noun, (used with a plural verb)
clastic volcanic material, as scoria, dust, etc., ejected during an eruption.
(mainly US) solid matter ejected during a volcanic eruption
Solid matter, such as ash, dust, and cinders, that is ejected into the air by an erupting volcano. Tephra is a general term for all pyroclastic materials ejected from a volcano.
noun, Petrography. 1. a basaltic rock consisting essentially of pyroxene and plagioclase with nepheline or leucite. noun 1. a variety of basalt containing plagioclase, augite, and a feldspathoid, commonly nepheline, or leucite
[tef-roh-kruh-nol-uh-jee] /ˌtɛf roʊ krəˈnɒl ə dʒi/ noun, Geology. 1. a geochronologic technique based on the dating of layers of volcanic ash.
noun 1. a mineral, silicate of manganese, Mn 2 SiO 4 , occurring in orthorhombic crystals.
noun 1. a city in and the capital of Nayarit, W central Mexico. noun 1. a state in W Mexico. 10,442 sq. mi. (27,045 sq. km). Capital: Tepic. noun 1. a city in W central Mexico, capital of Nayarit state: agricultural, trading and processing centre. Pop: 341 000 (2005 est) noun 1. a state of […]