- GLOSSARY OF VOLCANIC TERMS
Pyroclastic deposits generated by ash fall which maintain a uniform thickness and drape over all but the steepest topography (Cas and Wright, 1987, p. 96).
Glossary of volcanic terms. - University of Wisconsin Oshkosh. G. J. Hudak. 2001.
Look at other dictionaries:
Pyroclastic fall — A pyroclastic fall is a uniform deposit of material which has been ejected from an eruption or plume such as an ash fall or tuff. Pyroclastic flows occur relatively spontaneously in the geological time scale and are great indicators of time.… … Wikipedia
airfall — GLOSSARY OF VOLCANIC TERMS Volcanic ash that has fallen through the air from an eruption cloud. Airfall deposits are characteristically well sorted and well layered, and typically exhibit mantle bedding (Foxworthy and Hill, 1982; Cas and Wright,… … Glossary of volcanic terms
pyroclastic fall deposit — GLOSSARY OF VOLCANIC TERMS Volcaniclastic (pyroclastic) deposits formed from the rain out of clasts through the atmosphere from an eruption jet and/or plume during an explosive eruption (Houghton et al., 2000, p. 555). Fall deposits typically… … Glossary of volcanic terms
metamorphic rock — Any of a class of rocks that result from the alteration of preexisting rocks in response to changing geological conditions, including variations in temperature, pressure, and mechanical stress. The preexisting rocks may be igneous, sedimentary,… … Universalium
Earth Sciences — ▪ 2009 Introduction Geology and Geochemistry The theme of the 33rd International Geological Congress, which was held in Norway in August 2008, was “Earth System Science: Foundation for Sustainable Development.” It was attended by nearly… … Universalium
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
Olympic-Wallowa Lineament — Location of the Olympic Wallowa Lineament. Is the OWL an optical illusion? The Olympic Wallowa lineament (OWL) – first reported by cartographer Erwin Raisz in 1945  on a relief map of the continental United States – is a physiographic feature… … Wikipedia
Geology of the Iberian Peninsula — The geology of the Iberian Peninsula consists of the study of the rock formations on the Iberian Peninsula, which includes Spain, Portugal, Andorra, and Gibraltar. The peninsula contains rocks from every age from Ediacaran to Recent, and almost… … Wikipedia
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
Precambrian time — Interval of geologic time from с 3. 8 billion years ago, the age of the oldest known rocks, to 544 million years ago, the beginning of the Cambrian Period. This interval represents more than 80% of the geologic record and thus provides important… … Universalium