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Bengal Basin
The Bengal Basin is a sedimentary basin. The term Bengal basin is used to describe geological structure of Bengal region's sedimentary basin. It is spread across the Indian states of West Bengal and Bangladesh. The Bengal basin in the eastern part of the Indian subcontinent forms the world's largest fluvio-delta and shallow marine sedimentary basin. This shallow marine sedimentary basin coupled with the Bengal Fan beneath the Bay of Bengal to form the largest sedimentary dispersal system known in the modern world. The Bengal basin was initiated during the breakup of Gondwanaland in the late Mesozoic Era. The basin consists of a thick Early Cretaceous-Holocene sedimentary succession. Proximal deposition of a portion of orogenic sediments from the Eastern Himalaya and Indo-Burman ranges deposited in the Bengal Basin. The thickest sediments in the basin occur in the coastal area of the Bay of Bengal, where sediments are about 20 km thick. It is bounded by faults on all its sides exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand. One such example of this is aragonite, which has been created over the past 500million years by various forms of life, such as coral and shellfish. It is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years, as in the Caribbean. Somewhat more rarely, sand may be composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar, because they are the most resistant minerals to the weathering processes at the Earth's surface. Like uncemented sand, sandstone may be imparted any color by impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Because sandstone beds can form highly visible cliffs and other topography, topographic features, certain colors of sandstone have become strongly identified with certain regions, such as the red rock deserts of Arches National Park and other areas of the Southwestern United States, American Southwest. Rock formations composed of sandstone usually allow the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.Blatt, Harvey and Robert J. Tracy (1996) ''Petrology: Igneous, Sedimentary and Metamorphic'', 2nd ed., Freeman, pp. 281–292 Shale is characterized by its tendency to split into thin layers (Lamination (geology), laminae) less than one centimeter in thickness. This property is called ''Fissility (geology), fissility''. Shale is the most common sedimentary rock. The term ''shale'' is sometimes applied more broadly, as essentially a synonym for mudrock, rather than in the narrower sense of clay-rich fissile mudrock. Texture Shale typically exhibits varying degrees of fissility. Because of the parallel orientation of clay mineral flakes in shale, it breaks in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science), crystal forms of calcium carbonate . Limestone forms when these minerals Precipitation (chemistry), precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly Dolomite (rock), dolomite, a closely related rock, which contains a high percentage of the mineral Dolomite (mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, W. H. Freeman, 2nd ed, 529 pp. The term ''mudstone'' is also used to describe carbonate rocks (limestone or dolomite) that are composed predominantly of carbonate mud. However, in most contexts, the term refers to siliciclastic mudstone, composed mostly of silicate minerals. The NASA Curiosity rover has found deposits of mudstone on Mars that contain organic substances such as propane, benzene and toluene. Definition There is not a single definition of mudstone that has gained general acceptance,Boggs 2006, p.143 though there is wide agreement that mudstones are fine-grained sedimentary rocks, composed mostly of silicate grains with a grain size less than . Individual grains this size are too small to be distinguished without a micros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hooghly River
The Hooghly River (, also spelled ''Hoogli'' or ''Hugli'') is the westernmost distributary of the Ganges, situated in West Bengal, India. It is known in its upper reaches as the Bhagirathi. The Bhagirathi splits off from the main branch of the Ganges at Giria, India, Giria. A short distance west, it meets the man-made Farakka Feeder Canal, which massively increases its flow. The river then flows south to join the Jalangi River, Jalangi at Nabadwip, where it becomes the Hooghly proper. The Hooghly continues southwards, passing through the metropolis of Kolkata. Thereafter, it empties into the Bay of Bengal. Its tributaries include the Ajay River, Ajay, Damodar River, Damodar, Rupnarayan River, Rupnarayan, and Haldi River, Haldi. The Hooghly has religious significance as Hinduism, Hindus consider the river sacred. It also plays a major role in the agriculture, industry, and climate of the state. Course The vast majority of the water that flows into the Hooghly River is provided ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rajmahal Hills
The Rajmahal Hills are located in the Santhal Pargana division of Jharkhand, India. They were located on the northern margin of the Gondwana supercontinent, and its hills are today inhabited by the Sauria Paharia people whilst its valleys are dominated by the Santhal people. The hills span over an area of . Volcanic activity during the Jurassic resulted in the formation of the Rajmahal Traps. The hills are approximately located at . The Rajmahal hills are named after the town of Rajmahal which lies in the eastern Jharkhand. The hills trend north-south with an average elevation of , from the Sahibganj district to the Dumka district. The River Ganges wanders around the hills changing the direction of flow from east to south. Francis Buchanan-Hamilton travelled through the Rajmahal hills in the early 19th century. He described the hills that seemed impenetrable in a zone where few travellers had been. He wrote that everywhere people were hostile, apprehensive of officials and unw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kolkata
Kolkata, also known as Calcutta ( its official name until 2001), is the capital and largest city of the Indian state of West Bengal. It lies on the eastern bank of the Hooghly River, west of the border with Bangladesh. It is the primary financial and commercial centre of eastern and northeastern India. Kolkata is the seventh most populous city in India with an estimated city proper population of 4.5 million (0.45 crore) while its metropolitan region Kolkata Metropolitan Area is the third most populous metropolitan region of India with a metro population of over 15 million (1.5 crore). Kolkata is regarded by many sources as the cultural capital of India and a historically and culturally significant city in the historic region of Bengal.————— The three villages that predated Calcutta were ruled by the Nawab of Bengal under Mughal suzerainty. After the Nawab granted the East India Company a trading license in 1690, the area was developed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 Megaannum#SI prefix multipliers, Ma to 100.5 Ma. Geology Proposals for the exact age of the Barremian–Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining Anoxic event#Cretaceous, early Aptian Oceanic Anoxic Event 1a (OAE1a) was dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java Plateau, Ontong Java-Manihiki Plateau, Manihiki-Hikurangi Plateau, Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Onto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midnapore District
Midnapore (Pron: mad̪aːniːpur), or sometimes Medinipur, is a former district in the Indian state of West Bengal, headquartered in Midnapore. On 1 January 2002, the district was bifurcated into two separate districts namely Purba Medinipur and Paschim Medinipur. It was the largest district of West Bengal by area and population at the time of bifurcation. Etymology There are conflicting accounts of how the name Medinipur came to be. One account claims that Medinipur was named after a local deity "Medinimata" (literally "mother of the world", a Shakti incarnation). According to Sri Hari Sadhan Das, the district got its name from "Medinikar", the founder of the city in 1238, who was the son of "Prankara", the feudal king of "Gondichadesh". He was also the writer of "Medinikosh". Hara Prasad Shastri thinks that the city Medinikar established it around the time he wrote the book (1200-1431). He is said to have built the fort called "Kornelgola" situated in the city. History Me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
