GEOLOGICAL STRUCTURE OF THE CAINOZOIC DEPOSITS OF THE SASYK ESTUARY COAST (THE NORTH-WEST NEAR BLACK REGION)

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.

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Pisanite from Parys Mountain, Anglesey

Mineralogical Magazine and Journal of the Mineralogical Society ◽

10.1180/minmag.1950.029.208.08 ◽

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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Coroboration of magnetotelluric investigations with other geophysical anomalies for a case study located in North-West to central part of Romania

10.5194/egusphere-egu2020-10242 ◽

2020 ◽

Author(s):

Natalia-Silvia Asimopolos ◽

Laurentiu Asimopolos

Keyword(s):

Transition Zone ◽

Sedimentary Cover ◽

Careful Analysis ◽

Geological Structure ◽

North West ◽

The North ◽

The Many ◽

Geophysical Anomalies

The results of the magnetoteluric investigations carried out along the profiles are presented in the form of sections in which the variations of the different parameters, the 2-D modeling, as well as the inversions.The results of the geophysical researches (magnetotellurics, gravity, geomagnetics) obtained were aimed at obtaining a unitary image on the deep geological structure in the investigated area. A number of information was obtained regarding such as:<ul><li>Determination of the thickness of the package of formations belonging to the post-tectogenetic sedimentary cover of the Transylvanian Depression; sedimentary sedimentary cover, conductive, with a maximum thickness of approximately 4000 m in the Pannonian Depression;</li> <li>Contouring of the Tethysian Major Suture (near the town of Alba Iulia in the Transylvanian Basin), represented by the Transylvanian nappes system (ofiolitic complex and sedimentary formations), with resistivities of about 500 Ohm*m, which separates two blocks with continental crust of different thicknesses (22- 27 km for Internal Dacids and 32-36 km for Median Dacids);</li> <li>Highlighting the change of nappes systems belonging to the Transylvanians, with a wide development both to the north (C&#259;p&#226;lnas-Techereu nappes and the nappes of Gro&#351;i and Cri&#351;), as well as to the east (the ophiolite complex and sedimentary cover), over the Biharia nappes system, respectively Central-Eastern Carpathian nappes; extension of the Codru and Biharia - Arie&#351;eni nappes, the last with higher resistivities (200 Ohm*m);</li> <li>Highlighting the transcrustal fault that marks the contact between the Inner Dacides and the Median ones;</li> <li>Individualization at the level of the lower crust of a transition zone; significant decrease of resistivity, as a consequence of the presence of the fluids in the transition zone, from the pressure in the pores from lithostatic type to the hydrostatic type (occurs at depths of 22 - 30 km and at temperatures of 350&#186; - 400&#186; C).</li> </ul>The electromagnetic data reflect the anomalies of electrical conductivity in a sensitive way, but due to the many causes that can generate them, a careful analysis of the particularities existing for each case, especially the superficial ones, was necessary.The correlation of the all the information provided in sections (resistivity, phases, density, magnetic susceptibility), inversions, modeling, lead to the validation of the model.

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The Geological Structure of the North-West Highlands of Scotland – revisited: Peach et al. 100 years on

Geological Society London Special Publications ◽

10.1144/sp335.2 ◽

2010 ◽

Vol 335 (1) ◽

pp. 7-27 ◽

Cited By ~ 5

Author(s):

Robert W. H. Butler

Keyword(s):

Geological Structure ◽

North West ◽

The North

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Geological Studies in the Dublin District. I. The Heavy Minerals of the Granite and the Contiguous Rocks in the Ballycorus District

Geological Magazine ◽

10.1017/s0016756800102559 ◽

1928 ◽

Vol 65 (1) ◽

pp. 12-25 ◽

Cited By ~ 4

Author(s):

F. Smithson

Keyword(s):

Geological Structure ◽

Heavy Minerals ◽

East Side ◽

The South ◽

Large Area ◽

Lower Carboniferous ◽

North West ◽

The North ◽

South West ◽

The Hill

From the southern shores of Dublin Bay there stretches to the south-west a broad granite intrusion with rocks of supposed Ordovician age on both sides of it. These rocks are metamorphosed near the granite, and the belt of metamorphism is wider on the south-east than on the north-west side, indicating, no doubt, that the plane of junction dips more steeply on the latter side. Near Dublin the Lower Carboniferous rocks rest unaltered upon the granite. On the south-east side, in the northern part of the county of Wicklow, the belt of Ordovician rocks is only some 2 miles wide, and a large area of supposed Cambrian rocks lies between it and the sea. Around the hill of Carrickgollogan a. patch of similar rocks appears incongruously in the middle of the Ordovician belt. After a study of the region to the south of Dublin one seems to be naturally drawn towards this small area around Carrickgollogan, for it presents a problem, the key to which may explain the geological structure of a much wider area.

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NEW TECHNOLOGY—A MAJOR IMPACT ON A PRODUCING FIELD: NORTH RANKIN GAS FIELD, NORTH WEST SHELF, AUSTRALIA

The APPEA Journal ◽

10.1071/aj91003 ◽

1992 ◽

Vol 32 (1) ◽

pp. 20

Author(s):

L. Tilbury ◽

T. Barter

Keyword(s):

New Technology ◽

Development Planning ◽

Geological Structure ◽

Lower Jurassic ◽

Production Performance ◽

Amplitude Analysis ◽

Gas Field ◽

North West ◽

The North ◽

Drilling Technology

New technology, especially the significant advances in 3D seismic interpretation techniques and drilling technology, has had a major impact on the development planning for the North Rankin Field.Significant advances have been made through the application of: horizon attribute processing, seismic amplitude analysis and long-reach drilling technology.Horizon attribute processing, including image processing techniques, has led to a better understanding of the structurally complex region on the northern flank of the field. These studies, coupled with new geological concepts related to opposing fault regimes, have concluded that good reservoir communication should exist across a fault zone previously thought to subdivide the field into compartments. The drilling of expensive, long-reach wells into the northern sector has thus been deferred, and may never be required, because of the newly developed structural model.Seismic amplitude analysis, coupled with geological modelling, upgraded the North Rankin West area and culminated in the recent significant appraisal/development well NRA22. This well was drilled from the North Rankin 'A' (NRA) platform to a target outside the main North Rankin Field in the adjacent Searipple Graben. NRA22 encountered well developed gas-bearing sands of Bathonian age which flowed at high rates (140 MMSCFGD).The application of long-reach drilling technology within Woodside has also had significant impact on development planning. The original development plan for North Rankin included a second platform in the northeast of the field. Better than expected production performance from NRA, related to across-fault reservoir communication, removed the necessity for a second platform. Large gas reserves in the Lower Jurassic 'NC' unit in the northeast have, however, required dedicated wells to improve ultimate recovery from this unit. The drilling of long-reach wells (at record drift) into the NC unit has provided better access to these reserves.Although North Rankin has been producing for over seven years with a total of 23 development wells drilled, understanding of the geological structure is still being improved by using new technology and ideas.

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An Analysis of Natural Factors Affecting the Dispersal and Establishment of Iron Age III Settlements in the Western Zayandehrand Basin (West and Northwest of Isfahan)

Journal of Geographical Research ◽

10.30564/jgr.v4i1.2630 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Masoomeh Dehkordi ◽

Alamdar Alian

Keyword(s):

Water Resources ◽

Iron Age ◽

Geological Structure ◽

The West ◽

Statistical Population ◽

Factors Affecting ◽

North West ◽

The North ◽

Ancient Times ◽

Communication Paths

Humans are always lenders to their surroundings which makes it possible to create habitable environments and create habitat patterns that fit the surrounding environment. In this research, settlement patterns of Iron Age III sites in the west and northwest of Isfahan was studied via GIS. The area studied is one of the most important but unknown areas of archaeological research due to its location in the center of the Iranian plateau and a link between the north-west and the south-west of the country. The environmental characteristics of the studied area have attracted the attention of humans since ancient times. Therefore, it was considered necessary to conduct archaeological excavations. To achieve this goal, the area was first studied archaeologically. As a result of this survey, approximately 50 ancient sites were identified which included the statistical population used for analysis. The effect of environmental variables on the distribution of settlements in the study area was investigated including altitude, slope (percentage and direction), climate, geological structure, distances and proximity to water resources, distance to and land use, and the proximity to communication paths. Through analytical-descriptive method, the factors affecting the formation and distribution of the establishment patterns of the period in question was studied. After analyzing the information and maps, the results indicated that among all the factors, three environmental factors were the most important in the formation of ancient settlements of the Iron Age III era in the west and northwest of Isfahan: factors relating to water resources, proximity to communication paths, and slope percentage and direction.

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Gold-tourmaline mineralization in carbonaceous shales of the Kumak deposit (South Ural)

Gornyi Zhurnal ◽

10.17580/gzh.2020.12.02 ◽

2020 ◽

pp. 11-15

Author(s):

A. V. Kolomoets ◽

◽

A. V. Snachev ◽

M. A. Rassomakhin ◽

◽

...

Keyword(s):

Early Carboniferous ◽

Geological Structure ◽

High Grade ◽

North West ◽

Gold Ore ◽

North East ◽

The North ◽

Carbonaceous Shales ◽

Ore Mineralization ◽

Gold Ore Deposit

The article discusses the geological structure of the Kumak gold ore deposit, confined to the Early Carboniferous Anikhov graben of the East Ural uplift. It is composed of sericite-quartz-carbon and quartz-carbon-tourmaline schists of the Bredy Formation (C1bd). Black shale deposits are carbonaceous type and belong to terrigenous-carbonaceous and silicon-carbonaceous formations. Among the main minerals in shales are noted: quartz, sericite, carbonates, sulfides, tourmaline and carbonaceous matter. The field is characterized by a wide variety of gold ore mineralization. Rich ore zones are noted at the intersection of the East Anikhov faults oriented in the north–south direction and the branching tensile fractures in the north-north-east and north-west directions. In the ore mineral association prevailing here, finely dispersed gold is associated with small crystals of pyrite, arsenopyrite and concentrates nearby abundant tourmaline areas. The fine intergrowth of tourmaline and gold indicates the synchronism of their formation and allows us to distinguish a quartz-tourmaline gold ore formation within the Kumak deposit, comparable with a number of objects in East Transbaikal and Tuva. The most probable source of tourmaline mineralization in sericite-quartz-carbon schists could be metamorphically transformed boron-containing marine sediments saturated with clay particles and Corg. The microprobe study of gold grains taken from carbonaceous shales and weathering crusts made it possible to attribute them to the high-grade (919–1000) type, which is the leading one in the gold ore mineralization of the considered deposit. It is established that in the zone of hypergenesis, gold grains are not homogeneous. Here, secondary redeposition of gold takes place in the form of small spongy high-grade aggregates, as well as the formation of a rim on some grains with clear signs of refinement and purification from impurity elements. The geological works were carried out under State Contract No. 0246-2019-0078. The analyses were supported by the regional Grant for Science and R&D, Agreement No. 23 dated August 18, 2019. The studies into gold composition were executed in the framework of state-financed scientific topic No. AAAA-A19-119072390050-9. The authors express thanks to S. A. Yagudin for the analysis implementation and to E. O. Kalistratov for the help in description of polished sections. Further thanks are extended to R. S. Kisil and V. S. Panteleev for the help in the field works.

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