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A gabbro composed principally of calcic plagioclase and olivine. Also known as forellenstein.



an igneous rock of the gabbro group, consisting mainly of basic plagioclase (labradorite or bytownite) and small amounts of olivine. Pyroxenes are either present in negligible amounts or completely absent. Serpentinization of the olivine is sometimes accompanied by the formation of characteristic fissures, which radiate from the olivine grains, in the plagioclase.

References in periodicals archive ?
Dighem airborne geophysical data suggests that the main mineralised troctolite body continues west of grid line 0 + 00 for approximately an additional 5 km.
Occurrences of major mafic-ultramafic bodies in the northern Dashwoods Subzone # (a) Location Lithology Mineralogy (b) 1 Puddle Pond Troctolite, ol-gabbro, Varying amounts of gabbro, hbl gabbro, Ol+Pl+Cpx+Hbl+Opx+/-Bt# ol-norite 2 John's Brook Gabbro, hbl-gabbro Cpx+Pl+Hbl# Lake gabbro 3 Whaleback Lherzolite, dunite, Relic Ol+Cpx+opx; Pond websterite, wehrlite, Tr+Chl+Srp+Car; Hbl+Pl# metagabbro 4 W of Silver Dunite, wehrlite, Relic O1+Cpx+Opx+Cr; Pond harzburgite, Tr+Chl+Srp+Car; Am+Chl pyroxenite, gabbro.
Stephen est constitue d'un noyau de dunite et de troctolite, entoure de strates de gabbro et de gabbro a olivine.
Stephen Gabbro consists of complexly intermingled olivine gabbro, olivine gabbronorite, and olivine norite, with less abundant gabbro, gabbronorite, norite, troctolite, anorthosite, and dunite.
The mineralization is associated with a Troctolite band at the contact between the Middle and Upper Banded Series, and although the zone is recessive it appears to be more continuous than previously thought.
The mineralisation intersected in this hole is associated with lithologies which comprise alternating bands of troctolite, melatroctolite, anorthosite and olivine gabbro.
The Properties, while almost completely overlain by the Labrador Sea, are interpreted to be underlain by the basal portion of the Kiglapait Intrusion, one of a series of troctolite intrusions belonging to the Nain Plutonic Suite.
Cartaway tested two of the PEM anomalies with three drill holes during 1996, all of which intersected a layered succession of magnetite rich troctolite and anorthosite, and two holes on the J anomaly which had up to 20 percent net-textured sulphides over 2 meters at the base of a troctolite layer.
The hole was spotted to test an audiomagnetotelluric (MT) geophysical conductor, located 700 to 1,000 metres in depth, associated with a surface mapped troctolite pluton and the western edge of an 8 mgal gravity high anomaly.
The hole intersected 412 meters of foliated/layered leuconorite and sections of layered troctolite before passing into younger anorthosite-leuconorite rocks.
Geophysical survey results support the theory that the Western Extension of the main deposit trends southwest toward a significant body of troctolite known as the Ashley Zone.
On project 10-1, numerous olivine-bearing rocks as well as troctolite dikes occur in close proximity to extensive massive sulfide mineralization.