The early Paleozoic evolution of the Argentine Precordillera as a Laurentian rifted, drifted, and collided terrane: A geodynamic model

Astini, Ricardo A.; Benedetto, Juan L.; Vaccari, N. Emilio

doi:10.1130/0016-7606(1995)107<0253:tepeot>2.3.co;2

Cited by 377 publications

(327 citation statements)

References 0 publications

Supporting

Mentioning

303

Contrasting

Unclassified

Order By: Relevance

“…The previously described Early Ordovician, high-level low-grade metamorphism within the internal part of the Famatina thrust-fold belt is consistent with the ages of associated metamorphism and deformation elsewhere and, Figure 12. Map of the southern central Andes showing contour for the Precordillera terrane (including the Precordillera thrust-fold belt and the outcrops of its Grenville basement and cover rocks, modified from Astini et al [1995] and Sato et al [2000], and the Famatinian belt as depicted by Pankhurst et al [2000]). PT, Precordillera terrane; FB, Famatinian belt.…”

Section: Age Of Deformation Within the Famatinian Belt And Its Bearinmentioning

confidence: 99%

“…Astini et al, 1995]. This microplate has been interpreted as a driftedrifted crustal block from the Ouachita embayment of southeastern Laurentia [Thomas and Astini, 1996;Dalziel, 1997;Astini, 1998a] that accreted to western Gondwana by MidLate Ordovician time [e.g., Astini et al, 1995;Thomas and Astini, 2003]. On the basis of preliminary analyses of detrital zircons [Finney et al, 2003a], the Laurentian origin of the Argentine Precordillera has recently been questioned, which in turn, greatly modifies the plate tectonic reconstructions (for a thorough dis-cussion, see Aceñolaza et al [2002]; Astini and Rapalini [2003]).…”

Section: Introductionmentioning

confidence: 99%

“…In the eastern foothills of the Andes of Argentina, on the western South American margin, a wellstudied example is the Precordillera terrane [cf. Astini et al, 1995]. This microplate has been interpreted as a driftedrifted crustal block from the Ouachita embayment of southeastern Laurentia [Thomas and Astini, 1996;Dalziel, 1997;Astini, 1998a] that accreted to western Gondwana by MidLate Ordovician time [e.g., Astini et al, 1995;Thomas and Astini, 2003].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ordovician back arc foreland and Ocloyic thrust belt development on the western Gondwana margin as a response to Precordillera terrane accretion

2004

View full text Add to dashboard Cite

The Famatina belt, southern central Andes, records a circa 470 m.y. shortening episode (Ocloyic orogeny) affecting the peri‐Gondwanan back arc basin in response to the accretion of the Precordillera terrane. Collision created distinct features across and along the margin, some of which persisted into the present Andean structure. From east to west, the Ocloyic deformation is recorded across the telescoped region of Famatina, represented by (1) an east vergent fold‐thrust belt (EVFTB) involving a major angular unconformity between Early and Middle Ordovician rocks, (2) a highly deformed volcano‐sedimentary belt, and (3) an east vergent ductile shear zone affecting Famatinian granites. Axis attitudes of Ordovician refolded anticlines in the EVFTB show west‐east tectonic transport, in agreement with kinematics of Ocloyic high‐strain belts, indicating shortening orthogonal to the present Pacific margin. Eastward displacement of the Ordovician volcanic arc at ∼27°S latitude together with a documented sinistral slip zone across the proto‐Andean margin suggests tectonic indentation.

show abstract

Section: Age Of Deformation Within the Famatinian Belt And Its Bearinmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ordovician back arc foreland and Ocloyic thrust belt development on the western Gondwana margin as a response to Precordillera terrane accretion

2004

View full text Add to dashboard Cite

show abstract

“…This new record shows that Amsassia emerged from the eastern margin of Laurentia, since the Argentine Precordillera rifted from this continent by the late Cambrian (Astini et al, 1995;Benedetto, 2004). Subsequent records occur in the Middle Ordovician of the Sino-Korean and Tarim block , and later the expansion continued in Siberia and Kazakhstan.…”

Section: Paleogeographic Distribution Of Amsassia and Its Role In Thementioning

confidence: 99%

“…The La Silla Formation (Keller et al, 1994) is considered to be an ancient tropical Bahamian-type platform (Cañas, 1999;Keller, 1999;Pratt et al, 2012) that accumulated on a uniformly subsiding passive margin within the exotic Precordillera terrane (Astini et al, 1995;Gomez and Astini, 2015). Paleogeographically, by this time, the Precordillera terrane was drifting within the southern Iapetus Ocean (Astini et al, 1995;Benedetto, 2004;Keller, 2012). From a stratigraphic viewpoint, it represents the transition from the late Cambrian largely fossil-barren cyclic peritidal dolomites (Zonda and La Flecha formations) into fossiliferous open-shelf pure limestones of the Ordovician San Juan Formation ( Fig.…”

Section: Geological Settingmentioning

confidence: 99%

A lowermost Ordovician tabulate-like coralomorph from the Precordillera of western Argentina: a main component of a reef-framework consortium

Carrera¹,

Astini²,

Gómez³

2016

J. Paleontol.

View full text Add to dashboard Cite

Abstract.-Although putative corals of uncertain affinities occur in the early Cambrian, the earliest definite tabulate corals have not been described prior to the Early Ordovician in North America. This paper reports a new finding of a tabulate-like coralomorph forming part of biostratigraphically well-constrained reef mounds in the latest Cambrian-Early Ordovician La Silla Formation in the Argentine Precordillera. The oldest record of the coralomorph genus Amsassia is reported and a new species, A. argentina, is erected. The discovery of this genus in the lowermost Ordovician modifies the previously proposed paleogeographic distribution and patterns of origination and migration routes of this coral-like organism. Amsassia argentina n. sp. constitutes a main framework builder together with a complex microbial consortium. This oldest occurrence of Amsassia as a reef builder represents a new record of a skeletal organism in the gap of metazoan reef constructors after the demise of archaeocyaths in the late early Cambrian.

show abstract

Multiple migmatite events and cooling from granulite facies metamorphism within the Famatina arc margin of northwest Argentina

et al. 2014

View full text Add to dashboard Cite

The Famatina margin records an orogenic cycle of convergence, metamorphism, magmatism, and extension related to the accretion of the allochthonous Precordillera terrane. New structural, petrologic, and geochronologic data from the Loma de Las Chacras region demonstrate two distinct episodes of lower crustal migmatization. The first event preserves a counterclockwise pressure-temperature path in kyanite-K-feldspar pelitic migmatites that resulted in lower crustal migmatization via muscovite dehydration melting at ∼12 kbar and 868 • C at 461 ± 1.7 Ma. The shape of the pressure temperature path and timing of metamorphism are similar to those of regional midcrustal granulites and suggest pervasive Ordovician migmatization throughout the Famatina margin. One-dimensional thermal modeling coupled with regional isotopic data suggests Ordovician melts remained at temperatures above their solidus for 20-30 Ma following peak granulite facies metamorphism, throughout a time period marked by regional oblique convergence. The onset of synconvergent extension occurred only after regional migmatites cooled beneath their solidus and was synchronous with the cessation of Precordillera terrane accretion at ∼436 Ma. The second migmatite event was regionally localized and occurred at ∼700 • C and 12 kbar between 411 and 407 Ma via vapor saturated melting of muscovite. Migmatization was synchronous with extension, exhumation, and strike-slip deformation that likely resulted from a change in the plate boundary configuration related to the convergence and collision of the Chilenia terrane.

show abstract

The early Paleozoic evolution of the Argentine Precordillera as a Laurentian rifted, drifted, and collided terrane: A geodynamic model

Cited by 377 publications

References 0 publications

Ordovician back arc foreland and Ocloyic thrust belt development on the western Gondwana margin as a response to Precordillera terrane accretion

Ordovician back arc foreland and Ocloyic thrust belt development on the western Gondwana margin as a response to Precordillera terrane accretion

A lowermost Ordovician tabulate-like coralomorph from the Precordillera of western Argentina: a main component of a reef-framework consortium

Multiple migmatite events and cooling from granulite facies metamorphism within the Famatina arc margin of northwest Argentina

Contact Info

Product

Resources

About