Zeolite Minerals from the North Shore of the Minas Basin, Nova Scotia Georgia Pe-Piper and Lisa Miller
Atlantic Geology 11 Zeolite minerals from the North Shore of the Minas Basin, Nova Scotia Georgia Pe-Piper and Lisa Miller Department of Geology, Saint Mary’s University, Halifax, Nova Scotia, B3H 3C3, Canada Date received: August 9, 2002 ¶ Date accepted: December 2, 2002 ABSTRACT X-ray diffraction and electron microprobe analyses show the following assemblages to be present in basalt fl ows and overlying siliciclastic sedimentary rocks along the North Shore of the Minas Basin: Five Islands – chabazite and stilbite are dominant, also “heulandite” and bar- rerite; Two Islands – analcime is dominant, gmelinite, chabazite, stilbite, and natrolite; Wasson Bluff – chabazite, stilbite and “heulandite” are dominant, also herschelite, barrerite, stellerite, analcime, wairakite, natrolite, clinoptilolite, and thomsonite; Partridge Island – chabazite and stilbite are dominant, also analcime, epistilbite, natrolite, barrerite, and “heulandite”; Cape Sharp – chabazite, stilbite, barrerite, stellerite, and “heulandite”; Horseshoe Cove – “heulandite” and stilbite; Western Cape d’Or – analcime, stilbite, natrolite, and mesolite are domi- nant, also stellerite, ?epistilbite, barrerite, scolecite, chabazite, “heulandite”, wairakite, tetranatrolite and laumontite. Comparison is made with assemblages at Arlington Quarry on North Mountain, where the dominant zeolite minerals are heulandite (sensu stricto) and stilbite. Elsewhere on North Mountain, mordenite, natrolite, and laumontite have been confi rmed. Chemical composition of hydrothermal fl uids was likely different between North Mountain and the North Shore, with fl uids in the latter area less sodic. The temperature of zeolite crystal- lization appears to have been high at Arlington Quarry, where “heulandite” and stilbite crystallised with little Na in their crystal structure. With falling temperature the crystallizing solution became enriched in Na, and sodic zeolite minerals, such as natrolite, began to crystallize.
[Show full text]