scholarly journals Geoturism in Africa. the Simien Mountains

2021 ◽  
Vol 7 ◽  
pp. 90-94
Author(s):  
K.A. Novoselov
Keyword(s):  
Geological Structure ◽  
The North ◽  
Shield Volcanoes ◽  
Ethiopian Plateau

The paper is dedicated to the geological structure of Ethiopia and Simien Mountains, which are located in the northern part of the North Ethiopian Plateau composed of Oligocene plateau basalts hosting Oligocene-Miocene shield volcanoes.

Subglacial topography and thickness of ice caps on the Argentine Islands

2019 ◽  
Vol 31 (6) ◽  
pp. 332-344 ◽  
Author(s):  
Jānis Karušs ◽  
Kristaps Lamsters ◽  
Anatolii Chernov ◽  
Māris Krievāns ◽  
Jurijs Ješkins
Keyword(s):  
Land Surface ◽  
Geological Structure ◽  
Aerial Images ◽  
Ice Thickness ◽  
Ice Caps ◽  
The North ◽  
Prevailing Wind Direction ◽  
Aerial Vehicle ◽  
Subglacial Topography ◽  
Ground Penetrating

AbstractThis study presents the first subglacial topography and ice thickness models of the largest ice caps of the Argentine Islands, Wilhelm Archipelago, West Antarctica. During this study, ground-penetrating radar was used to map the thickness and inner structure of the ice caps. Digital surface models of all studied islands were created from aerial images obtained with a small-sized unmanned aerial vehicle and used for the construction of subglacial topography models. Ice caps of the Argentine Islands cover ~50% of the land surface of the islands on average. The maximum thickness of only two islands (Galindez and Skua) exceeds 30 m, while the average thickness of all islands is only ~5 m. The maximum ice thickness reaches 35.3 m on Galindez Island. The ice thickness and glacier distribution are mainly governed by prevailing wind direction from the north. This has created the prominent narrow ice ridges on Uruguay and Irizar islands, which are not supported by topographic obstacles, as well as the elongated shape of other ice caps. The subglacial topography of the ice caps is undulated and mainly dependent on the geological structure and composition of magmatic rocks.

Reconstruction of the Reservoir Fine Structure by Using Scattering Attributes

2021 ◽  
Author(s):  
Vladimir Cheverda ◽  
Vadim Lisitsa ◽  
Maksim Protasov ◽  
Galina Reshetova ◽  
Andrey Ledyaev ◽  
...  
Keyword(s):  
Seismic Data ◽  
Numerical Experiments ◽  
Seismic Waves ◽  
Fractured Reservoirs ◽  
Three Dimensional ◽  
Geological Structure ◽  
Discrete Elements ◽  
Digital Twin ◽  
The North ◽  
Slip Surfaces

Abstract To develop the optimal strategy for developing a hydrocarbon field, one should know in fine detail its geological structure. More and more attention has been paid to cavernous-fractured reservoirs within the carbonate environment in the last decades. This article presents a technology for three-dimensional computing images of such reservoirs using scattered seismic waves. To verify it, we built a particular synthetic model, a digital twin of one of the licensed objects in the north of Eastern Siberia. One distinctive feature of this digital twin is the representation of faults not as some ideal slip surfaces but as three-dimensional geological bodies filled with tectonic breccias. To simulate such breccias and the geometry of these bodies, we performed a series of numerical experiments based on the discrete elements technique. The purpose of these experiments is the simulation of the geomechanical processes of fault formation. For the digital twin constructed, we performed full-scale 3D seismic modeling, which made it possible to conduct fully controlled numerical experiments on the construction of wave images and, on this basis, to propose an optimal seismic data processing graph.

scholarly journals PEMODELAN BAWAH PERMUKAAN MANIFESTASI MINERAL DENGAN METODE GEOMAGNETIK DAERAH PACITAN JAWA TIMUR

KURVATEK ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 25-33
Author(s):  
Fatimah Fatimah
Keyword(s):  
Image Data ◽  
Geological Structure ◽  
Magnetic Data ◽  
Magnetic Intensity ◽  
Magmatic Arc ◽  
The North ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Extensional Structure ◽  
Anomaly Map

Tulakan Subdistrict, Pacitan Regency, East Java Province. This area is part of the Southern Mountain Zone of East Java, which is the Sunda-Banda magmatic arc of Oligo-Miocene age, where there are alterations and indications of valuable ore minerals. Field magnetic data is taken in an area of 1 x 1 km, with the looping method on the grid trajectory within 200 x 100 m. Then, magnetic data correction and data processing were carried out with Oasis Montaj. From the magnetic anomaly map, the value of high magnetic intensity in the southern part is fresh (intrusive) andesit-dasitic rock as host rock which causes alteration, in the middle has a low magnetic intensity value which is in the direction of the relatively NE-SW river direction, whereas in the north with high intensity is fresh andesite lava. From the image data, it can be seen that the straightness pattern of the geological structure which is dominated by the extensional structure with the direction of NE-SW and E-W is the main trap of epithermal veins carrying ore mineralization mainly Cu, Pb in the study area.

scholarly journals Analysis of the data of hydrogeochemical monitoring of groundwater in the North Sivash artesian basin

2019 ◽  
pp. 64-71
Author(s):  
K. Ya. Bulakhova ◽  
S. M. Sudarikov
Keyword(s):  
Research Area ◽  
Geological Structure ◽  
Hydrogeological Model ◽  
Artesian Basin ◽  
Correlation And Regression Analysis ◽  
The North ◽  
Gypsum Content ◽  
Definition Of ◽  
Aquifer Complex ◽  
Made In

The results of hydrogeochemical monitoring of the Sarmat-Meotis-Pontic sediments aquifer complex of the North Sivash artesian basin have been analyzed. The analysis based on a routine observations for 16 producing wells. The observations were made in the period from 2014 to 2017 years. A correlation and regression analysis has been made for definition of dependencies between changes in the concentrations of the normalized components. The results obtained allow us to evaluate the main factors of formation of the chemical composition of groundwater. At the present stage, metamorphosed waters are pulled up from the lower strata of the complex, that leads to an increase in the amount of mineralization. The formation of sulphate waters is primarily associated with the peculiarities of the geological structure, namely, the high gypsum content of quaternary deposits and the presence of hydraulic connection with the overlying aquifers. One of the reasons for the formation of sulphate waters is the anthropogenic impact associated with the close location of the acid accumulator containing sulfur tailing. The results obtained allow us to proceed to the next stage of the survey — the creation of a natural hydrogeological model of the research area and the carrying of the thermodynamic modeling.

scholarly journals Geological Structure Analysis to Determine the Direction of the Main Stress at Western Part of Kolok Mudik, Barangin District, Sawahlunto, West Sumatera

2017 ◽  
Vol 2 (1) ◽  
pp. 46
Author(s):  
Miftahul Jannah ◽  
Adi Suryadi ◽  
Muchtar Zafir ◽  
Randi Saputra ◽  
Ihsanul Hakim ◽  
...  
Keyword(s):  
Structure Analysis ◽  
Normal Fault ◽  
Geological Structure ◽  
Reverse Fault ◽  
Geological Structures ◽  
The North ◽  
Main Stress

On the study area there are three types of structure, those are fault, fold and joint. Types of fault were found  in the study area, reverse fault with the strike/dip is N215oE/75o, normal fault has a fault directions N22oE and N200oE with pitch 35o, and dextral fault with pitch 10o and strike N219oE. Fold and joint structures used to determine the direction of the main stress on the study area. Further, an analysis used stereonet for data folds and joints. So that from the data got three directions of main stress, those are Northeast – Southwest (T1), North – South (T2) and Southeast – Northwest (T3). On the Northeast – Southwest (T1) stress there are four geological structures, anticline fold at ST.3 , syncline folds at ST. 13a, ST. 13b, ST. 13c and ST. 33, chevron fold at ST. 44 and joint at ST. 2. On the North – South (T2) stress there are three geological structures, those are syncline fold at ST. 35, anticline fold at ST. 54 and joints at ST. 41, ST. 46 and ST. 47. On the Southeast – Northwest (T3) stress were also three geological structures, those are chevron fold at ST 42a, overturned fold at ST. 42b, syncline fold at ST. 42c and joints at ST. 5 and ST. 34.

Walkabove VSP with seismic-while-drilling technology: flawless operation in a highly deviated well

2013 ◽  
Vol 53 (2) ◽  
pp. 454
Author(s):  
Adrian Cristian Sanchez Rodriguez ◽  
Leon Dahlhaus ◽  
Konstantin Galybin ◽  
Andrew Vigor ◽  
Grant Skinner ◽  
...  
Keyword(s):  
Seismic Profile ◽  
Geological Structure ◽  
Surface Source ◽  
North West ◽  
The North ◽  
Bottom Hole ◽  
Surface Time ◽  
Drilling Technology ◽  
Bottom Hole Assembly

SWD was recently used in the North West Shelf of Australia to acquire time-depth measurements and to obtain a vertical seismic profile (VSP) while pulling out of hole. The use of SWD technology greatly enhanced the understanding of geology by acquiring a more precise geophysical picture of the subsurface, leading to better understanding of the subsurface and placement of wells in the future. A vertical incidence VSP was acquired in an offshore deviated well for a client on the Australian North West Shelf. The data was acquired using a moving-surface source, suspended from a boat, and a four-component downhole sensor in the bottom hole assembly (BHA). The downhole data was acquired using three orthogonal geophones and a single hydrophone measurement at each VSP level. This was recorded while pulling out of hole, and processed once the tool was on surface. Time picking accuracy of the downhole data is ±0.5 ms with the frequency range 6–90Hz, both comparable to Wireline. The repeatability of the hydrophone and geophone time picks was also excellent with the average difference being 0.2 ms and maximum 0.8 ms. High resolution VSP images beneath the well in addition to corridor stacks were derived from the geophone and hydrophone data, showing the geological structure of the reservoir. The quality of the data acquired allowed the client to remove the need for a wireline VSP run; it, therefore, saved significant rig time and costs associated with it, reduced the chances of getting stuck, and significantly reduced the seismic uncertainty.

Walcot Gibson 1864-1941

1943 ◽  
Vol 4 (12) ◽  
pp. 271-275
Keyword(s):  
East Africa ◽  
Geological Structure ◽  
Geological Mapping ◽  
Geological Survey ◽  
Intimate Contact ◽  
The North ◽  
South Wales ◽  
New Information ◽  
Original Survey ◽  
The One

Walcot Gibson was born at Bromsgrove, Worcestershire, on 24 August 1864. His father was a bank manager from the north country and his mother was Cornish, and they had three sons and one daughter. Gibson was educated at the Bromsgrove School and about 1882 went to Mason College, Birmingham, now the University of Birmingham. Charles Lapworth who had distinguished himself by his great researches in the south of Scotland had just been appointed to the chair of Geology at Mason College and thirty-one years later (1913) he records that Gibson was his first geological pupil. His interest in geology and geological mapping was developed by intimate contact with Lapworth and was sustained by a coterie of ardent amateur geologists, among them Joseph Landon, Fred Cullis and C. J. Gilbert. This period clearly determined Gibson’s choice of a career. After a course at the Royal College of Science he set out in 1889 on Lapworth’s advice for South Africa where he was engaged for two years on mineral surveys in the Rand goldfields and elsewhere. From there he moved to East Africa where he was engaged for another two years on mineral surveys for the East Africa Company. He returned to this country an experienced geologist and surveyor and in 1893 he joined H.M. Geological Survey in which service he remained for thirty-two years until his retirement in 1925. This was an important period in the history of the Geological Survey for owing to strong representations that the old Survey had become obsolete both in topography and geology, the House of Commons in 1891 sanctioned a resurvey of the great South Wales Coalfield on the scale of six inches to the mile. The first mapping of that field initiated by Logan and de la Beche was on the one-inch scale and was completed about 1845, the year in which the Geological Survey was transferred from the Board of Ordnance. The enormous developments which had taken place since the original survey had far outstripped the knowledge of the geological structure of the field and new information had become urgently necessary.

Caledonian magmatism record within Hebridean Terrane? Loch Roag dyke (Lewis Island, northern Scotland) non-peridotitic xenoliths and megacrysts as messengers from deep lithosphere.

2020 ◽  
Author(s):  
Daniel Buczko ◽  
Magdalena Matusiak-Małek ◽  
Brian J. G. Upton ◽  
Theodoros Ntaflos ◽  
Sonja Aulbach ◽  
...  
Keyword(s):  
North Atlantic ◽  
Parental Magma ◽  
Geological Structure ◽  
Trace Element Composition ◽  
Isotopic Ratios ◽  
The North ◽  
Source Regions ◽  
Mantle Sources ◽  
History Of ◽  
North Atlantic Craton

<p>The northernmost part of Scotland – the Hebridean Terrane – is formed of Archean rocks originally being part of the Laurentian North Atlantic Craton. The geological history of the terrane is well recognised, however details of its internal structure remain unknown. The Eocene (Faithfull et al. 2012, JGS) Loch Roag monchiquite (Lewis Island) sampled deep-seated lithologies, providing insight on evolution and geological structure of the deeper lithosphere of the Hebridean terrane. The monchiquite comprises abundant xenoliths of ultramafic, mafic and felsic rocks. The peridotitic xenoliths represent pieces of Archean mantle underlying marginal parts of the North Atlantic Craton, whereas the origin of non-peridotitic lithologies is uncertain.</p><p>The studied suite of samples comprises two groups: 1) “xenoliths” of diorites (plagioclase, clinopyroxene, orthopyroxene, apatite, opaques) and biotite clinopyroxenites (+apatite), 2) “megacrysts” of clinopyroxene and K-feldspar, both with inclusions of clinopyroxene, biotite and apatite. Megacrysts of alkali-rich feldspar associated with corundum and HFSE-bearing minerals, and composite xenoliths formed of pyroxenite and K-feldspar-rich lithology have also been described from this locality (Menzies et al., 1986, Geol. Soc. Australia Spec. Pub.; Upton et al., 2009, Mineral. Mag.).</p><p>We interpret the “xenoliths” as products of crystallization of fractionated mafic melt(s). The primary character of Sr isotopic ratios in plagioclase (<sup>87</sup>Sr/<sup>86</sup>Sr <0.702) suggests that parental melt of those lithologies originated from melting of depleted lithospheric mantle sources. The “megacrysts” represent fragments of disintegrated alkaline pegmatite(s) formed from melt of plausible mantle origin, possibly enriched (<sup>87</sup>Sr/<sup>86</sup>Sr in feldspar >0.704).</p><p>Trace element composition, similar Sr isotopic ratios of minerals and textural features of “xenoliths” and “megacrysts” groups suggest their close genetic relationship. This geochemical resemblance may reflect crystallisation from primarily similar melt(s) and source regions affected by similar metasomatism. Petrographic features observed in rocks described by Upton et al., (2009) imply that the parental magma of megacrysts might have intruded the rocks forming the xenoliths group. Moreover, the Rb-Sr ages of xenoliths (Der-Chuen et al., 1993, GCA) indicate crystallisation during (or shortly after) Caledonian orogeny. Preliminary age relationship between groups will be determined by on-going Rb-Sr dating of megacrysts.</p><p>Xenoliths similar to diorites from Loch Roag were reported by Badenszki et al. (2019, JoP) from the Midland Valley terrane (“metadiorites” of protolith ages ca. 415 Ma). They were interpreted as products of alkaline syn-/post-collisional Caledonian magmatism. Our study shows that non-peridotitic xenoliths from Loch Roag dyke might represent a record of similar (or the same) magmatism in the northernmost, “Laurentian” part of Scotland. This study presents the first report of such Caledonian magmatism record within the Hebridean Terrane.</p><p>Founded by Polish National Science Centre grant no. UMO-2016/23/B/ST10/01905, part of the data was obtained thanks to the Polish-Austrian project no. WTZ PL 08/2018.</p>

Pisanite from Parys Mountain, Anglesey

1950 ◽  
Vol 29 (208) ◽  
pp. 63-67
Author(s):  
Leslie Bor
Keyword(s):  
First Record ◽  
First World War ◽  
Geological Structure ◽  
East Side ◽  
World War ◽  
North West ◽  
The North ◽  
The First World War ◽  
First World ◽  
Geological Research

During the Manchester University's 1946 geological excursion to Anglesey, a visit was made to Parys Mountain. At this locality small quantities of an attractive light blue mineral were found capping pyrite veins and in clefts in the rock. Larger finds were obtained in an artificial cavern which extended for fifty or sixty feet into the south-east side of the excavated pit. A specimen weighing 2½ pounds and consisting of silicified shale veneered with the pale blue mineral was collected by the author and examined in the geological research laboratory at Manchester University during the session 1948–1949. The blue mineral was identified as pisanite, and this is the first record of pisanite as a British mineral.Parys Mountain is situated in the north-west of Anglesey close to Amlwch. Copper and to a smaller extent lead were mined throughout a period exceeding one hundred and fifty years, but operations have completely ceased since the first world war. The geological structure of the district need only be briefly outlined for the purpose of this study.

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