- 行业: Mining
- Number of terms: 33118
- Number of blossaries: 0
- Company Profile:
The U.S. Bureau of Mines (USBM) was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.
Founded on May 16, 1910, through the Organic Act (Public Law 179), USBM's missions ...
Said of strata and structures that dip radially outward from, or inward toward, a center, to form a dome or a basin. Compare: quaquaversal; centroclinal.
Industry:Mining
Said of strata and structures that dip toward a common center. Ant: quaquaversal. Compare: periclinal
Industry:Mining
Said of strata or stratification exhibiting the relation of unconformity to the older underlying rocks; not succeeding the underlying rocks in immediate order of age or not fitting together with them as parts of a continuous whole. In the strict sense, the term is applied to younger strata that do not conform in position or that do not have the same dip and strike as those of the immediately underlying rocks. Also, said of the contact between unconformable rocks. Compare: conformable
Industry:Mining
Said of the banded structure of certain extrusive rocks, which results in a streaked or blotched appearance. Also, said of a rock exhibiting such structure, e.g., a eutaxite. The bands or lenses were originally ejected as individual portions of magmas, were drawn out in a viscous state, and formed a heterogeneous mass in response to welding.
Industry:Mining
Said of the contact between the wall of a vein and the mineral deposit filling it, in which the vein material adheres closely to the wall; also, said of the vein material and of the wall.
Industry:Mining
Said of the graphic texture of an igneous rock that is distinguishable only with the aid of a microscope; also, said of a rock having such texture.
Industry:Mining
Said of the holocrystalline-porphyritic texture exhibited by lamprophyres, in which phenocrysts of mafic minerals are contained in a fine-grained crystalline groundmass.
Industry:Mining
Said of the irregular polygonal pattern of internal cracks developed in septaria, closely resembling the desiccation structure of mud cracks; also said of the epigenetic mineral deposits that may occur as fillings of these cracks.
Industry:Mining
Said of the mineral grains of a rock that have been regenerated by zones of secondary growth in crystalline continuity. The new material may have been deposited from solutions or from molten fluids.
Industry:Mining
