An investigation approach of the volcanic geomorphology in the Călimani – Gurghiu – Harghita volcanic chain, Romania

2021 ◽  
Author(s):  
Viorel Marian Mirea ◽  
Alexandru Szakács ◽  
Ioan Seghedi
Keyword(s):  
Vegetation Cover ◽  
Sedimentary Basins ◽  
3D Models ◽  
Debris Avalanche ◽  
Geological Mapping ◽  
Terrain Analysis ◽  
Main Challenge ◽  
Volcanic Chain ◽  
Volcanic Facies ◽  
Srtm Data

<p><span><span>In poorly-exposed forest-covered volcanic areas, the main challenge in classical geological and geomorphological studies is the interpretations of landforms and volcanic structures. The usage of 3D models provides modern opportunities in visualization of volcanic landforms in volcanological studies in areas with dense vegetation cover</span></span><span><span>. </span></span></p><p><span><span>Geological mapping of the Neogene Călimani-Gurghiu-Harghita (CGH) volcanic chain is challenging due poor exposure of area. The Călimani-Gurghiu-Harghita volcanic chain exhibits ~10 My age range spanning from North (> 10 Ma) to South (< 0.03 Ma) linked to the evolution of the adjacent intra-mountain sedimentary basins (</span></span><span>Bilbor, Borsec, Gheorgheni, Upper Ciuc, Lower Ciuc, Brașov </span><span><span>and </span></span><span>Baraolt </span><span><span>basins</span></span><span>)</span><span><span>. The geomorphological analysis of the CGH volcanic chain is currently performed using SRTM data. However, the SRTM data are affected by the vegetation cover. Instead, we used a digital elevation models (DEM) built from topographic maps in combinations with volcanological field observations.</span></span></p><p><span>Our method uses a DEM 3D spatial view with overlay standard geological maps, shaded relief complemented with terrain analysis and landform recognition. Then, the study integrates field-based observations and geomorphological mapping results in a new general overview of the complex volcanic topography of the CGH volcanic chain. </span></p><p><span><span>Using </span></span><span><span>digital</span></span><span><span> elevation models (DEM) allows the general identification of volcanic facies distribution (proximal, medial and distal) belonging to </span></span><span><span>an individual</span></span><span><span> volcanic structures as well as the regional assemblages of the whole volcanic chain. DEM studies also permit to reconstruct the erosion level of volcanic edifices in conjunctions with field-based volcanological studies. This approach may also help identifying volcanological formations and various types of volcanic facies resulting from both construction and destructions of the edifices in poorly exposed areas.</span></span></p><p><span><span>By using this methodology a broad range of volcanic morphological features have been observed along the CGH volcanic range including the </span></span><span>Călimani</span><span><span> caldera morphology, features of the old and young debris avalanche deposits of various volcanic edifices and the youngest lava-dome morphology of </span></span><span>Ciomadul</span><span><span> volcano. Our DEM approach provides better results than those obtained by previous studies pointing out, for instance, that the volcanic edifices are highly to moderately eroded in the north and progressively better preserved toward the south. </span></span></p><p><span>Acknowledgements. The research was funded through CNCS – UEFISCDI, project number PN-III-P4-ID-PCCF-2016-4-0014, within PNCDI III.</span></p>

scholarly journals Wandering continents of the Indian Ocean

2019 ◽  
Vol 122 (4) ◽  
pp. 397-420 ◽  
Author(s):  
L.D. Ashwal
Keyword(s):  
Indian Ocean ◽  
News Media ◽  
Sedimentary Basins ◽  
Geological Mapping ◽  
Gravity Inversion ◽  
General Outline ◽  
Research Activities ◽  
The Indian Ocean ◽  
Andean Type ◽  
Break Up

Abstract On the last page of his 1937 book “Our Wandering Continents” Alex Du Toit advised the geological community to develop the field of “comparative geology”, which he defined as “the study of continental fragments”. This is precisely the theme of this paper, which outlines my research activities for the past 28 years, on the continental fragments of the Indian Ocean. In the early 1990s, my colleagues and I were working in Madagascar, and we recognized the need to appreciate the excellent geological mapping (pioneered in the 1950s by Henri Besairie) in a more modern geodynamic context, by applying new ideas and analytical techniques, to a large and understudied piece of continental crust. One result of this work was the identification of a 700 to 800 Ma belt of plutons and volcanic equivalents, about 450 km long, which we suggested might represent an Andean-type arc, produced by Neoproterozoic subduction. We wondered if similar examples of this magmatic belt might be present elsewhere, and we began working in the Seychelles, where late Precambrian granites are exposed on about 40 of the >100 islands in the archipelago. Based on our new petrological, geochemical and geochronological measurements, we built a case that these ~750 Ma rocks also represent an Andean-type arc, coeval with and equivalent to the one present in Madagascar. By using similar types of approaches, we tracked this arc even further, into the Malani Igneous Province of Rajasthan, in northwest India. Our paleomagnetic data place these three entities adjacent to each other at ~750 Ma, and were positioned at the margins, rather than in the central parts of the Rodinia supercontinent, further supporting their formation in a subduction-related continental arc. A widespread view is that in the Neoproterozoic, Rodinia began to break apart, and the more familiar Gondwana supercontinent was assembled by Pan-African (~500 to 600 Ma) continental collisions, marked by the highly deformed and metamorphosed rocks of the East African Orogen. It was my mentor, Kevin Burke, who suggested that the present-day locations of Alkaline Rocks and Carbonatites (called “ARCs”) and their Deformed equivalents (called “DARCs”), might mark the outlines of two well-defined parts of the Wilson cycle. We can be confident that ARCs formed originally in intracontinental rift settings, and we postulated that DARCs represent suture zones, where vanished oceans have closed. We also found that the isotopic record of these events can be preserved in DARC minerals. In a nepheline syenite gneiss from Malawi, the U-Pb age of zircons is 730 Ma (marking the rifting of Rodinia), and that of monazites is 522 Ma (marking the collisional construction of Gondwana). A general outline of how and when Gondwana broke apart into the current configuration of continental entities, starting at about 165 Ma, has been known for some time, because this record is preserved in the magnetic properties of ocean-floor basalts, which can be precisely dated. A current topic of active research is the role that deep mantle plumes may have played in initiating, or assisting, continental fragmentation. I am part of a group of colleagues and students who are applying complementary datasets to understand how the Karoo (182 Ma), Etendeka (132 Ma), Marion (90 Ma) and Réunion (65 Ma) plumes influenced the break-up of Gondwana and the development of the Indian Ocean. Shortly after the impingement of the Karoo plume at 182 Ma, Gondwana fragmentation began as Madagascar + India + Antarctica separated from Africa, and drifted southward. Only after 90 Ma, when Madagascar was blanketed by lavas of the Marion plume, did India begin to rift, and rapidly drifted northward, assisted by the Marion and Deccan (65 Ma) plumes, eventually colliding with Asia to produce the Himalayas. It is interesting that a record of these plate kinematics is preserved in the large Permian – Eocene sedimentary basins of western Madagascar: transtensional pull-apart structures are dextral in Jurassic rocks (recording initial southward drift with respect to Africa), but change to sinistral in the Eocene, recording India’s northward drift. Our latest work has begun to reveal that small continental fragments are present in unexpected places. In the young (max. 9 Ma) plume-related, volcanic island of Mauritius, we found Precambrian zircons with ages between 660 and 3000 Ma, in beach sands and trachytic lavas. This can only mean that a fragment of ancient continent must exist beneath the young volcanoes there, and that the old zircons were picked up by ascending magmas on their way to surface eruption sites. We speculate, based on gravity inversion modelling, that continental fragments may also be present beneath the Nazareth, Saya de Malha and Chagos Banks, as well as the Maldives and Laccadives. These were once joined together in a microcontinent we called “Mauritia”, and became scattered across the Indian Ocean during Gondwana break-up, probably by mid-ocean ridge “jumps”. This work, widely reported in international news media, allows a more refined reconstruction of Gondwana, suggests that continental break-up is far more complex than previously perceived, and has important implications for regional geological correlations and exploration models. Our results, as interesting as they may be, are merely follow-ups that build upon the prescient and pioneering ideas of Alex Du Toit, whose legacy I appreciatively acknowledge.

Ore geological studies of the Citronen Fjord zinc deposit, North Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’

1997 ◽  
pp. 44-49
Author(s):  
Karsten Kragh ◽  
Sven Monrad Jensen ◽  
Henrik Fougt
Keyword(s):  
Sedimentary Basins ◽  
Geological Mapping ◽  
Zinc Deposit ◽  
East Greenland ◽  
The North ◽  
Diamond Drilling ◽  
Field Season ◽  
Research Councils ◽  
North Western ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Kragh, K., Monrad Jensen, S., & Fougt, H. (1997). Ore geological studies of the Citronen Fjord zinc deposit, North Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’. Geology of Greenland Survey Bulletin, 176, 44-49. https://doi.org/10.34194/ggub.v176.5060 _______________ The multidisciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). In the 1996 field season, ore geological studies continued on the shale-hosted Citronen Fjord zinc-lead prospect in North Greenland (Figs 1, 2). Platinova A/S discovered the deposit in 1993, and has subsequently explored the area by means of geological mapping, gravity surveys and diamond drilling. About 30 km of diamond drilling have been completed, and a resource of over 20 million tons of stratiform ore with 7% zinc and 1% lead has been estimated (Platinova A/S, 1996a, b). An additional fault-controlled, high-grade zinc-mineralised zonewas encountered in the north-western part of the ‘Discovery Zone’ in 1996 (Platinova A/S, 1996b).

scholarly journals Petrography, Geology Structure and Landslide Characterization of Sumatra Fault Deformation: Study Case In Km 10-15 Highway, Koto Baru Sub District, West of Sumatra

2018 ◽  
Vol 3 (4) ◽  
pp. 192 ◽  
Author(s):  
Catur Cahyaningsih ◽  
Puja Fransismik Crensonni ◽  
Yogi Aditia ◽  
Adi Suryadi ◽  
Yuniarti Yuskar ◽  
...  
Keyword(s):  
Debris Avalanche ◽  
Research Area ◽  
Geological Mapping ◽  
Geological Condition ◽  
Translational Landslide ◽  
West Sumatra ◽  
Fault Deformation ◽  
Study Case ◽  
Geological Analysis

Research area is around Tanjung Balik, Koto Baru Sub Base, Lima Puluh Kota District, West Sumatra Province. Located along the highway Km 10-15 Riau – West Sumatra and the coordinate around 00˚08'40 '' LU - 0˚11'20 '' N and 100˚45'20 '' BT - 100˚47'00 '' BT. The purpose of research to identify petrography, microstructure, types of landslides and the geological condition. The methods using polarization microscope, stereography, landslide identification survey and geological mapping. The result of study shows the petrography analysis of lithology of study area are classified into three types of rocks are Feldspathic Greywacke, Lithic Arenite, and Slate. Microstructures trending system show the foliation structure that is relatively Southeast-Northwest. Types of landslide which dominates in the research area are debris avalanche and translational landslide. Geological analysis show some of rock units are classified into two units: Sandstone Unit and Slate Unit. Sandstone Unit spread in the northern part of the study area, while Slate Unit spread in the southern part of the study area. The characteristics of these rocks showed Pematang Formation.

scholarly journals From photo-geology to 3D geological models. An open source approach

2016 ◽  
Author(s):  
Michele Santangelo ◽  
Ivan Marchesini ◽  
Francesco Mirabella ◽  
Francesco Bucci ◽  
Mauro Cardinali ◽  
...  
Keyword(s):  
Open Source ◽  
Central Italy ◽  
Three Dimensional ◽  
3D Models ◽  
Geological Mapping ◽  
Aerial Photographs ◽  
Preliminary Evaluation ◽  
Three Dimensional Modeling ◽  
Geological Models ◽  
Open Source Gis

Three-dimensional modeling of geological bodies is a useful tool for multiple applications. Such tasks are usually accomplished starting from field-collected data, which typically suffer from intrinsic limitations such as accessibility constraints and punctuality of data collected. In this work, we explore the reliability of photo-geological mapping from interpretation of aerial photographs in providing data useful to build up 3D geological models. The test was conducted in a 15 km2 in Umbria, central Italy. The three-steps open source GIS procedure that outputs 3D models from photo-geological data was developed using python in GRASS GIS environment and GNU-Linux OS. We maintain that this procedure can have potential broad applications in Earth Sciences, including geological and structural analyses, up to the preliminary evaluation of potential reservoirs.

Sedimentary basins on the east flank of the Antarctic Peninsula: proposed nomenclature

1992 ◽  
Vol 4 (4) ◽  
pp. 477-478 ◽  
Author(s):  
R.A. Del Valle ◽  
D.H. Elliot ◽  
D.I.M. Macdonald
Keyword(s):  
Antarctic Peninsula ◽  
Sedimentary Rock ◽  
Sedimentary Basins ◽  
Geological Mapping ◽  
Basin Evolution ◽  
Island Area ◽  
James Ross Island ◽  
The Antarctic ◽  
South Polar ◽  
Seymour Island

The first fossils from Antarctica were collected from Seymour Island in December 1892, during the voyage of the Jason under Captain C.A. Larsen. The Swedish South Polar Expedition of 1901–1903, led by Otto Nordenskjöld, proved that there were extensive deposits of fossiliferous Cretaceous and Tertiary sedimentary rock in the James Ross Island area. This was confirmed by later geological mapping (Bibby 1966). Subsequent investigations have led to the establishment of various lithostratigraphic schemes (e.g. Ineson et al. 1986), and interpretation of the sedimentary history in terms of basin evolution (Elliot 1988, Macdonald et al. 1988). Unfortunately, different names have been proposed for the depositional basin, with consequent confusion. The purpose of this note is to review previous usage and propose a new consistent nomenclature for the sedimentary basins east of the Antarctic Peninsula.

scholarly journals Virtual Reality in Cartography: Immersive 3D Visualization of the Arctic Clyde Inlet (Canada) Using Digital Elevation Models and Bathymetric Data

2019 ◽  
Vol 3 (1) ◽  
pp. 9 ◽  
Author(s):  
Mona Lütjens ◽  
Thomas Kersten ◽  
Boris Dorschel ◽  
Felix Tschirschwitz
Keyword(s):  
Virtual Reality ◽  
Large Scale ◽  
3D Visualization ◽  
Technological Development ◽  
3D Models ◽  
Frame Rate ◽  
The Arctic ◽  
Terrain Analysis ◽  
Bathymetric Data ◽  
Digital Elevation

Due to rapid technological development, virtual reality (VR) is becoming an accessible and important tool for many applications in science, industry, and economy. Being immersed in a 3D environment offers numerous advantages especially for the presentation of geographical data that is usually depicted in 2D maps or pseudo 3D models on the monitor screen. This study investigated advantages, limitations, and possible applications for immersive and intuitive 3D terrain visualizations in VR. Additionally, in view of ever-increasing data volumes, this study developed a workflow to present large scale terrain datasets in VR for current mid-end computers. The developed immersive VR application depicts the Arctic fjord Clyde Inlet in its 160 km × 80 km dimensions at 5 m spatial resolution. Techniques, such as level of detail algorithms, tiling, and level streaming, were applied to run the more than one gigabyte large dataset at an acceptable frame rate. The immersive VR application offered the possibility to explore the terrain with or without water surface by various modes of locomotion. Terrain textures could also be altered and measurements conducted to receive necessary information for further terrain analysis. The potential of VR was assessed in a user survey of persons from six different professions.

scholarly journals A Globally Significant Potential Megascale Geopark: The Eastern Australian Mantle Hotspot Interacting with a North-Migrating Heterogeneous Continental Plate Creating a Variety of Volcano Types, Magmas, Xenoliths, and Xenocrysts

2021 ◽  
Author(s):  
Vic Semeniuk ◽  
Margaret Brocx
Keyword(s):  
Sedimentary Basins ◽  
Eurasian Plate ◽  
Volcanic System ◽  
Compositional Evolution ◽  
Continental Plate ◽  
Volcanic Chain ◽  
Eastern Australia ◽  
Fold Belts ◽  
Metamorphic Terranes ◽  
Host Rocks

Australia commenced separating from Antarctica some 85 million years ago, finally separating about 33 million years ago, and has been migrating northwards towards the Eurasian plate during that time. In the process, Australia, on its eastern side, progressively passed over a mantle hotspot. A magma plume intersected a variable lithocrust with various lithologic packages such as Phanerozoic sedimentary basins, fold belts and metamorphic terranes, and Precambrian rocks. As such, there was scope for compositional evolution of magmas through melting and assimilation, as well as plucking of host rocks to include xenoliths, and xenocrysts. The volcanic chain, volcanoes, and lava fields that are spread latitudinally along 2000 km of eastern Australia present a globally-significant volcanic system that provides insights into magma and crust interactions, into the variability of xenoliths and xenocrysts, into magma evolution dependent on setting, and into the mantle story of the Earth. The Cosgrove Volcano Chain is an example of this, and stands as a globally-unique potential megascale geopark.

scholarly journals Three-dimensional physical models of sedimentary basins as a resource for teaching-learning of geology

2018 ◽  
Vol 14 (4) ◽  
pp. 379-384 ◽  
Author(s):  
Celso Dal Ré Carneiro ◽  
Kauan Martins dos Santos ◽  
Thiago Rivaben Lopes ◽  
Filipe Constantino dos Santos ◽  
Jorge Vicente Lopes da Silva ◽  
...  
Keyword(s):  
Computational Models ◽  
Three Dimensional ◽  
Spatial Vision ◽  
Sedimentary Basins ◽  
3D Models ◽  
Physical Models ◽  
3D Objects ◽  
Three Dimensional Modeling ◽  
Three Dimensional Models ◽  
Teaching Learning

Three-dimensional modeling connects several fields of knowledge, both basic and applied. 3D models are relevant in educa-tional research because the manipulation of 3D objects favors students' acquisition of spatial vision, but in the Geosciences, there are few didactic publications in Portuguese on the subject. The authors develop an educational research project to produce three-dimensional models of didactic examples of sedimentary basins: the Paraná Basin (Silurian-Upper Cretaceous), the Tau-baté and the São Paulo basins (Neogene). 3D-compatible files will be produced to compose didactic and display material, from maps and geological-structural profiles of certain regional stratigraphic levels of each basin. The research challenges are: (a) to obtain an overview of the available resources for 3D modeling; (b) to evaluate their potential, characteristics, advantages and limitations for applications in Geology and Geosciences; (c) to create computational models of the basins; (d) to produce at least one physical model based on one of the computational models of each basin. The resources will subsidize training work-shops for in-service teachers, technical-scientific articles and Internet pages.

scholarly journals Delimitação e caracterização morfométrica da bacia hidrográfica do Riacho do Navio, Pernambuco, a partir de dados SRTM processados no QGIS

2021 ◽  
Vol 14 (3) ◽  
pp. 1530
Author(s):  
Ênio Gomes Flôr Souza ◽  
Antônio Henrique Cardoso do Nascimento ◽  
Ellen Abreu da Cruz ◽  
Dalbert De Freitas Pereira ◽  
Raquel Soares da Silva ◽  
...  
Keyword(s):  
Digital Elevation Models ◽  
Local Population ◽  
Shuttle Radar Topography Mission ◽  
Drainage Density ◽  
Terrain Analysis ◽  
Digital Elevation ◽  
Circularity Index ◽  
Average Slope ◽  
Elevation Model ◽  
Srtm Data

A bacia hidrográfica do Riacho do Navio, em Pernambuco, tem importante papel ao atender as demandas hídricas de animais, culturas agrícolas e da população local, sendo fundamental estudá-la de maneira mais específica, a fim de que sejam geradas informações que subsidiem a gestão de seus recursos ambientais. O objetivo deste estudo foi delimitar a bacia hidrográfica do Riacho do Navio e descrever suas características morfométricas (forma, rede de drenagem e relevo) a partir de dados Shuttle Radar Topography Mission (SRTM) processados no programa livre Quantum GIS (QGIS), via a ferramenta Terrain Analysis Using Digital Elevation Models (TauDEM). A bacia em questão possui 3.312,97 km2, sendo considerada de quinta ordem, com densidade de drenagem de 0,50 km km-2. Observou-se que a declividade média foi de 5,23%, sendo que mais de 86,61% da área da bacia apresentou declividades menores que 8%. O fator de forma, o coeficiente de compacidade e o índice de circularidade atingiram valores de 0,29; 2,10 e 0,22, indicando que a bacia possui formato alongado e, por conseguinte, baixa tendência a enchentes. Por outro lado, a sinuosidade e a declividade média do álveo podem favorecer a ocorrência de cheias em situações de chuvas intensas. O uso do QGIS e do TauDEM para tratamento de imagens SRTM se mostrou uma ferramenta eficiente, podendo auxiliar na gestão e no gerenciamento dos recursos hídricos da bacia do Riacho do Navio.   Delimitation and morphometric characterization of the hydrographic basin of Riacho do Navio, Pernambuco, based on SRTM data processed at QGIS A B S T R A C TThe Riacho do Navio watershed, in Pernambuco, has an important role in meeting the water demands of animals, agricultural crops and the local population, and it is essential to study it more specifically, in order to generate information that supports the management of its environmental resources. The objective of this study was to delimit the Riacho do Navio watershed and describe its morphometric characteristics (shape, drainage network and relief) from Shuttle Radar Topography Mission (SRTM) data, processed in the free program Quantum GIS (QGIS), via the Terrain Analysis Using Digital Elevation Models (TauDEM) tool. The watershed in question has 3,312.97 km2, being considered of fifth order, with drainage density of 0.50 km km-2. It was observed that the average slope was 5.23%, with more than 86.61% of the watershed area showing slopes less than 8%. The shape factor, the compactness coefficient and the circularity index reached values of 0.29; 2.10 and 0.22, indicating that the watersehd has an elongated shape and, therefore, low tendency to flooding. On the other hand, the sinuosity and the average slope of the riverbed can favor the occurrence of floods in situations of intense rains. The use of QGIS and TauDEM for the treatment of SRTM images proved to be an efficient tool, which can assist in the management and administration of water resources in the Riacho do Navio watershed.Keywords: physiographic analysis, Hydrology, digital elevation model, Semiarid, TauDEM.

scholarly journals DIACHRONIC RECONSTRUCTION OF LOST CULTURAL HERITAGE SITES. STUDY CASE OF THE MEDIEVAL WALL OF AVILA (SPAIN)

2018 ◽  
Vol XLII-2 ◽  
pp. 975-981 ◽  
Author(s):  
P. Rodríguez-Gonzálvez ◽  
S. Cardozo Mamani ◽  
A. Guerra Campo ◽  
L. J. Sánchez-Aparicio ◽  
S. del Pozo ◽  
...  
Keyword(s):  
Cultural Heritage ◽  
Laser System ◽  
3D Models ◽  
Fourth Dimension ◽  
Historical Sources ◽  
Heritage Sites ◽  
Archaeological Data ◽  
Main Challenge ◽  
Study Case ◽  
High Degree

The integration of the fourth dimension into the geospatial data allows to generate a diachronic model of Cultural Heritage (CH) assets, namely, a set of 3D models to represent it in various historical phases. This kind of reconstruction pursues a better understanding of the CH site/scenario, enriching the historical hypotheses as well as contributing to the conservation and decisionmaking process. Although the new geotechnologies have reduced the amount of fieldwork, the generation of 4D model implies the interpretation of heterogeneous historical information sources and their integration. However, this situation could reach a critical point when the study elements are no longer present. Their reconstruction will allow the digital preservation and maintenance of our culture. The main challenge is to harmonize the different historical and archaeological data sources available in relation with the current remains, to recover the lost CH assets with a high degree of reliability. This manuscript aims to examine the study case of a diachronic reconstruction by means of the use of the geotechnology Mobile Laser System (MLS) and reverse engineering techniques for a lost urban CH element, the citadel or <i>Alcázar</i> Gate of Ávila. Within this aim, the derived product is evaluated in terms of the achieved accuracy to assess its suitability on the basis of constructive interpretations required to integrate the historical sources in relation to current remains and the surrounding.

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