P-T conditions of earliest Late Cretaceous metamorphism in the Western Sonobari Complex, northwestern Mexico: tectonic implications

Vega-Granillo, Ricardo; Sarmiento-Villagrana, Alicia; Salgado-Souto, Sergio Adrián; Araux-Sánchez, Elizabeth

doi:10.1080/00206814.2016.1227942

Cited by 6 publications

(5 citation statements)

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“…A regional metamorphism and related foli a tion overprint all units described above excluding the Cenomanian diorite. Thermobarometry yields average pressure (P ) and temperature (T ) of 8.0 ± 0.9 kb (kilobar) and 699 ± 42 °C, respectively, indicating a medium P/T amphibo lite facies metamorphism (Vega-Granillo et al, 2017). Migmatization is common in orthogneisses and metasedimentary rocks mainly as stromatic bands, patches of leucosome, and veins, all indicating low melt volume.…”

Section: Western Sonobari Complexmentioning

confidence: 99%

“…Migmatization is common in orthogneisses and metasedimentary rocks mainly as stromatic bands, patches of leucosome, and veins, all indicating low melt volume. Metamorphism was dated at 91 Ma on recrystallized zircon rims (Sarmiento-Villagrana et al, 2016;Vega-Granillo et al, 2017).…”

Section: Western Sonobari Complexmentioning

confidence: 99%

“…Following emplacement of the mafic dikes, a collision event occurred, which caused deformation and orogenic metamorphism. Considering the age of the involved rocks, this event could be related to the collision of the Alisitos oceanic arc against the continental border (Sarmiento-Villagrana et al, 2016;Vega-Granillo et al, 2017). The final collisional event has been dated in Baja California at between 111 and 103 Ma (Johnson et al, 1999;Schmidt et al, 2014).…”

Section: Neovolcanic Axismentioning

confidence: 99%

“…100 Ma. Thermobarometry of the metamorphic rocks indicates that the region underwent burial to a depth of ~30 km (Vega-Granillo et al, 2017). During the latest stages of this event, the Río Fuerte Formation was thrust over the Topaco Formation causing heterogeneous mylonitic deformation and greenschist facies metamorphism in both units and in the Cubampo Granite (Vega-Granillo et al, 2011.…”

Section: Neovolcanic Axismentioning

confidence: 99%

“…In the WSC, thermal readjustment caused a temperature peak and migmatization at ca. 90 Ma (Sarmiento-Villagrana et al, 2016;Vega-Granillo et al, 2017), ca.10 Ma after cessation of the deformation event. That thermal peak was enhanced by Cenomanian post-tectonic gabbro plutons, and diorite, hornblendite, and pyroxenite dikes.…”

Section: Neovolcanic Axismentioning

confidence: 99%

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Geochemical and isotopic study of Mesozoic magmatism in the Sonobari Complex, western Mexico: Implications for the tectonic evolution of southwestern North America

et al. 2017

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The Sonobari Complex in northwestern Mexico preserves evidence of the consolidation of Pangaea and the Cordilleran orogenic cycle. Six Meso zoic magmatic pulses extending from the Early Triassic to the Paleocene are recognized in this complex. The volumetrically predominant rocks are calcalkaline metaluminous and peraluminous granitoids. Mafic rocks are mainly tholeiitic gabbros. All studied rocks show high concentrations of large ion lithophile elements (LILE) and negative Nb, Ta, and Ti anomalies. Initial Nd and Sr isotopic ratios in granitoids (εNd (i) = -5.7 to -0.5; 87 Sr/ 86 Sr (i) = 0.70630-0.71302) point to evolved continental sources, while radiogenic Pb isotopes ( 206 Pb/ 204 Pb (i) = 16.292-19.17; 207 Pb/ 204 Pb (i) = 15.503-15.666; 208 Pb/ 204 Pb (i) = 35.257-38.984) indicate a heterogeneous basement. Initial Nd and Sr isotope ratios in mafic rocks (εNd (i) = -1.9 to +5.0; 87 Sr/ 86 Sr (i) = 0.70384-0.70626) point to mantle sources with crustal assimilation, which is also supported by the radiogenic Pb values ( 206 Pb/ 204 Pb (i) = 18.412-19.081; 207 Pb/ 204 Pb (i) = 15.595-15.672; 208 Pb/ 204 Pb (i) = 38.147-38.988).Geochemical and isotopic signatures suggest that magmatic rocks in the complex orig inated from fractional crystallization with assimilation of a heterogeneous basement isotopically similar to the Grenville orogen of Mexico. Whole rock compositions are compatible with volcanicarc followed by backarc tectonic settings, where subduction and extensional processes occurred. Therefore, the main granitic pulses in the Sonobari Complex originated af ter the late Paleozoic GondwanaLaurentia collision, by subduction of oce anic plates or microplates along the western border of Pangea. Also, two extensionrelated magmatic pulses occurred after the Late Jurassic and in the Cenomanian, separated by a collisional orogenic event that is recorded by regional metamorphism. The continental arc setting of the Sonobari Complex differs from the oceanic arc context of the GuerreroAlisitos super terrane, indicating that there is no genetic relation between these blocks as previously proposed; rather, a relationship with the eastern Peninsular Ranges batholith is proposed.

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Section: Western Sonobari Complexmentioning

confidence: 99%

Section: Western Sonobari Complexmentioning

confidence: 99%