scholarly journals Geology of a Neogene caldera cluster in Northeast Iceland – clues into rift zone architecture on a young Iceland

2021 ◽  
Author(s):  
Steffi Burchardt ◽  
Birgir Oskarsson ◽  
Ludvik Gustafsson ◽  
Silvia Berg ◽  
Morten Riishuus
Keyword(s):  
Rift Zone ◽  
Flood Basalts ◽  
Current State ◽  
Geological Map ◽  
Silicic Magmatism

The Borgarfjörður-Loðmundarfjörður area in Northeast Iceland hosts an unusual volume of silicic rocks, as well as volcanic and sub-volcanic structures emplaced in the Miocene between 13.5 and 12.2 Ma. Here, we summarise the geology of the area and present a new geological map to summarise the current state of knowledge. We describe the prominent features of the volcanic centres, as well as regional marker horizons. Notably, the volume of silicic rocks, the distribution of eruptive centres, calderas, and intrusion swarms, as well as the interplay between regional flood basalts and silicic magmatism indicate a rift zone architecture different to that of the present day.

scholarly journals Geological structure of the Pre-jurassic basement of the Yugansk-Koltogorsk zone of the West Siberia

LITOSFERA ◽  
2018 ◽  
pp. 839-858 ◽  
Author(s):  
Kirill S. Ivanov ◽  
Stepan V. Berzin ◽  
Nadezhda V. Vakhrusheva ◽  
Nikolai P. Kostrov ◽  
Olga E. Pogromskaya
Keyword(s):  
Inductively Coupled Plasma ◽  
Rift Zone ◽  
West Siberia ◽  
Geological Structure ◽  
The West ◽  
X Ray ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Geological Map ◽  
Rift Zones

Subject of the study.We have carried out an additional exploration on petrography, petrochemistry, geochemistry, geochronology and biostratigraphy of rock complexes of the Yugansk-Koltogorsk (central part of West Siberia).Materials and methods.The materials are core samples from wells that penetrated the Pre-Jurassic basement rock complexes The used methods are as follows: X-ray spectrum microanalysis (Cameca SX 100, JEOL-733 Superprobe); the silicate analysis of the rocks (СРМ-18 and EDX-100); mass-spectroscopy with inductively coupled plasma (ICP-MS) (ELAN-9000 and Element2); zircons were analysed with a high resolution ionic microprobe SHRIMP-II (U-Pb); Ar-Ar dating was carried out by Micromass 5400; biostratigraphy, petrochemestry.Results.A geological map of Yugan-Koltogor zone of the central part of West-Siberian plate in a scale 1:500 000 was created. The map is a set of informational geological, geophysical and other layers. It was established that age of granites is Early Permian, the basalts of the rift zone began to form 268.4 ± 7.5 Ma ago (Ar-Ar). Conclusions. Volcanism in the axial rift zones of the West-Siberian megabasin basement began earlier than it is supposed before our study and significantly earlier of that of trap basalts of Siberian platform.

scholarly journals TO THE QUESTION OF THE CARTOGRAPHIC SUPPORT OF GEOLOGICAL EXPLORATION WORKS

2019 ◽  
Vol 6 (2) ◽  
pp. 235-241
Author(s):  
Marzhan Rakhymberdina ◽  
Dinara Nurmoldakyzy ◽  
Rustam Sagadiyev
Keyword(s):  
Industrial Development ◽  
Raw Materials ◽  
The State ◽  
Mineral Deposits ◽  
Geological Exploration ◽  
Current State ◽  
Geological Map ◽  
Three Sheets ◽  
The Republic ◽  
Stable Source

The article is devoted to the current state of geological study of the territory of the Republic of Kazakhstan and the update of the State geological map of 1 : 200 000 scale according to the results of geological studies of the three sheets of M-44-XXVIII, XXIX, XXX. The article shows a detailed description of the updated territory, in order to update the data on mineral deposits, which should ensure the industrial development of Kazakhstan with a stable source of raw materials.

scholarly journals Update of the seamless 1:500 000 scale geological map of Greenland based on recent field work in the Wandel Sea Basin, eastern North Greenland

2018 ◽  
pp. 39-42
Author(s):  
Kristian Svennevig
Keyword(s):  
Basic Research ◽  
Field Work ◽  
The Arctic ◽  
Digital Map ◽  
The Past ◽  
Geological Surveys ◽  
Current State ◽  
Geological Maps ◽  
Geological Map ◽  
North Greenland

Geological maps are core products of national geological surveys and represent the sum of geological knowledge of any given area. However, dedicated and extensive mapping projects in the Arctic are mostly a thing of the past due to difficulty in financing such costly basic research efforts. Today, an overview of the geology of Greenland is portrayed by a seamless digital 1:500 000 scale geological map (Kokfelt et al. 2013; Pedersen et al. 2013), based on printed maps on this scale produced since 1982 by the Geological Survey of Denmark and Greenland (GEUS; see Holst et al. 2013). The digital map now makes it possible to update smaller areas with new, published or otherwise quality-controlled geological data (e.g. Kolb et al. 2016). This ensures that the map reflects the current state of geological knowledge without undertaking extensive new mapping to update individual map sheets, as has previously been the modus operandi. An online version of the map is available from www.greenmin.dk/map. However, procedures are required to ensure that updates are carried out routinely and that the quality and coherence of the updated map is of the Survey’s standards. Results of recent field work in the Wandel Sea Basin (Fig. 1) and in particular the publication of a new geological map sheet Kilen on a scale of 1:100 000 (Svennevig in press) have implications for the geology shown on the above mentioned 1:500 000 scale seamless geological map of Greenland. The post-Devonian part of this map in eastern North Greenland has been updated according to the results of studies published since the publication of the original printed maps (Bengaard & Henriksen 1986; Jepsen 2000). The changes do not call for an update of the 1:2 500 000 scale geological map of Greenland (Henriksen et al. 2009).

scholarly journals The plume-dependent granite-rhyolite magmatism

LITOSFERA ◽  
2018 ◽  
pp. 692-705 ◽  
Author(s):  
Viktor N. Puchkov
Keyword(s):  
Continental Crust ◽  
Oceanic Islands ◽  
Flood Basalts ◽  
Magmatic Rocks ◽  
Oceanic Plateaus ◽  
Igneous Provinces ◽  
Plume Magmatism ◽  
Granite Magmatism ◽  
Silicic Magmatism

The plume-dependent magmatism is widespread and well justified. The bulk of it is represented by flood basalts, basalts of oceanic islands (OIB), and basalts of oceanic plateaus (OPB), though the whole scope of plume magmatism is very diverse. A noticeable role among them is played also by acid (silicic) magmatic rocks - rhyolites and granites. Two main types of plume magmatism are recognized. The first belongs to Large Igneous Provinces (LIP) and is thought to be born at the Core-Mantle boundary within structures, called superswells, that produce giant, short-living mantle upwellings, resulting in abundant volcanism on the Earth’s surface. The second type is represented by linear volcanic chains characterized by regular age progressions. They are formed by single plumes - thin ascending mantle flows, acting during longer periods of time. It is shown that the abundance of silicic magmatism strongly depends on the type of the earth’s crust. Among flood basalts of continents, silicic magmatism is usually present, subordinate in volume to basalts and belongs to a bimodal type of magmatism. But in some cases LIP in continents are formed predominantly by silicic rocks; they are given the name Silicic LIPS, or SLIPS. In oceans, LIP are fundamentally basaltic with no considerable volume of silicic volcanics, if any. The time-progressive volcanic chains in continents are rare and usually comprise a noticeable silicic component. In oceans, the chains are composed mostly of basalts (OIB type), though in the top parts of volcanoes more acid and alkaline differentiates are present; usually they lack rhyolites and granites, except the cases of a presence of some strips of continental crust or anomalously thick oceanic crust. This review can lead to a thought of an important role of melting of continental crust in formation of plume-dependent rhyolite-granite magmatism. As for the Urals, the proofs for a presence of plume-dependent magmatism in its history were presented only recently. Among the plume episodes, some are characterized by presence of silicic components, in particular: Mashak (1380-1385 Ma), Igonino (707-732 Ma), Man’khambo (mainly Cambrian), Ordovician Kidryasovo, Stepninsky (Permian) and Urals-Siberian (Triassic).

scholarly journals Lithostratigraphy of the early Tertiary volcanic rocks of central West Greenland

1975 ◽  
Vol 69 ◽  
pp. 17-24
Author(s):  
N Hald ◽  
A.K Pedersen
Keyword(s):  
Marine Sediments ◽  
Volcanic Rocks ◽  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Flood Basalts ◽  
West Greenland ◽  
Early Tertiary ◽  
Volcanic Sequence ◽  
Geological Map

A sequence of flood basalts, in places more than 8-10 km thick, was erupted during the Early Tertiary in the central part of West Greenland between latitudes 69° and 73°N. The volcanic rocks rest on Precambrian metamorphic rocks and non-marine and marine sediments from the Cretaceous and Paleocene. The lower part of the volcanic sequence is dominated by tholeiitic olivinerich basalts and picrite basalts, whereas the upper part is characterized by tholeiitic basalts with plagioclase as the dominant phenocryst mineral; transitional and alkaline lavas and tuffs are found, especially in the upper part of the sequence. The geology of the Tertiary igneous rocks has been summarized by Munck & Noe-Nygaard (1957), Rosenkrantz & Pulvertaft (1969) and Clarke & Pedersen (in press). However, until now no formal lithostratigraphy has been established. A geological map at scale 1:100 000 covering the greater part of Nugssuaq (sheet Agatdal-70 V. 1 Nord) has been published by GGU.

scholarly journals Early Tertiary lavas and sills on Traill Ø and Geographical Society Ø, northern East Greenland: petrography and geochemistry

1996 ◽  
Vol 171 ◽  
pp. 29-43
Author(s):  
N Hald
Keyword(s):  
Genetic Relationship ◽  
Rift Zone ◽  
Flood Basalts ◽  
East Greenland ◽  
Geographical Society ◽  
Incompatible Elements ◽  
Early Tertiary

The Early Tertiary extrusion of flood basalts in East Greenland was accompanied by intrusion of numerous sills in the Upper Palaeozoic arid Mesozoic sediments of the N–S trending East Greenland rift zone. With a few exceptions the lavas and sills have low contents of Ti and other incompatible elements, indicating a genetic relationship with the lavas and sills north of Kejser Franz Joseph Fjord rather than with the lavas in the Scoresby Sund area. Two sills are described in greater detail. The first, from Geographical Society Ø, is 60 m thick and homogeneous throughout. The second, from southern Traill Ø, is more than 150 m thick and atypical as it ranges in composition from low-Ti tholeiite to diorite.

scholarly journals Chapter 2.3 Dronning Maud Land Jurassic volcanism: volcanology and petrology

2021 ◽  
pp. M55-2018-89
Author(s):  
Arto V. Luttinen
Keyword(s):  
Upper Mantle ◽  
Rift Zone ◽  
Flood Basalt ◽  
Magnetic Polarity ◽  
Crustal Material ◽  
Magmatic Differentiation ◽  
Flood Basalts ◽  
Mantle Reservoir ◽  
Normal Polarity ◽  
Dronning Maud Land

AbstractThe Jurassic igneous rocks of Dronning Maud Land represent Karoo flood basalt magmatism in Antarctica. Fifty years of research has documented systematic differences between magmas associated with the Karoo rift-zone (Vestfjella and Ahlmannryggen) and the rift-shoulder (Sembberget, Kirwanveggen) settings. The 189–182 Ma rift-zone tholeiites were chemically diverse and mainly formed compound-braided flow fields which record several magnetic polarity reversals. In contrast, the c. 181 Ma rift-shoulder tholeiites were chemically uniform and formed thick tabular sheet lavas within a single normal polarity period. The volcanic architecture! records a long initial phase of slow eruptions from shield volcanoes in the initial rift and a brief phase of voluminous fissure eruptions flooding the rift shoulder. All of the major magma types in the rift-zone and rift-shoulder settings belong to a Nb-depleted category of Karoo flood basalts and were mainly derived from depleted convective upper mantle by magmatic differentiation. Pyroxenite-rich mantle components may have been significant sources for the most enriched magma types. Geochemical fingerprints of recycled crustal material imply that the Nb-depleted Karoo tholeiites may have been derived from mildly subduction-modified parts of the same overall upper-mantle reservoir which has been associated with the Ferrar tholeiites.

scholarly journals GEOLOGICAL ADDITIONAL RESEARCH OF PREVIOUSLY INVESTIGATED AREAS AND CREATION OF THE STATE GEOLOGICAL MAP (1:200 000) – IMPORTANT STAGE OF GEOLOGICAL RESEARCH OF UKRAINE TERRITORY (ACHIEVEMENTS AND PROBLEMS)

2018 ◽  
pp. 3-12 ◽  
Author(s):  
M. M. Kostenko
Keyword(s):  
First Generation ◽  
The State ◽  
Additional Research ◽  
State Budget ◽  
Main Work ◽  
Current State ◽  
Geological Map ◽  
Mining Works ◽  
Almost All ◽  
Geological Research

The article deals with the current state and problems of the main work directions in regional geological research of the Ukraine territory – the geological additional research of previously studied areas and creation of the State Geologiсal Map of 1:200 000 scale. The analysis of the new gene­ration of State Geological Maps certifies that, compared to the first generation maps (1958–1974), they differ much informatively and scientifically substantiated and are the basic geological basis for planning and conducting of almost all types of geological exploration, geoengineering, geo-ecological, hydrogeological and mining works. The emphasis is placed on the fundamental foundations of scientific and methodological support of continuously developing and updating works including stratigraphic, tectonic, geophysical, petrological, petrographic, laboratory-analytical and geoinformation bases. It is shown that due to the miserable financing of works from the State budget, the current state of regional geological researches in Ukraine is critical.

ESEM - A multipurpose surface Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 632-633 ◽  
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Environmental Scanning ◽  
Gas Composition ◽  
Saturated Water Vapor ◽  
Surface Electron ◽  
Current State ◽  
Saturated Water ◽  
New Type ◽  
Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

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