Alteration Patterns In Volcanic Rocks Within An East-West Traverse Through Central Nicaragua

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Journal Article: Alteration Patterns In Volcanic Rocks Within An East-West Traverse Through Central Nicaragua

Abstract
The 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.

Authors 
M. Darce, B. Levi, J. O. Nystrom and B. Troeng








Published Journal 
Journal of South American Earth Sciences, 1989





DOI 
10.1016/0895-9811(89)90043-6


 

Citation

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. (!) .