Some Aspects of the Steinmann Trinity, Mainly Chemical

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.