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Torfajökull Volcanic System
Torfajökull ( Icelandic for "Torfi's glacier"; ) is a rhyolitic stratovolcano, with a large caldera (central volcano) capped by a glacier of the same name and associated with a complex of subglacial volcanoes. Torfajökull last erupted in 1477 and consists of the largest area of silicic extrusive rocks in Iceland. This is now known to be due to a VEI 5 eruption 55,000 years ago. Geography The volcano is located north of Mýrdalsjökull and south of Þórisvatn Lake, Iceland. To its south-west is the volcano and glacier of Tindfjallajökull and almost directly to its west is the volcano of Hekla. Adjacent to the southern edge of its glacier of Torfajökull it has a peak of but the south-eastern caldera margin also extends to the glacier of Kaldaklofsjökull which is on the western slopes of a peak called Háskerðingur that is high. Laufafell dome at is at the north-western edge of the Torfajökull volcanic system and almost halfway between Hekla and the glacier of Torfajök ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iceland
Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the region's westernmost and most list of countries and dependencies by population density, sparsely populated country. Its Capital city, capital and largest city is Reykjavík, which is home to about 36% of the country's roughly 380,000 residents (excluding nearby towns/suburbs, which are separate municipalities). The official language of the country is Icelandic language, Icelandic. Iceland is on a rift between Plate tectonics, tectonic plates, and its geologic activity includes geysers and frequent Types of volcanic eruptions, volcanic eruptions. The interior consists of a volcanic plateau with sand and lava fields, mountains and glaciers, and many Glacial stream, glacial rivers flow to the sea through the Upland and lowland, lowlands. Iceland i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matrix (geology), groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite. Its high silica content makes rhyolitic magma extremely viscosity, viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been used extensively for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignimbrite
Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrounding atmosphere. New Zealand geologist Patrick Marshall (1869–1950) coined the term ''ignimbrite'' from the Latin ''igni-'' [fire] and ''imbri-'' [rain]. Ignimbrites are made of a very poorly sorted mixture of volcanic ash (or tuff when Lithification, lithified) and pumice lapilli, commonly with scattered lithic fragments. The ash is composed of glass shards and crystal fragments. Ignimbrites may be loose and unconsolidated, or lithified (solidified) rock called lapilli tuff. Near the volcanic source, ignimbrites often contain thick accumulations of lithic blocks, and distally, many show meter-thick accumulations of rounded cobbles of pumice. Ignimbrites may be white, grey, pink, beige, brown, or black depending on their composition and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tholeiitic Basalt
The tholeiitic magma series () is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma into a more evolved, silica rich end member. Rock types of the tholeiitic magma series include tholeiitic basalt, ferro-basalt, tholeiitic basaltic andesite, tholeiitic andesite, dacite and rhyolite. The variety of basalt in the series was originally called ''tholeiite'' but the International Union of Geological Sciences recommends that ''tholeiitic basalt'' be used in preference to that term.Le Maitre ''et al.'' 2002 Tholeiitic rock types tend to be more enriched in iron and less enriched in magnesium and aluminium than calc-alkaline rock types. They are thought to form in a less oxidized environment than calc-alkaline rocks. Tholeiitic basalt is formed at mid-ocean ridges and makes up much of the oceanic crust. Almost all the ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of Reykjanes Peninsula
The Reykjanes Peninsula ( ) in southwest Iceland is the continuation of the mostly submarine Reykjanes Ridge, a part of the Mid-Atlantic Ridge, on land and reaching from Esja in the north and Hengill in the east to Reykjanestá in the west. Suðurnes (transl. Southern Peninsula) is an administrative unit covering part of Reykjanes Peninsula. A great deal of volcanic activity was occurring in the Reykjanes Peninsula in 2020 and into 2024, after nearly 800 years of inactivity. After the eruption of the Fagradalsfjall volcano on 19 March 2021, National Geographic's experts predicted that this "may mark the start of decades of volcanic activity". The eruption was small leading to a prediction that this volcano was unlikely to threaten "any population centers". Origin The two most important factors for the existence of Iceland, rifting in combination with the Iceland hotspot, were responsible for the existence of Reykjanesskagi. Reykjanes Peninsula originated in a so-called ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Iceland Seismic Zone
The geological deformation of Iceland is the way that the rocks of the island of Iceland are changing due to tectonic forces. The geological deformation help to explain the location of earthquakes, volcanoes, fissures, and the shape of the island. Iceland is the largest landmass () situated on an oceanic ridge. It is an elevated plateau of the sea floor, situated at the crossing of the Mid-Atlantic Ridge and the Greenland-Iceland-Scotland ridge. It lies along an oceanic divergent plate boundary: the western part of Iceland sits on the North American Plate and the eastern part sits on the Eurasian Plate. The Reykjanes Ridge of the Mid-Atlantic ridge system in this region crosses the island from southwest and connects to the Kolbeinsey Ridge in the northeast. Iceland is geologically young: all rocks there were formed within the last 25 million years. It started forming in the Early Miocene sub-epoch, but the oldest rocks found at the surface of Iceland are from the Middle Miocene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reykjavík
Reykjavík is the Capital city, capital and largest city in Iceland. It is located in southwestern Iceland on the southern shore of Faxaflói, the Faxaflói Bay. With a latitude of 64°08′ N, the city is List of northernmost items, the world's northernmost capital of a sovereign state. Reykjavík has a population of around 139,000 as of 2025. The surrounding Capital Region (Iceland), Capital Region has a population of around 249,000, constituting around 64% of the country's population. Reykjavík is believed to be the location of the first permanent settlement in Iceland, which, according to , was established by Ingólfr Arnarson, Ingólfur Arnarson in 874 Anno Domini, AD. Until the 18th century, there was no urban development in the city location. The city was officially founded in 1786 as a trading town and grew steadily over the following decades, as it transformed into a regional and later Country, national centre of commerce, population, and governmental activities. Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Settlement Exhibition
The Settlement Exhibition Reykjavík 871±2 () is an exhibition on the settlement of Reykjavík, Iceland, created by the Reykjavik City Museum. The exhibition is based on the archaeological excavation of the ruin of one of the first houses in Iceland and findings from other excavations in the city centre. The exhibition is located in 101 Reykjavík, on Aðalstræti 16, on the corner of Aðalstræti and Suðurgata. The focus of the exhibition is the remains of a hall from the Settlement Age which was excavated in 2001. The hall was inhabited from c. 930–1000. North of the hall are two pieces of turf, remnants of a wall which was clearly built before 871±2, hence the name of the exhibition. Such precise data dating is possible because a major volcanic eruption from the Torfajökull area spread tephra across the region and this can be dated via glacial ice in Greenland. The hall is among the oldest human-made structures so far found in Iceland. Also on display are objects from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tephrochronology
250px, Tephra horizons in south-central Iceland. The thick and light coloured layer at the height of the volcanologist's hands is rhyolitic tephra from Hekla. Tephrochronology is a Geochronology, geochronological technique for dating archaeological, geological and palaeoenvironmental sequences and events by their location between upper and lower layers of tephra (volcanic ejecta) of known date, and for correlating such sequences and events at separate locations between the same layers. The premise of the technique is that each volcanic event produces a "tephra horizon", a layer of ash with a unique chemical "fingerprint" that allows the deposit to be identified across the area affected by fallout. Thus, once the volcanic event has been independently dated, the tephra horizon will act as time marker. It is a variant of the basic geological technique of stratigraphy. The main advantages of the technique are that the volcanic ash layers can be relatively easily identified in many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeology
Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts or ecofacts, archaeological site, sites, and cultural landscapes. Archaeology can be considered both a social science and a branch of the humanities. It is usually considered an independent academic discipline, but may also be classified as part of anthropology (in North America – the four-field approach), history or geography. The discipline involves Survey (archaeology), surveying, Archaeological excavation, excavation, and eventually Post excavation, analysis of data collected, to learn more about the past. In broad scope, archaeology relies on cross-disciplinary research. Archaeologists study human prehistory and history, from the development of the first stone tools at Lomekwi in East Africa 3.3 million years ago up until recent decades. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
