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Terrigenous Sediment
In oceanography, terrigenous sediments are those derived from the erosion of rocks on land; that is, they are derived from ''terrestrial'' (as opposed to marine) environments. Consisting of sand, mud, and silt carried to sea by rivers, their composition is usually related to their source rocks; deposition of these sediments is largely limited to the continental shelf. Sources of terrigenous sediments include volcanoes, weathering of rocks, wind-blown dust, grinding by glaciers, and sediment carried by rivers or icebergs. Terrigenous sediments are responsible for a significant amount of the salt in today's oceans. Over time rivers continue to carry minerals to the ocean but when water evaporates, it leaves the minerals behind. Since chlorine and sodium are not consumed by biological processes, these two elements constitute the greatest portion of dissolved minerals. Quantity Some 1.35 billion tons, or 8% of global river-borne sediment (16.5-17 billion tons globally), is tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanography
Oceanography (), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology. It is an Earth science, which covers a wide range of topics, including ocean currents, waves, and geophysical fluid dynamics; fluxes of various chemical substances and physical properties within the ocean and across its boundaries; ecosystem dynamics; and plate tectonics and seabed geology. Oceanographers draw upon a wide range of disciplines to deepen their understanding of the world’s oceans, incorporating insights from astronomy, biology, chemistry, geography, geology, hydrology, meteorology and physics. History Early history Humans first acquired knowledge of the waves and currents of the seas and oceans in pre-historic times. Observations on tides were recorded by Aristotle and Strabo in 384–322 BC. Early exploration of the oceans was primarily for cartography and mainly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Society Of America
The Geological Society of America (GSA) is a nonprofit organization dedicated to the advancement of the geosciences. History The society was founded in Ithaca, New York, in 1888 by Alexander Winchell, John J. Stevenson, Charles H. Hitchcock, John R. Procter and Edward Orton and has been headquartered at 3300 Penrose Place, Boulder, Colorado, US, since 1967. GSA began with 100 members under its first president, James Hall. In 1889 Mary Emilie Holmes became its first female member. It grew slowly but steadily to 600 members until 1931, when a nearly $4 million endowment from 1930 president R. A. F. Penrose Jr. jumpstarted GSA's growth. As of December 2017, GSA had more than 25,000 members in over 100 countries. The society has six regional sections in North America, three interdisciplinary interest groups, and eighteen specialty divisions. Activities The stated mission of GSA is "to advance geoscience research and discovery, service to society, stewardship of Ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentology
Sedimentology encompasses the study of modern sediments such as sand, silt, and clay, and the processes that result in their formation (erosion and weathering), transport, deposition and diagenesis. Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures. Sedimentary rocks cover up to 75% of the Earth's surface, record much of the Earth's history, and harbor the fossil record. Sedimentology is closely linked to stratigraphy, the study of the physical and temporal relationships between rock layers or strata. The premise that the processes affecting the earth today are the same as in the past is the basis for determining how sedimentary features in the rock record were formed. By comparing similar features today to features in the rock record—for example, by comparing modern sand dunes to dunes preserved in ancient aeolian sandstones—geologists reconstruct past environm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rocks
Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedimentation is any process that causes these particles to settle in place. Geological detritus originates 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 is 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 when dissolved minerals precipitate from water solution. The sedimentary rock cover of the continents of the Earth's crust is extensive (73% of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogenous Ooze
Biogenous ooze is marine sediment that accumulates on the seafloor and is a byproduct of the death and sink of the skeletal remains of marine organisms. Formation and composition Biogenous ooze consists of organic compounds, usually in the form of microorganism tests that fall from closer to the ocean surface to the ocean floor after death. For marine sediment to receive this classification, it must be composed of more than 30% skeletal material which also includes teeth and shells. Types of biogenous sediments The two primary types of ooze are siliceous, which is composed primarily of silica (), and calcareous or carbonate, which is mostly calcium carbonate (). In an area in which biogenous is the dominant sediment type, the composition of microorganisms in that location determines to which category it is classified. The primary types of microorganisms used to classify ooze are radiolarians and diatoms (siliceous), and coccolithophores and foraminifera (calcareous). The pres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagic Sediments
Pelagic sediment or pelagite is a fine-grained sediment that accumulates as the result of the settling of particles to the floor of the open ocean, far from land. These particles consist primarily of either the microscopic, calcareous or siliceous shells of phytoplankton or zooplankton; clay-size siliciclastic sediment; or some mixture of these, along with detritus ( marine snow) included. Trace amounts of meteoric dust and variable amounts of volcanic ash also occur within pelagic sediments. Based upon the composition of the ooze, there are three main types of pelagic sediments: siliceous oozes, calcareous oozes, and red clays.Rothwell, R.G., (2005) ''Deep Ocean Pelagic Oozes'', Vol. 5. of Selley, Richard C., L. Robin McCocks, and Ian R. Plimer, Encyclopedia of Geology, Oxford: Elsevier Limited. HüNeke, H., and T. Mulder (2011) ''Deep-Sea Sediments''. Developments in Sedimentology, vol. 63. Elsiever, New York. 849 pp. The composition of pelagic sediments is controlled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate Change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global temperatures is Scientific consensus on climate change, driven by human activities, especially fossil fuel burning since the Industrial Revolution. Fossil fuel use, Deforestation and climate change, deforestation, and some Greenhouse gas emissions from agriculture, agricultural and Environmental impact of concrete, industrial practices release greenhouse gases. These gases greenhouse effect, absorb some of the heat that the Earth Thermal radiation, radiates after it warms from sunlight, warming the lower atmosphere. Carbon dioxide, the primary gas driving global warming, Carbon dioxide in Earth's atmosphere, has increased in concentratio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology (journal)
''Geology'' is a peer-reviewed publication of the Geological Society of America (GSA). GSA stated (in 2006) (ISSN 0091-7613) that it is the most widely read scientific journal in the field of earth science. It is published monthly, with each issue containing 20 or more articles. One of the goals of the journal is to provide a forum for shorter articles (four pages each) and less focus on purely academic research–type articles. According to the ''Journal Citation Reports'', the journal had a 2020 impact factor of 5.399. The journal is indexed in Scopus and SCImago The SCImago Journal Rank (SJR) indicator is a measure of the prestige of scholarly journals that accounts for both the number of citations received by a journal and the prestige of the journals where the citations come from. Etymology SCImag .... See also * List of scientific journals ** List of earth and atmospheric sciences journals References External links *Geology — Browse Issues [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock (geology)
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the Earth's crust, crust, and most of its interior, except for the liquid Earth's outer core, outer core and pockets of magma in the asthenosphere. The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks. Igneous rocks are formed when magma cools in the Earth's crust, or lava cools on the ground surface or the seabed. Sedimentary rocks are formed by diagenesis and lithification of sediments, which in turn are formed by the weathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brahmaputra
The Brahmaputra is a trans-boundary river which flows through Southwestern China, Northeastern India, and Bangladesh. It is known as Brahmaputra or Luit in Assamese, Yarlung Tsangpo in Tibetan, the Siang/Dihang River in Arunachali, and Jamuna River in Bengali. By itself, it is the 9th largest river in the world by discharge, and the 15th longest. It originates in the Manasarovar Lake region, near Mount Kailash, on the northern side of the Himalayas in Burang County of Tibet where it is known as the Yarlung Tsangpo River. The Brahmaputra flows along southern Tibet to break through the Himalayas in great gorges (including the Yarlung Tsangpo Grand Canyon) and into Arunachal Pradesh. It enters India near the village of Gelling in Arunachal Pradesh and flows southwest through the Assam Valley as the Brahmaputra and south through Bangladesh as the Jamuna (not to be confused with the Yamuna of India). In the vast Ganges Delta, it merges with the Ganges, popularly kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ganges
The Ganges ( ; in India: Ganga, ; in Bangladesh: Padma, ). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international which goes through India, Bangladesh, Nepal and China." is a trans-boundary river of Asia which flows through India and Bangladesh. The river rises in the western Himalayas in the States and union territories of India, Indian state of Uttarakhand. It flows south and east through the Gangetic Plain, Gangetic plain of North India, receiving the right-bank tributary, the Yamuna, which also rises in the western Indian Himalayas, and several left-bank tributaries from Nepal that account for the bulk of its flow. In West Bengal state, India, a feeder canal taking off from its right bank diverts 50% of its flow southwards, artificially connecting it to the Hooghly River. The Ganges continues into Bangladesh, its name changing to the Padma River, Padma. It is then joined by the Jamuna River (Bangladesh), Jamuna, the lower str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
