Some Aspects of the Steinmann Trinity, Mainly Chemical

Abstract

Attention is directed to Eskola, Vuoristo & Rankama's (1935) experimental reaction development of albite from anorthite ; to the importance of depth of immersion in relation to such spilitic change ; to Vuagnat's investigation of textural and chemical zoning within individual pillows; to crystallizations that have occurred in a Ligurian variolitic ash, dated with reference to contact with the sea and subsequent explosion; to frequent occurrence of penecontemporaneous gabbro fragments in other Ligurian ashes, where the gabbro is often in the condition of augen-gabbro ; to a parent gabbro that illustrates both the shear and shatter phenomena involved ; to the condition of lavas within the Mull pneumatolytic zone and crater-lake as compared with that of geosynclinal suites elsewhere ; to Benson's Australasian pillowlavas, some of which show little change of composition ; to Campbell and Lunn's Dalmahoy dolerite, Edinburgh, of mugearitic composition, associated with Auchinoon dolerite, of spilitic composition ; and to the strong support which much of the above furnishes to Dewey and Flett's conclusion that many submarine lavas have suffered considerable chemical change while cooling. The behaviour of Ligurian gabbros (and serpentinites) raises other points of interest in relation to the Steinmann trinity.

Ophicalcites from the northern Pyrenean belt: a field, petrographic and stable isotope study

“…Because of the wide variety of ophicalcites and their occurrence in different oceanic or continental margin settings, it is important to recall that the term ophicalcite does not refer to a genetic process, but to a generic rock-type. Among the processes invoked for their formation one group refers to endogenic evolution, involving various deep seated phenomena such as: (1) mantle originated gas seeps (Bonatti et al 1974;Haggerty 1991;Kelemen et al 2004); (2) magmatic intrusions (Cornelius 1912;Bailey & McCallien 1960); (3) contact and regional metamorphism (Peters 1965;Trommsdorff et al 1980) and (4) hydrothermal fluidinteractions (Cornelius 1912;Lavoie & Cousineau 1995;Artemyev & Zaykov 2010). Another group refers to surficial processes involving mechanical mixing of carbonates and ultramafic rocks through tectonic crushing, sedimentary reworking and gravity-driven infilling of veins and fractures Knipper 1978;Bernoulli & Weissert 1985;Früh-Green et al 1990;Treves & Harper 1994;Treves et al 1995;Knipper & Sharas'kin 1998).…”

Petrography and Mapping of the Gwal Melange of Khanozai Region, Balochistan, Pakistan

“…Their origin is still probed as endogenic and surficial by the different schools of thought. The group preferring their evolution as endogenic divides it as (1) gas seeps originated by mantle, (2) intruded magma, (3) regional and contact metamorphism related, and (4) hydrothermally interacted fluid [38][39][40][41][42][43][44][45][46]. Another school of thought describes ophicarbonates origin as a surficial process where ultramafic and carbonates are mixed through processes of gravity, tectonic crushing and/or sedimentary reworking [47][48][49][50][51][52][53][54].…”

Ancient oceans and continental margins of the Alpine‐Mediterranean Tethys: deciphering clues from Mesozoic pelagic sediments and ophiolites

“…, 2003). In the past, various interpretations of these breccias have been offered, ranging from products of contact metamorphism (Steinmann, 1905, 1913) to magmatic carbonatites (Bailey & McCallien, 1960) and subaerial caliche (Folk and McBride, 1976, 1978). However, new observations indicate that these breccias are the product of a combination of tectonic fracturing, replacement of serpentine minerals by calcite, sea floor carbonate cementation and infill by pelagic and/or diagenetic sediment (Fig.…”