced of a flight of strath terraces that are provisionally dated to the Narevian or Sanian-1 (Menapian or Elsterian-1; 75-80 m), Sanian-2 (Elsterian-2; 40-60 m), Odranian and Wartanian (Drenthe, Warthe; 20-30 m), and Vistulian (Weichse- lian; 8-16 m) times. During glacial stages, solifluction deposits mantled the feet of gentle slopes being coeval with fluvial deposition and accumulation of loesses and loess-like sediments on either side of the San River valley, particularly intense in the Weichselian. Interglacial warmings fostered downcutting of the pre-existing fluvial sediments as well as formation of fossil soils within loess sequences and deposition of peat in abandoned channels. In the Late Pleistocene and at the beginning of the Holocene, diversified tectonic movements took place leading to displacement of Weichselian and Holocene straths. During the Holocene, in turn, cut-and-fill terrace steps were shaped, organogenic sediments filled abandoned channels and oxbow lakes, and slopes became re-modelled by landslides and slopewash. The pattern of different types of relief, together with spatial distribution of topolineaments and some photolineaments in the eastern portion of the Polish Outer Carpathians, has been shaped due to mutual interactions between climatic, lithologic and tectonic factors. Well-pronounced topolineaments either follow fault-related zones of weakness, are associated with dense network of extensional cross-fold joints, or indicate recent reactiva-tion of some faults and/or joint sets.

5

Steep slopes in the Sudetes and their morphotectonic interpretation

Migoń P., Placek A., Żyszkowska W.

Geological Quarterly

|

2009

|

Vol. 53, No 2

219-232

EN

The Sudetes is a block-faulted mountain range in Central Europe, at the NE margin of the Bohemian Massif. In the late Cenozoic it has been subject to differen ial up lift and subsidence and currently represents a horst-and-graben structure, superimposed on older relief due to rock-controlled denudation and erosion. In this paper, the distribution of steep slopes (>15grade and >25grade) is analyzed using a Digital Elevation Model (DEM) of 50 m spatial resolution, and their morphotectonic significance is discussed. Steep slopes occur in four major settings: heavily dissected and most elevated highlands, straight mountain fronts, narrow sinuous escarpments, and deeply incisedriver valleys. The former in particular may indicate areas subject to recent uplift, which is followed by efficient fluvial incision, so that little pre-up lift topography has survived. The image of many mountain fronts on the slope map is rather poor, which may be explained by the mechanical weakness of the rock building the footwall. At the sametime, the association of the majority of tectonically-induced steep slopes with the most resistant rocks suggests that the intensity of recent uplift is generally low compared with the long-term rates of denudation and erosion.