Zircon trace element geochemistry and Ti‐in‐zircon thermometry of the Linté Pan‐African granitoids, Central Cameroon: Constraints on the genesis of host magma and tectonic implications

Abstract

The Linté area belongs to the central part of the Adamawa‐Yadé Domain (AYD) within the Pan‐African Central African Fold Belt (CAFB) in Cameroon. This area is dominated by Neoproterozoic high‐K calc‐alkaline syenite and monzonite intruding Archean to Palaeoproterozoic gneisses. In this contribution, trace element compositions of zircon obtained using laser ablation inductively coupled plasma mass spectrometry are used to constrain the petrogenesis and tectonic setting of Linté area. The analysed zircon grains display restricted ranges of Hf contents with an average of 8,197 ppm in syenite, 8,220 ppm in alkali‐feldspar syenite, and 9,026 ppm in monzonite. They display high Th/U ratios (>0.5) typical of magmatic zircons. The monzonite zircons have a higher ∑REE content (483.42 ppm) than the syenite zircons (237.70 ppm). The chondrite‐normalized rare‐earth element (REE) diagram of Linté samples shows very similar patterns, characterized by a steeply rising slope due to important heavy rare‐earth element enrichment relative to light rare‐earth element, with distinctive positive Ce and negative Eu anomalies. The application of the Ti‐in‐zircon thermometer reveals a wide range of crystallization temperatures (574–1,137°C for syenites and 713–1,008°C for monzonite), implying a deep level of melting, likely within the lower continental crust of the CAFB. The integration of geochemical behaviours of some trace elements (U, Hf, Zr, Ce, Th, and Nb), together with discrimination diagrams, suggests the crystallization of a continental crust‐derived magma under variable oxidation states and emplacement in a magmatic‐arc setting. This finding represents and adds on to the N‐S geodynamic convergence model between the AYD and the northern border of the Congo Craton.

Characteristics of Cu-Au-Bearing Quartz Veins at Danyore Valley Area, Kohistan Terrane, Northern Pakistan: Evidence from Geological, Geochemical, and Geochronological Studies

“…Cathodoluminescence images (CL; Figure 5) were utilized for point selection for the trace element studies (SDT II) to assess the internal structure and outer appearance (morphology) of the specimens. Generally, zircon grains from studied gabbro and diorite samples are brassy yellow to light yellow and mostly anhedral to subhedral crystals that were fractured amidst the ascending of metamorphism or magma and alteration activity, which causes the zircon breakdown (Ayonta Kenne et al, 2021). CL reveals zircon crystals with sizes ranging from large (>210 μm) to short (<60 μm), displaying prismatic and pyramid shapes.…”

“…In sample SD-6 (Diorite), the presence of fluid or mineral inclusions, alteration, and metamorphism suggested a lack of clear zoning in studied zircon crystals. (Ayonta Kenne et al, 2021). The crystal structures of zircons vary from euhedral to subhedral, ranging in size between 90 to 190 μm, and axial ratios of 1:1 and 2:2 (Figure 5c).…”

Mineralogy, Petrography and Geochemistry of the Ina Syenite (Lint&#233;, Central Cameroon) as a Source of Industrial Feldspars

“…Depending on the age, the granitoids are syntectonic (630 -620 Ma), late tectonic (600 -580 Ma) and posttectonic (550 Ma) [31] [43]. The plutonic rocks of Linté batholith mainly consist of syenite and monzonite and were emplaced between 590 and 599 Ma, suggesting their classification as syn-to post-collisional granitoids related to the Pan-African Orogeny [44]. Most granitoids are syntectonic belonging to the potassic shoshonitic calc-alkaline series [2]; they are metallic to slightly peraluminous [38] [45] [46] and orthogneissified with a calc-alkaline tendency, high potassic to aluminous [32] [36] [38] [40].…”