Changes would occur in the depositional environments and

См. также в других словарях:

• Snowball Earth — The Snowball Earth hypothesis as it was originally proposedcite book author = Kirschvink, J.L. year = 1992 chapter = Late Proterozoic low latitude global glaciation: The snowball Earth title = The Proterozoic Biosphere: A Multidisciplinary Study… …   Wikipedia

• sedimentary rock — Rock formed at or near the Earth s surface by the accumulation and lithification of fragments of preexisting rocks or by precipitation from solution at normal surface temperatures. Sedimentary rocks can be formed only where sediments are… …   Universalium

• dating — I In geology and archaeology, the process of determining an object s or event s place within a chronological scheme. Scientists may use either relative dating, in which items are sequenced on the basis of stratigraphic clues (see stratigraphy) or …   Universalium

• Australia — /aw strayl yeuh/, n. 1. a continent SE of Asia, between the Indian and the Pacific oceans. 18,438,824; 2,948,366 sq. mi. (7,636,270 sq. km). 2. Commonwealth of, a member of the Commonwealth of Nations, consisting of the federated states and… …   Universalium

• Silurian Period — Interval of geologic time, 443–417 million years ago. The third period of the Paleozoic Era, the Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appearance of land plants and jawed fishes. The continents were… …   Universalium

• geochronology — geochronologic /jee oh kron l oj ik/, geochronological, adj. geochronologist, n. /jee oh kreuh nol euh jee/, n. the chronology of the earth, as based on both absolute and relative methods of age determination. [1890 95; GEO + CHRONOLOGY] * * *… …   Universalium

• Carboniferous Period — Interval of geologic time 354–290 million years ago, marked by great changes in world geography. All the landmasses drew closer together as a result of tectonic plate movements. The supercontinent Gondwana occupied much of the Southern Hemisphere …   Universalium

• atmosphere — atmosphereless, adj. /at meuhs fear /, n., v., atmosphered, atmosphering. n. 1. the gaseous envelope surrounding the earth; the air. 2. this medium at a given place. 3. Astron. the gaseous envelope surrounding a heavenly body. 4. Chem. any… …   Universalium

• Sahara — Saharan, Saharian, adj. /seuh har euh, hair euh, hahr euh/, n. 1. a desert in N Africa, extending from the Atlantic to the Nile valley. ab. 3,500,000 sq. mi. (9,065,000 sq. km). 2. any arid waste. * * * Largest desert in the world, encompassing… …   Universalium

• river — river1 riverless, adj. riverlike, adj. /riv euhr/, n. 1. a natural stream of water of fairly large size flowing in a definite course or channel or series of diverging and converging channels. 2. a similar stream of something other than water: a… …   Universalium

• continental landform — ▪ geology Introduction       any conspicuous topographic feature on the largest land areas of the Earth. Familiar examples are mountains (including volcanic (volcanism) cones), plateaus, and valleys. (The term landform also can be applied to… …   Universalium