Ordovician klippen structures of the Sierra de Umango: New insights on Tectonic evolution of the Western Sierras Pampeanas, Argentina

Meira, Vinícius Tieppo; Neto, Mário da Costa Campos; González, Pablo Diego; Basei, Miguel Ângelo Stipp; Varela, Ricardo

doi:10.1016/j.jsames.2012.02.002

Cited by 8 publications

(7 citation statements)

References 52 publications

(84 reference statements)

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“…Although the contact between the Zaino and Taco Complexes was not directly observed in this study, this model predicts a low angle thrust fault that is younger than the Silurian -Late Devonian deformation in the Zaino Complex. Additionally, this model predicts right-lateral faulting within the Sierra de Umango which is, at first order, supported by Meira et al (2012)…”

Section: Discussionsupporting

confidence: 52%

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Metamorphic Evolution of the Sierra De Maz: Implications for the Timing of Terrane Accretion on the Western Margin of Gondwana

Tholt¹,

Webber²,

Houlihan³

et al. 2017

Geological Society of America Abstracts With Programs

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The Mesoproterozoic MARA terrane of South America has been interpreted to collide and subduct beneath the Gondwana margin of South America in the Cambrian. To test the proposed tectonic model, I combine metamorphic petrology and geochronology along with quantitative thermobarometry to constrain metamorphic events and peak conditions within the Sierra de Maz of the MARA terrane and the adjacent Sierra de Ramaditas. Foliations within the Sierra de Maz are steeply east dipping, with a major sinistral reverse shear zone separating the two major units (Zaino and Maz Complexes) of the northern range. Garnet Lu-Hf records a single metamorphic event in the Zaino Complex at ~425 Ma. Combined garnet Lu-Hf and monazite U-Pb reveal a polymetamorphic history in the Maz Complex with two distinct metamorphic events at ~1.2 Ga and ~425 Ma. Both Complexes were deformed by sinstral transpression between 435 and 415 Ma. Preserved across these Complexes is a Silurian-Devonian amphibolite to granulite inverted metamorphic field gradient that is compatible with observed and modeled gradients from other transpressive orogens. The Ramaditas complex records lower-pressure granulite facies metamorphism at ~460 Ma, was deformed at ~426 Ma, and is correlated with the Famatina arc rather than its previously proposed affiliation to units in the Sierra de Maz. Units of the Sierra de Maz do not share metamorphic histories with nearby ranges within the proposed extent of the MARA terrane. Age dissimilarities require that portions of the MARA terrane were tectonically juxtaposed likely as a result of transpressive translation along the Gondwana margin.

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Section: Discussionsupporting

confidence: 52%

“…Figure 3: General geologic map of the Western Sierras Pampeanas and the Sierras de Maz, Espinal, Umango. The Sierra de Ramaditas is denoted by the map unit Fg (compiled and adapted after Meira et al, (2012) and references therein)…”

Section: Geology Of the Sierra De Mazmentioning

confidence: 99%

Metamorphic Evolution of the Sierra De Maz: Implications for the Timing of Terrane Accretion on the Western Margin of Gondwana

Tholt¹,

Webber²,

Houlihan³

et al. 2017

Geological Society of America Abstracts With Programs

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“…2). Instead, the Taco Complex may be regionally correlative with units in the Central Complex of the Sierra de Pie de Palo and/or Sierra de Umango because they have similar protoliths, peak metamorphic conditions, and metamorphic ages (e.g., Mulcahy et al, 2011;Varela et al, 2011;Meira et al, 2012;Ramacciotti et al, 2019a) (Figs. 11-12).…”

Section: Research Papermentioning

confidence: 99%

“…Basement terranes within the Western Sierras Pampeanas of northwest Argentina, located between the allochthonous Precordillera terrane to the west and the Cambrian-Ordovician continental Famatina arc to the east (Fig. 1), record a prolonged history of magmatism (e.g., Vujovich and Kay, 1998;Rapela et al, 2010Rapela et al, , 2018Varela et al, 2011;Ramos, 2018;Ramacciotti et al, 2019a), metamorphism (e.g., Casquet et al, 2001;Otamendi et al, 2008;Mulcahy et al, 2014), and deforma tion (e.g., Ramos et al, 1998;Mulcahy et al, 2007Mulcahy et al, , 2011Meira et al, 2012;Garber et al, 2014). Rapela et al (2010) distinguished two different domains within the Western Sierras Pampeanas (Fig.…”

Section: ■ Introductionmentioning

confidence: 99%

Metamorphism of the Sierra de Maz and implications for the tectonic evolution of the MARA terrane

et al. 2021

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The Mesoproterozoic MARA terrane of western South America is a composite igneous-metamorphic complex that is important for Paleozoic paleogeographic reconstructions and the relative positions of Laurentia and Gondwana. The magmatic and detrital records of the MARA terrane are consistent with a Laurentian origin; however, the metamorphic and deformation records lack sufficient detail to constrain the correlation of units within the MARA terrane and the timing and mechanisms of accretion to the Gondwana margin. Combined regional mapping, metamorphic petrology, and garnet and monazite geochronology from the Sierra de Maz of northwest Argentina sug- gest that the region preserves four distinct litho-tectonic units of varying age and metamorphic conditions that are separated by middle- to lower-crustal ductile shear zones. The Zaino and Maz Complexes preserve Barrovian metamorphism and ages that are distinct from other units within the region. The Zaino and Maz Complexes both record metamorphism ca. 430–410 Ma and show no evidence of the regional Famatinian orogeny (ca. 490–455 Ma). In addition, the Maz Complex records an earlier granulite facies event at ca. 1.2 Ga. The Taco and Ramaditas Complexes, in contrast, experienced medium- and low-pressure upper amphibolite to granulite facies metamorphism, respectively, between ca. 470–460 Ma and were later deformed at ca. 440–420 Ma. The Maz shear zone that bounds the Zaino and Maz Complexes records sinistral oblique to sinistral deformation between ca. 430–410 Ma. The data suggest that at least some units in the MARA terrane were accreted by translation, and the Gondwana margin of northwest Argentina transitioned from a dominantly convergent margin to a highly oblique margin in the Silurian.

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“…The origin and accretion of the Cuyania Terrane, which comprises the Western Sierras Pampeans (sensu Caminos, 1979) including the Sierra de Pie de Palo, during the Ordovician is still controversially discussed in the literature (e.g. Aceñolanza and Toselli, 1988;Finney et al 2003;Meira et al 2012;Mulcahy et al 2007;Ramos, 1988;Ramos et al 1998;Ramos, 2004;Thomas and Astini, 2003;van Staal et al 2011). On one hand, most authors agree that the exotic Cuyania, or Precordillera Terrane represents an allochthonous continental block derived from Laurentia and accreted to the southwestern proto-Andean margin of Gondwana during the Famatinian orogenic cycle in Middle Ordovician (e.g.…”

Section: Introductionmentioning

confidence: 99%

Multi-Method Chronometric Constraints on the Thermal, Structural and Morphotectonic Evolution of the Eastern and Western Sierras Pampeanas with Special Emphasis on K-Ar Dating of Fault Gouges

Bense¹

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Chapter 2 gives a methodological introduction to the thermochronological and chronological tools used. The principles of (U-Th)/He dating on zircon and apatite, apatite fission-track analyses and K-Ar illite fine-fraction dating are illustrated. An approach to forward and inverse modeling of thermochronological data is also elucidated. Chapter 3 presents a study of the southern Sierra de Comechingones. It depicts thermochronological data from the Yacanto area as well as K-Ar illite fine-fraction ages from fault gouges in the Merlo area. Findings from both methods are interpreted and discussed in relation to established cooling and uplift scenarios. This chapter was written in collaboration with Stefan Löbens (see Löbens 2012). Chapter 4 represents a study from the southern Sierra de San Luis. It presents thermochronological and fault-gouge analysis data from an elevation profile in the Nogolí area. Results are discussed regionally and, along with findings from the Sierra de Comechingones (Chapter 2), summarized in a morphotectonic model for the easternmost Pampean ranges. Additionally, thermochronological implications for the development of paleolandsurfaces are discussed. This chapter was written in collaboration with Stefan Löbens (see Löbens 2012). Chapter 5 is focused on the thermal history of the Sierra de Pie de Palo, which represents the westernmost branch of the Sierras Pampeanas. Based on AFT and (U-Th)/He data, the thermochronological development of the Sierra de Pie de Palo is illustrated and discussed in a regional context. This chapter was written in collaboration with Stefan Löbens (see Löbens 2012). Chapter 6 is dedicated to the analyses of gouge-bearing brittle fault zones in the Eastern Sierras Pampeanas. The data presented are derived from several methodological approaches, e.g. clay mineralogy, illite polytype quantification and K-Ar illite fine-fraction dating, as well as structural observations of gouge-bearing fault systems. In addition to data presented in Chapters 2 and 3, new data are presented from almost all ranges of the Eastern Sierras Pampeanas. Detailed discussion of results is focused on both regional and methodological aspects. The latter include a thorough review of existing K-Ar fault-gouge analysis concepts as well as a discussion of possibilities for crossevaluation of illite ages with results from other methods, e.g. thermochronology, geochronology and illite mineralogy. Chapter 7 presents new data from key positions in the Sierras Pampeanas, which allow us to extend the regional interpretations and thermal evolution models, discussed in Chapters 3 to 5, to the entire Pampean region. Results reveal significant differences in the Late Paleozoic to Neogene postaccretional cooling history between the northern, central and southern Pampeanas ranges. Spatially and timely differences in thermal history are illustrated and discussed in relation to main geodynamic and tectonic events as well as to established geological hypotheses. The results are condensed into a cooling and exhumat...

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Ordovician klippen structures of the Sierra de Umango: New insights on Tectonic evolution of the Western Sierras Pampeanas, Argentina

Cited by 8 publications

References 52 publications

Metamorphic Evolution of the Sierra De Maz: Implications for the Timing of Terrane Accretion on the Western Margin of Gondwana

Metamorphic Evolution of the Sierra De Maz: Implications for the Timing of Terrane Accretion on the Western Margin of Gondwana

Metamorphism of the Sierra de Maz and implications for the tectonic evolution of the MARA terrane

Multi-Method Chronometric Constraints on the Thermal, Structural and Morphotectonic Evolution of the Eastern and Western Sierras Pampeanas with Special Emphasis on K-Ar Dating of Fault Gouges

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