|
Microbially Induced Sedimentary Structure
Microbially induced sedimentary structures (MISS) are primary sedimentary structures formed by the interaction of microbes with sediment and physical agents of erosion, deposition, and transportation. The structures commonly form when microbial mats (which may comprise bacteria, fungi, protozoans, archaea or algae) are preserved in the sedimentary geological record. There are 17 main types of macroscopic and microscopic MISS.Noffke, N., 2010, Microbial Mats in Sandy Deposits from the Archean Era to Today: Springer Verlag, Heidelberg, 193 p. Of those, wrinkle structures and microbial mat chips are the most abundant in the fossil record. Other MISS include sinoidal structures, polygonal oscillation cracks, multidirected ripple marks, erosional remnants and pockets, or gas domes. Although these structures have only recently been named and systematically described, links between microbes and distinctive structures in sediments and sedimentary rocks have been suggested by several ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrobiology (journal)
''Astrobiology'' is a peer-reviewed scientific journal covering research on the origin, evolution, distribution and future of life across the universe. The journal's scope includes astrobiology, astrophysics, astropaleontology, bioastronomy, cosmochemistry, ecogenomics, exobiology, extremophiles, geomicrobiology, gravitational biology, life detection technology, meteoritics, origins of life, planetary geoscience, planetary protection, prebiotic chemistry, space exploration technology and terraforming. Abstracting and indexing This journal is indexed by the following services: According to the '' Journal Citation Reports'', the journal has a 2019 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 4.091. References External links * Astrobiology journals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curiosity (rover)
''Curiosity'' is a car-sized Mars rover designed to explore the Gale crater on Mars as part of NASA's Mars Science Laboratory (MSL) mission. ''Curiosity'' was launched from Cape Canaveral (CCAFS) on November 26, 2011, at 15:02:00 UTC and landed on Aeolis Palus inside Gale crater on Mars on August 6, 2012, 05:17:57 UTC. The Bradbury Landing site was less than from the center of the rover's touchdown target after a journey. Mission goals include an investigation of the Martian climate and geology, assessment of whether the selected field site inside Gale has ever offered environmental conditions favorable for microbial life (including investigation of the role of water), and planetary habitability studies in preparation for human exploration. In December 2012, ''Curiosity'' two-year mission was extended indefinitely, and on August 5, 2017, NASA celebrated the fifth anniversary of the ''Curiosity'' rover landing. On August 6, 2022, a detailed overview of accomplishme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yellowknife Bay, Mars
Yellowknife Bay is a geologic formation in Gale Crater on the planet Mars. NASA's Mars Science Laboratory rover, named ''Curiosity'', arrived at the low lying depression on December 17, 2012, 125 sols, or Martian days, into its 668-sol planned mission on the planet. Primary mission goals of the Mars Science Laboratory were to assess the potential habitability of the planet and whether or not the Martian environment is, or has ever been, capable of supporting life. The site was chosen after much study of the region by previous missions. The Mars Reconnaissance Orbiter observed morphological features created by the presence of liquid water, suggesting the presence of an ancient lake which could have sustained microbial life. The geologic depression takes its name from the city Yellowknife, capital of the Canadian Northwest Territories, in honor of the 4 billion year old rock in the region surrounding the city, which matches the approximate age of the uncovered rock in Gale Crater. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmosphere (less than 1% that of Earth's), and has a crust primarily composed of elements similar to Earth's crust, as well as a core made of iron and nickel. Mars has surface features such as impact craters, valleys, dunes and polar ice caps. It has two small and irregularly shaped moons, Phobos and Deimos. Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a large impact feature. Days and seasons on Mars are comparable to those of Earth, as the planets have a similar rotation period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agronomic Revolution
The "Cambrian substrate revolution" or "Agronomic revolution", evidenced in trace fossils, is the diversification of animal burrowing during the early Cambrian period. Before this "widening of the behavioural repertoire", bottom-dwelling animals mainly grazed on the microbial mats that lined the surface, crawling above (like how freshwater snails still do) or burrowing just below them. These microbial mats created a barrier between the water and the sediment underneath, which was less water-logged than modern sea-floors, and almost completely anoxic (lacking in oxygen). As a result, the substrate was inhabited by sulfate-reducing bacteria, whose emissions of hydrogen sulfide (H2S) made the substrate toxic to most other organisms. Around the start of the Cambrian, organisms began to burrow vertically, forming a great diversity of different fossilisable burrow forms as they penetrated the sediment for protection or to feed. These burrowing animals broke down the microbial mats, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacara Biota
The Ediacaran (; formerly Vendian) biota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period (). These were composed of enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The Ediacaran biota may have undergone evolutionary radiation in a proposed event called the Avalon explosion, . This was after the Earth had thawed from the Cryogenian period's extensive glaciation. This biota largely disappeared with the rapid increase in biodiversity known as the Cambrian explosion. Most of the currently existing body plans of animals first appeared in the fossil record of the Cambrian rather than the Ediacaran. For macroorganisms, the Cambrian biota appears to have almost completely replaced the organisms that dominated the Ediacaran fossil record, although relationships are sti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ediacaran
The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and the beginning of the Phanerozoic Eon. It is named after the Ediacara Hills of South Australia. The Ediacaran Period's status as an official geological period was ratified in 2004 by the International Union of Geological Sciences (IUGS), making it the first new geological period declared in 120 years. Although the period takes its name from the Ediacara Hills where geologist Reg Sprigg first discovered fossils of the eponymous Ediacaran biota in 1946, the type section is located in the bed of the Enorama Creek within Brachina Gorge in the Flinders Ranges of South Australia, at . The Ediacaran marks the first appearance of widespread multicellular fauna following the end of Snowball Earth glaciation events, the so-called Ediacaran bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More solar e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossils
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AP News
The Associated Press (AP) is an American non-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association. It produces news reports that are distributed to its members, U.S. newspapers and broadcasters. The AP has earned 56 Pulitzer Prizes, including 34 for photography, since the award was established in 1917. It is also known for publishing the widely used ''AP Stylebook''. By 2016, news collected by the AP was published and republished by more than 1,300 newspapers and broadcasters, English, Spanish, and Arabic. The AP operates 248 news bureaus in 99 countries. It also operates the AP Radio Network, which provides newscasts twice hourly for broadcast and satellite radio and television stations. Many newspapers and broadcasters outside the United States are AP subscribers, paying a fee to use AP material without being contributing members of the cooperative. As part of their cooperative agreement with the AP, mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Structures
Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition. Sediments and sedimentary rocks are characterized by bedding, which occurs when layers of sediment, with different particle sizes are deposited on top of each other. These beds range from millimeters to centimeters thick and can even go to meters or multiple meters thick. Sedimentary structures such as cross-bedding, graded bedding, and ripple marks are utilized in stratigraphic studies to indicate original position of strata in geologically complex terrains and understand the depositional environment of the sediment. Flow structures There are two kinds of flow structures: bidirectional (multiple directions, back-and-forth) and unidirectional. Flow regimes in single-direction (typically fluvial) flow, which at varying speeds and velocities produce different structures, are called bedforms. In the ''lower flow regime'', the natural progression is from a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Mars")
.svg "Click for more on -> Earth")
