Alteration Patterns In Volcanic Rocks Within An East-West Traverse Through Central Nicaragua
Journal Article: Alteration Patterns In Volcanic Rocks Within An East-West Traverse Through Central Nicaragua
AbstractThe volcanic rocks investigated in a cross-section between the Pacific and Atlantic coasts of Nicaragua - with the exception of Recent and some Pleistocene lavas - are incipiently to strongly altered. Alteration patterns on different scales can be discerned in the Tertiary sequences: (i) a regional burial diagenesis or very low-grade burial metamorphism at the low-temperature end of the zeolite facies (mordenite subfacies) with an inferred thermal gradient of < 50°C/km, grading into (ii) a geothermal field type of alteration in mining districts (laumontite subfacies with local transition to wairakite subfacies at depth); the thermal gradient probably exceeded 100°C/km. There are also (iii) local alteration aureoles around gold-bearing quartz veins. The regional alteration assemblages include minerals that, under favorable conditions, might have formed deposits of great potential use as non-metallic raw materials (zeolites and bentonite). Mineralogical differences between the alteration outside and within mining districts might be used as an exploration guide.
- M. Darce, B. Levi, J. O. Nystrom and B. Troeng
- Published Journal
- Journal of South American Earth Sciences, 1989
M. Darce,B. Levi,J. O. Nystrom,B. Troeng. 1989. Alteration Patterns In Volcanic Rocks Within An East-West Traverse Through Central Nicaragua. Journal of South American Earth Sciences. (!) .