|
Porcellanite
Porcellanite or ''porcelanite'', is a hard, dense Rock (geology), rock somewhat similar in appearance to unglazed porcelain. It is often an impure variety of chert containing clay and calcareous matter. Porcellanite has been found, for example, in Northern Ireland, Poland and the Czech Republic. Tievebulliagh At Tievebulliagh, Northern Ireland, porcellanite is a tough contact metamorphism, contact metamorphosed hornfels formed from a lateritic soil horizon within a basaltic intrusive/extrusive sequence. The rock is black to dark grey in colour. Tievebulliagh is the site of a Neolithic axe or stone tool quarry, and there is another quarry on Rathlin Island. It is likely that roughouts or roughly-shaped prehistoric tools (Celt (tool), celts) were chipped on site before transportation both within Ireland and over the Irish Sea to Britain. It is also likely that the final polish would have been performed near the site of use in cutting vegetation and trees. It was commonly polished ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tievebulliagh
Tievebulliagh () is a mountain in the Glens of Antrim, Northern Ireland. It forms part of the watershed between Glenaan to the north and Glenballyemon to the south. It is situated about 4.4 km from Cushendall. Geology Tievebulliagh is formed from a volcanic plug, the intense heat generated by molten basalt has given rise to the formation of a durable flint, porcellanite, which is found at the foot of the eastern scree slope of the mountain. Three small outcrops of porcellanite can be seen on the higher south-east slope. Archaeology Evidence has been discovered of a Neolithic axe quarry at the foot of Tievebulliagh. Flint axe heads fashioned from porcellanite that originate from this quarry have been found across the British Isles, from the Outer Hebrides to the south coast of England and across the rest of Ireland. The site compares with the Langdale axe industry based in the English Lake District and the quarries at Penmaenmawr in North Wales, where large num ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basaltic
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying. Flood basalts are thick sequence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphic Rocks
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causing profound physical or chemical changes. During this process, the rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous, sedimentary, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture. They may be formed simply by being deeply buried beneath the Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and distort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a precipitation (chemistry), chemical precipitate or a diagenesis, diagenetic replacement, as in petrified wood. Chert is typically composed of the petrified remains of siliceous ooze, the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of diatoms, Dictyochales, silicoflagellates, and radiolarians. Precambrian cherts are notable for the presence of fossil cyanobacteria. In addition to Micropaleontology, microfossils, chert occasionally contains macrofossils. However, some chert is devoid of any fossils. Chert varies greatly in color (from white to black), but most often manifests as gray, brown, grayish brown and light green to rusty redW.L. Roberts, T.J. Campbell, G.R. Rapp Jr. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rocks
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies (marine snow). Sedimentation may also occur as dissolved minerals precipitate from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irish Sea
The Irish Sea or , gv, Y Keayn Yernagh, sco, Erse Sie, gd, Muir Èireann , Ulster-Scots: ''Airish Sea'', cy, Môr Iwerddon . is an extensive body of water that separates the islands of Ireland and Great Britain. It is linked to the Celtic Sea in the south by St George's Channel and to the Inner Seas off the West Coast of Scotland in the north by the North Channel. Anglesey, North Wales, is the largest island in the Irish Sea, followed by the Isle of Man. The term ''Manx Sea'' may occasionally be encountered ( cy, Môr Manaw, ga, Muir Meann gv, Mooir Vannin, gd, Muir Mhanainn). On its shoreline are Scotland to the north, England to the east, Wales to the southeast, Northern Ireland and the Republic of Ireland to the west. The Irish Sea is of significant economic importance to regional trade, shipping and transport, as well as fishing and power generation in the form of wind power and nuclear power plants. Annual traffic between Great Britain and Ireland amounts t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Great Britain and Ireland), North Channel, the Irish Sea, and St George's Channel. Ireland is the List of islands of the British Isles, second-largest island of the British Isles, the List of European islands by area, third-largest in Europe, and the List of islands by area, twentieth-largest on Earth. Geopolitically, Ireland is divided between the Republic of Ireland (officially Names of the Irish state, named Ireland), which covers five-sixths of the island, and Northern Ireland, which is part of the United Kingdom. As of 2022, the Irish population analysis, population of the entire island is just over 7 million, with 5.1 million living in the Republic of Ireland and 1.9 million in Northern Ireland, ranking it the List of European islan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celt (tool)
In archaeology, a celt is a long, thin, prehistoric, stone or bronze tool similar to an adze, hoe, or axe. A shoe-last celt was a polished stone tool used during the early European Neolithic for felling trees and woodworking. Etymology The term "celt" seems to have come about from a copyist's error in many medieval manuscript copies of Job 19:24 in the Latin Vulgate Bible, which became enshrined in the authoritative Sixto-Clementine printed edition of 1592. Where all earlier versions (the Codex Amiatinus, for example) have ''vel certe'' (the Latin for 'but surely'), the Sixto-Clementine has ''vel celte''. The Hebrew has לעד (''lā‘aḏ'') at this point, which means 'forever'. The editors of the Oxford English Dictionary " nclineto the belief that ''celtis'' was a phantom word," simply a misspelling of ''certe''. However, some scholars over the years have treated ''celtis'' as a real Latin word. From the context of Job 19:24 ("Oh, that my words were inscribed with an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rathlin Island
Rathlin Island ( ga, Reachlainn, ; Local Irish dialect: ''Reachraidh'', ; Scots: ''Racherie'') is an island and civil parish off the coast of County Antrim (of which it is part) in Northern Ireland. It is Northern Ireland's northernmost point. Geography Rathlin is the only inhabited offshore island of Northern Ireland, with a steadily growing population of approximately 150 people, and is the most northerly inhabited island off the coast of the island of Ireland. The reverse-L-shaped Rathlin Island is from east to west, and from north to south. The highest point on the island is Slieveard, above sea level. Rathlin is from the Mull of Kintyre, the southern tip of Scotland's Kintyre peninsula. It is part of the Causeway Coast and Glens council area, and is represented by the Rathlin Development & Community Association. Townland Rathlin is part of the traditional barony of Cary (around the town of Ballycastle), and of current district Moyle. The island constitutes a civ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Porcellanite")
Saunders_Quarry-1.jpg "Click for more on -> Sandstone")
