3D Geophysical and Geological Modeling of the South Orkney Microcontinent (Antarctica): Tectonic Implications for the Scotia Arc Development

Morales-Ocaña, Cecilia; Bohoyo, Fernando; Escutia, Carlota; Marín‐Lechado, Carlos; Rey‐Moral, Carmen; Druet, M.; Galindo-Zaldı́var, Jesús; Maestro, Adolfo

doi:10.1029/2022tc007602

Cited by 3 publications

(2 citation statements)

References 61 publications

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“…Regions where plate convergence and subduction with rollback interact, such as Mediterranean orogenic arcs (e.g., Van Hinsbergen et al., 2014; Wortel & Spakman, 2000), the Banda Arc in eastern Indonesia (Pownall et al., 2013; Spakman & Hall, 2010), or the Scotia Arc between South America and Antarctica (Barker, 2001; Morales‐Ocaña et al., 2023; van de Lagemaat et al., 2021), are conducive to the development of extensional detachment systems. The uplift of certain areas, attributed to crustal thickening resulting from thrust and fold development (Tricart et al., 1994), shear zones (Morales‐Ocaña et al., 2023), and/or slab tearing (Delph et al., 2017; Parera‐Portell et al., 2023), occurs concurrently with subsidence, including the formation of back‐arc basins (Balázs et al., 2022; Larter et al., 2003). These geodynamic phenomena occur in close proximity, facilitating the orogenic collapse of the upper crust from uplifted regions to subsided ones.…”

Section: Discussionmentioning

confidence: 99%

“…While the extensional system in the central Betic Cordillera migrates in the same direction of the Gibraltar Arc, in other settings this is not the case. In the Banda Arc, the extension's migration is perpendicular to the subduction's migration (Pownall et al., 2013), and in the Scotia Arc, it is parallel but in the opposite direction (Morales‐Ocaña et al., 2023). Furthermore, the model proposed here suggests that gravitational collapse can migrate, as seen during the Cenozoic in the Great Basin (Axen et al., 1993) or in the Tibetan Plateau, Himalaya (Guo et al., 2018), if the lithospheric processes generating them migrate in turn.…”

Section: Discussionmentioning

confidence: 99%

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Active Shortening Simultaneous to Normal Faulting Based on GNSS, Geophysical, and Geological Data: The Seismogenic Ventas de Zafarraya Fault (Betic Cordillera, Southern Spain)

Madarieta‐Txurruka,

González‐Castillo,

Peláez

et al. 2024

Tectonics

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The central Betic Cordillera, southern Spain, is affected by an uplift related to the NNW–SSE Eurasia‐Nubia convergence and shallow ENE–WSW orthogonal extension accommodated by the extensional system of the Granada Basin. The combination of geophysical, geodetic, and geological data reveals that the southwestern boundary of this extensional system is a seismically active compressional front extending from the W to the SW of the Granada Basin. The near‐field Global Navigation Satellite System data determine NNE–SSW shortening of up to 2 mm/yr of the compressional front in the Zafarraya Polje. In this setting, the normal Ventas de Zafarraya Fault developed as a result of the bending‐moment extension of the Sierra de Alhama antiform and was last reactivated during the 1884 Andalusian earthquake (Mw 6.5). The uplift in the central Betic Cordillera together with the subsidence in the Western Alborán Basin may facilitate a westward to southwestward gravitational collapse through the extensional detachment of the Granada Basin. The heterogeneous crust of the Betic Cordillera would generate the compressional front, which is divided into two sectors: thrusting to the west, and folding associated with buttressing to the south. Our results evidence that basal detachments, linking extensional fault activity with compressional fronts, may determine the activity of local surface structures and the geological hazard in densely populated regions.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Active Shortening Simultaneous to Normal Faulting Based on GNSS, Geophysical, and Geological Data: The Seismogenic Ventas de Zafarraya Fault (Betic Cordillera, Southern Spain)

Madarieta‐Txurruka,

González‐Castillo,

Peláez

et al. 2024

Tectonics

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Comparing geophysical inversion and petrophysical measurements for northern Victoria Land, Antarctica

Lowe,

Jordan,

Ebbing

et al. 2024

Geophysical Journal International

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Summary Bedrock geology from Antarctica remains largely unknown since it is hidden beneath thick ice sheets. Geophysical methods such as gravity and magnetic inverse modelling provide a framework to infer crustal rock properties indirectly in Antarctica. However, due to limited availability of rock samples, validation against direct geological information is challenging. We present a new rock property catalogue containing density and susceptibility measurements on 320 rock samples from northern Victoria Land. This catalogue is used to assess the reliability of local and regional scale inverse results, including a new local high resolution magnetic inversion in the Mesa Range region and a previously published regional scale joint inversion of gravity and magnetic data in northern Victoria Land and the Wilkes Subglacial Basin. We compare our density and susceptibility measurements to global and local measurements from the literature to access the correlation to rock types and geological units. Furthermore, the measured values are compared against inverted values. The close correspondence between inverted and measured rock properties allows us to predict locations of rock types where currently such information is missing. The utility of measured susceptibility and density relationships for interpreting inversion output provides a strong incentive to incorporate local rock samples into geophysical studies of subglacial geology across Antarctica.

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Cretaceous–Paleogene tectonic reconstructions of the South Scotia Ridge and implications for the initiation of subduction in the Scotia Sea

Riley

Burton‐Johnson

Hogan

et al. 2023

JGS

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The Cenozoic development of the Scotia Sea and opening of Drake Passage led to the dispersal of crustal blocks of the North and South Scotia ridges that today have a strong influence on the pathway of the Antarctic circumpolar current. The pre-translation positions of the crustal fragments of the Scotia ridges are uncertain, with correlations to both the Antarctic and South American plates. We present direct geochronology ( 40 Ar/ 39 Ar) from Bruce and Jane banks of the South Scotia Ridge that yield Late Cretaceous – Paleogene ages indicating a pre-translation magmatic history. Basaltic magmatism from Bruce Bank is calc-alkaline, akin to Cenozoic magmatism of the South Orkney microcontinent and the South Shetlands Islands, and in agreement with pre-translation tectonic models that place the crustal blocks of the South Scotia Ridge adjacent to the northern Antarctic Peninsula arc. The intra-oceanic arc magmatism at Jane Bank is Late Cretaceous in age (97.2 ± 1.1 Ma), and is not consistent with models suggesting a Miocene origin as part of the ancestral South Sandwich arc. The development of westward-directed subduction adjacent to Jane Bank is predicted in some tectonic models as a consequence of Late Cretaceous plate dynamics that developed prior to the Oligocene – Miocene ancestral arc. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6639909

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3D Geophysical and Geological Modeling of the South Orkney Microcontinent (Antarctica): Tectonic Implications for the Scotia Arc Development

Abstract: The origin of the Scotia Arc lies in the early stages of the fragmentation of the supercontinent Gondwana during the late Mesozoic (Dalziel et al.

Cited by 3 publications

References 61 publications

Active Shortening Simultaneous to Normal Faulting Based on GNSS, Geophysical, and Geological Data: The Seismogenic Ventas de Zafarraya Fault (Betic Cordillera, Southern Spain)

Active Shortening Simultaneous to Normal Faulting Based on GNSS, Geophysical, and Geological Data: The Seismogenic Ventas de Zafarraya Fault (Betic Cordillera, Southern Spain)

Comparing geophysical inversion and petrophysical measurements for northern Victoria Land, Antarctica

Cretaceous–Paleogene tectonic reconstructions of the South Scotia Ridge and implications for the initiation of subduction in the Scotia Sea

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