Metasedimentary xenoliths in the lavas of the Timanfaya eruption (1730–1736, Lanzarote, Canary Islands): metamorphism and contamination processes

• DOI: 10.1017/s0016756806001713
• Publication Date: 2006-03-13T06:43:55Z
• Authors: A. APARICIO; M. A. BUSTILLO; R. GARCIA; V. ARAÑA
• Keywords: Xenolith

We report on the investigation of contact metamorphism provoked by emplacement a shallow magma chamber during Timanfaya eruption Lanzarote from 1730 to 1736 AD . The study was carried out metamorphic xenoliths basaltic lavas, and shows how primary basanitic contaminated sedimentary rocks. Mineralogical chemical studies allowed definition several xenolith types. Silica (quartz, tridymite, cristobalite or mixture these, constituting more than 50 % xenolith) calc-silicate (wollastonite, sometimes 2M type, diopside, forsterite are most frequent. Other minerals recognized were calcite, dolomite, augite, enstatite, hypersthene, spinel scapolite. mineralogy some textures forsteritic identical those found in ultrabasic (dunites) point possible origin for them. Major trace elements showed diversity composition, controlled mineralogy. REE composition is high, compared with not affected metamorphism. mineral assemblages define facies low, medium high grade, depending distance rocks border. IGPETWIN-MIXING program used verify contamination process, taking as representative sedimentary/metamorphic that melted. results indicated rock can produce tholeiitic compositions.