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Vocabulary. Oceanography is the study of the physical, chemical, and biological features of the ocean, including the ocean’s ancient history, its current condition, and its future. In a time when the ocean is threatened by climate change and pollution, coastlines are eroding, and entire species of marine life are at risk of extinction, the ...In geology, lamination (from Latin lāmina 'thin layer') is a small-scale sequence of fine layers ( PL: laminae; SG: lamina) that occurs in sedimentary rocks. Laminae are normally smaller and less pronounced than bedding. Lamination is often regarded as planar structures one centimetre or less in thickness, whereas bedding layers are greater ...Geologic time scale. Diagram of geological time scale as a spiral. Geologic time scale uses the principles and techniques of geology to work out the geological history of the Earth. [1] It looks at the processes which change the Earth's surface and rocks under the surface. Geologists use stratigraphy and paleontology to find out the sequence of ...The geologic time scale is the "calendar" for events in Earth history. It subdivides all time into named units of abstract time called—in descending order of duration— eons, eras, periods, epochs, and ages.The enumeration of those geologic time units is based on stratigraphy, which is the correlation and classification of rock strata. The fossil forms that occur in the rocks, however ...supercontinent, large landmass that accounts for the vast majority of Earth’s land. Some researchers argue that the threshold for a landmass to be considered a supercontinent is approximately 75 percent of Earth’s continental crust, whereas others note that a supercontinent must be made up of most or all of the world’s existing …Charles Lyell. Sir Charles Lyell, 1st Baronet, FRS (14 November 1797 – 22 February 1875) was a Scottish geologist who demonstrated the power of known natural causes in explaining the earth's history. He is best known today for his association with Charles Darwin and as the author of Principles of Geology (1830–33), which presented to a wide ...Inland sea. An inland sea (also known as an epeiric sea or an epicontinental sea) is a continental body of water which is very large in area and is either completely surrounded by dry land or connected to an ocean by a river, strait or "arm of the sea". An inland sea will generally have higher salinity than a freshwater lake, but usually lower ...An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth. Comparable terms are epoch, age, period, saeculum, aeon (Greek aion) and Sanskrit yuga.Stratigraphy, scientific discipline concerned with the description of rock successions and their interpretation in terms of a general time scale. It provides a basis for historical geology, and its principles and methods have found application in such fields as petroleum geology and archaeology.Deep time is not an abstract, distant prospect, but a spectral presence in the everyday. The irony of the Anthropocene is that we are conjuring ourselves as ghosts that will haunt the very deep ...Although the term aeon may be used in reference to a period of a billion years (especially in geology, cosmology and astronomy), its more common usage is for any long, indefinite period. Aeon can also refer to the four aeons on the geologic time scale that make up the Earth's history, the Hadean , Archean , Proterozoic , and the current aeon, Phanerozoic .Era definition, a period of time marked by distinctive character, events, etc.: The use of steam for power marked the beginning of an era. See more. An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth.Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms.It occurs when the rate of extinction increases with respect to the background extinction rate and the rate of speciation.Two or more periods comprise a geological Era. Two or more Eras form an Eon, the largest division of geologic time. Some periods are divided into epochs. The ...An ice age is a long period of reduction in the temperature of the Earth's surface and atmosphere. Ice Age may also refer to: Science. Last Glacial Period, the most recent glacial period (115,000 to 11,700 years ago) Late Cenozoic Ice Age, the geologic period of the last 33.9 million years Epoch, unit of geological time during which a rock series is deposited. It is a subdivision of a geological period, and the word is capitalized when employed in a formal sense (e.g., …The geological time scale is one of the crowning achievements of science in general and geology in particular. ... The most well known of all geological periods is the Jurassic period of the Mesozoic era (the movie Jurassic Park, ... as well as debate about what characteristics should define its beginning.Cenozoic Era, third of the major eras of Earth’s history, beginning about 66 million years ago and extending to the present. It was the interval of time during which the continents assumed their modern configuration and geographic positions and during which Earth’s flora and fauna evolved toward those of the present.The room had the elegance of a bygone era. We live in an era of religious uncertainty. a new era in the history of art; a practice that has survived into the present era; movies of the silent era; the early centuries of the Christian Era; the golden era of radio; In the modern era, the state is the provider of welfare. The meaning of ERA is a fixed point in time from which a series of years is reckoned. How to use era in a sentence. Synonym Discussion of Era.The Precambrian is the earliest of the geologic ages, which are marked by different layers of sedimentary rock. ... era. Photograph by Joel Sartore, National ...

A passive margin is the transition between oceanic and continental lithosphere that is not an active plate margin. A passive margin forms by sedimentation above an ancient rift, now marked by transitional lithosphere. Continental rifting forms new ocean basins. Eventually the continental rift forms a mid-ocean ridge and the locus of extension ...Greywacke is variation of sandstone that saperate from other to hardness, dark color, and poorly sorted angular grains of quartz and feldspar..It is a textural immature sedimentary rock found in the Paleozoic layers. Larger grains can be from sand to pebble length, and matrix materials are in the order of 15% by volume of rocks.A deep color …The geologic time scale is divided into eons, eras, periods, epochs, and ages. Our activities, and the time scale for download above, focus primarily on two of those divisions most relevant for an introduction to geologic time: eras and periods. The beginning and end of each chunk of time in the geologic time scale is determined by when some ...An unconformity are contact between two rock units. Unconformities are typically buried erosional surfaces that can represent a break in the geologic record of hundreds of millions of years or more. It called an unconformity because the ages of the layers of rock that are abutting each other are discontinuous. An expected age of layer or …Like the periodic table, the Geologic time scale is one of those amazing human endeavours to turn a vast amount of evidence from astronomy, rocks, fossils, history and politics into a nifty little ...

Eons may be further divided into smaller chunks called eras, and each era is divided into periods. Figure 12.1 shows you what the geologic time scale looks like ...(2004,. 2005), while officially sanctioned by neither the Interna- tional Commission on Stratigraphy (ICS) nor the Inter- national Union of Geological Sciences ...…

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs. sill, also called sheet, flat intrusion of igneo. Possible cause: An ice age is a long period of reduction in the temperature of the Earth's surface a.