Search results
Results from the WOW.Com Content Network
Breccia is composed of coarse rock fragments held together by cement or a fine-grained matrix. [5] Like conglomerate, breccia contains at least 30 percent of gravel-sized particles (particles over 2mm in size), but it is distinguished from conglomerate because the rock fragments have sharp edges that have not been worn down. [6]
Volcanogenic massive sulfide ore deposit at Kidd Mine, Timmins, Ontario, Canada, formed 2.7 billion years ago on an ancient seafloor A cross-section of a typical volcanogenic massive sulfide (VMS) ore deposit as seen in the sedimentary record [1]
Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, [1] [2] is an opaque, [3] impure variety of silica, usually red, yellow, brown or green in color; and rarely blue.
Agate (/ ˈ æ ɡ ɪ t / AG-it) is a variety of chalcedony, [1] which comes in a wide variety of colors. Agates are primarily formed within volcanic and metamorphic rocks.The ornamental use of agate was common in ancient Greece, in assorted jewelry and in the seal stones of Greek warriors, [2] while bead necklaces with pierced and polished agate date back to the 3rd millennium BCE in the Indus ...
Iron oxide copper gold (IOCG) deposits are considered to be metasomatic expressions of large crustal-scale alteration events driven by intrusive activity. The deposit type was first recognised by discovery and study of the supergiant Olympic Dam copper-gold-uranium deposit (Olympic Dam mine), and South American examples.
Agate is distinctly banded chalcedony with successive layers differing in color or value. [66] Onyx is a banded agate with layers in parallel lines, often black and white (sardonyx). [67] Magadi-type chert is a variety that forms from a sodium silicate precursor in highly alkaline lakes such as Lake Magadi in Kenya. [68]
A Baraboo Quartzite sample, in breccia form. The brecciated purple portions are quartzite, and the matrix is white quartz A sample of Baraboo Quartzite.. Baraboo Quartzite is a Precambrian geological formation [1] of quartzite, found in the region of Baraboo, Wisconsin.
Turritella agate; This page was last edited on 30 May 2016, at 11:25 (UTC). Text is available under the Creative Commons Attribution-ShareAlike 4. ...