Geology and petrology of the potassic and ultrapotassic rocks from the northern part of Senirkent (Isparta-SW Turkey): evidence of magma–carbonate wall-rock interactions

Abstract

Potassic, ultrapotassic lava domes, flows, and volcano-sedimentary deposits including leucite-bearing and leucite-free grains crop out to the north of Senirkent (Isparta), at the apex of the Isparta Angle (southwestern Turkey). Ultrapotassic rocks are nepheline-foidolite, italite, leucitite, melilite leucitite, melilite-gehlenite leucitite, diopside leucitite, and leucitophyre with lowest SiO2 content (38.71–44.72 wt%, but the leucitophyre has 51.4 wt%), higher K2O (4.36–10.19 wt%), MgO (3.25–6.98 wt%), and K2O/Na2O ratio (2.65–32.8). Potassic rocks are phonolitic leucitites, sanidine-phyric phonolite, and trachytes with SiO2 (49.35–64.46 wt%), K2O (8.28–11.38 wt%), MgO (0.17–1.39 wt%), and K2O/Na2O ratio (2.25–11.8). Some leucitites, diopside leucitites, and phonolitic leucitites enclose partly carbonatite occurences or associated with carbonate-rich part including carbonatite globules, phlogopite, clinopyroxene, and/or leucite, melanite crystals embedded in glassy volcanic matrix and/or carbonate matrix. Primitive mantle-normalized incompatible element patterns display strong enrichments in LILEs (Cs, Rb, Ba, U, Th, Sr) relative to HFSEs (Nb, Ti) with distinct negative Nb–Ti anomalies, suggesting subduction-related lavas. Chondrite-normalized REE patterns are characterized by light REE enrichment (251–493 times chondrite for La) and flat heavy REE patterns (10–27 times chondrite for Yb). All the leucite-bearing and leucite-free rocks display similar, subparallel chondrite-normalized and primitive mantle-normalized trace element patterns, suggesting cogenetic origin. Mineralogical, petrological, and geochemical data suggest magma–carbonate wall-rock interaction and tapping of different parts of the melts within the magma chamber along the fault lines formed during neotectonic period and extension-related block faulting.