Detrital-zircon geochronology and provenance of the El Oro Metamorphic Complex, Ecuador: Geodynamic implications for the evolution of the western Gondwana margin

Suhr, Nils; Rojas‐Agramonte, Yamirka; Chew, David; Pinto, André Jorge; Villagómez-Díaz, Diego; Toulkeridis, Theofilos; Mertz‐Kraus, Regina

doi:10.1016/j.jsames.2018.12.010

Cited by 15 publications

(22 citation statements)

References 39 publications

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“…1; Jaillard et al, 1999;Valarezo et al, 2019), and are intruded by the Marcabeli Pluton (U-Pb zircon ages 227-238 Ma; Aspden et al, 1995;Cochrane et al, 2014b;Paul et al, 2018) and host pre-Devonian acritarchs and spores (Zamora and Pothe de Baldis, 1988). U-Pb concordia dates of the youngest detrital zircons within a sandstone of the El Tigre Unit (sample EO4) constrain its maximum depositional age to 512 ± 21 Ma (Suhr et al, 2019). These constraints suggest a Cambrian -Silurian age for the El Tigre unit.…”

Section: Geological Framework and Previous Workmentioning

confidence: 89%

See 1 more Smart Citation

Constraints on the ages of the crystalline basement and Palaeozoic cover exposed in the Cordillera real, Ecuador: 40Ar/39Ar analyses and detrital zircon U/Pb geochronology

et al. 2021

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Section: Geological Framework and Previous Workmentioning

confidence: 89%

“…However, a paucity of studies of the pre-Triassic units (e.g. see Chew et al, 2008;Suhr et al, 2019) hinders geological models of the Pacific margin along southwestern Pangaea, which are currently heavily founded on the evolution of the Argentinian and Peruvian Andes (e.g. Cawood, 2005;Chew et al, 2007;Mišković et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Constraints on the ages of the crystalline basement and Palaeozoic cover exposed in the Cordillera real, Ecuador: 40Ar/39Ar analyses and detrital zircon U/Pb geochronology

et al. 2021

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“…550-510 Ma, suggesting an early Cambrian MDA. Alternatively, this zircon population is possibly related to igneous sources in the Pampean orogeny of Argentina (Casquet et al, 2018;Suhr et al, 2019).…”

Section: Correlation With Other Peri-gondwanan Blocksmentioning

confidence: 99%

Depositional age and provenance of high-grade paragneisses from the Mérida Andes, Venezuela: Implications for the Ediacaran–Cambrian tectonic setting of northwestern Gondwana

Tazzo-Rangel

Weber

Frei

et al. 2021

Lithos

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“…Serpentinites and other ultramafic rocks outcrop in the Amotape block and the Cordillera Real domains (Figure 2a). In the first one, they occur as W‐E‐oriented slivers tectonically associated with units of El Oro Metamorphic Complex; the Devonian Palenque mélange, the Triassic Piedras unit, and the Early Cretaceous Raspas Complex, respectively (Aspden et al., 1995; Gabriele, 2002; Litherland et al., 1994; Suhr et al., 2019). Ultramafic units in Palenque mainly comprise serpentinite bodies associated with minor gabbros and gabbroic pegmatites.…”

Section: Geological Setting and Sample Descriptionmentioning

confidence: 99%

Exhumed Serpentinites and Their Tectonic Significance in Non‐Collisional Orogens

Donoso‐Tapia,

Flores,

Martin

et al. 2024

Geochem Geophys Geosyst

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Exhumed serpentinites are fragments of ancient oceanic lithosphere or mantle wedge that record deep fluid‐rock interactions and metasomatic processes. While common in suture zones after closure of ocean basins, in non‐collisional orogens their origin and tectonic significance are not fully understood. We study serpentinite samples from five river basins in a segment of the non‐collisional Andean orogen in Ecuador (Cordillera Real). All samples are fully serpentinized with antigorite as the main polymorph, while spinel is the only relic phase. Watershed delineation analysis and in‐situ B isotope data suggest four serpentinite sources, linked to mantle wedge (δ11B = ∼−10.6 to −0.03‰) and obducted ophiolite (δ11B = −2.51 to +5.73‰) bodies, likely associated with Triassic, Jurassic‐Early Cretaceous, and potentially Late Cretaceous‐Paleocene high‐pressure (HP)–low‐temperature metamorphic sequences. Whole‐rock trace element data and in‐situ B isotopes favor serpentinization by a crust‐derived metamorphic fluid. Thermodynamic modeling in two samples suggests serpentinization at ∼550–500°C and pressures from 2.5 to 2.2 GPa and 1.0–0.6 GPa for two localities. Both samples record a subsequent overprint at ∼1.5–0.5 GPa and 680–660°C. In the Andes, regional phases of slab rollback have been reported since the mid‐Paleozoic to Late Cretaceous. This tectonic scenario favors the extrusion of HP rocks into the forearc and the opening of back‐arc basins. Subsequent compressional phases trigger short‐lived subduction in the back‐arc that culminates with ophiolite obduction and associated metamorphic rock exhumation. Thus, we propose that serpentinites in non‐collisional orogens are sourced from extruded slivers of mantle wedge in the forearc or obducted ophiolite sequences associated with regional back‐arc basins.

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Detrital-zircon geochronology and provenance of the El Oro Metamorphic Complex, Ecuador: Geodynamic implications for the evolution of the western Gondwana margin

Cited by 15 publications

References 39 publications

Constraints on the ages of the crystalline basement and Palaeozoic cover exposed in the Cordillera real, Ecuador: 40Ar/39Ar analyses and detrital zircon U/Pb geochronology

Constraints on the ages of the crystalline basement and Palaeozoic cover exposed in the Cordillera real, Ecuador: 40Ar/39Ar analyses and detrital zircon U/Pb geochronology

Depositional age and provenance of high-grade paragneisses from the Mérida Andes, Venezuela: Implications for the Ediacaran–Cambrian tectonic setting of northwestern Gondwana

Exhumed Serpentinites and Their Tectonic Significance in Non‐Collisional Orogens

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