Sedimentologic development of a Late Oligocene–Miocene forearc embayment, Valdivia Basin Complex, southern Chile

Roux, J.P. Le; Elgueta, Sara

doi:10.1016/s0037-0738(99)00096-2

Cited by 29 publications

(19 citation statements)

References 24 publications

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“…This coincides with the beginning of marine transgression at around 15 Ma and the greatest depositional water depths recorded between 12-11 Ma in the Coquimbo Basin (Le , as well as a change from estuarine peat swamp conditions to deep marine embayments in the Valdivia and Osorno Basins (Fig. 1) during the Middle Miocene (Le Roux and Elgueta, 2000;Elgueta et al, 2005). Tectonic subsidence accompanied by marine transgression during the Middle Miocene thus affected around 1,000 km of coastline between 30°S-40°S.…”

Section: Depositional Environment and Tectonic Eventssupporting

confidence: 54%

Evidence for an Early-Middle Miocene age of the Navidad Formation (central Chile): Paleontological, paleoclimatic and tectonic implications

Gutiérrez

Hinojosa

Roux

et al. 2013

andgeo

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ABSTRACT. The age of the Navidad Formation in central Chile has always been controversial, mainly due to the conflicting age ranges indicated by its macro-and microfossils. Macrofossils are generally interpreted as having been reworked from older, Early to Middle Miocene strata, whereas a Late Miocene-Pliocene age has been accepted on the basis of planktonic foraminifer index species. The results of this study, however, indicate that the macrofossils occur in situ, which necessitates a complete revision of the geochronological data. It is concluded that the evidence for an Early to Middle Miocene age is overwhelming, and that the planktonic foraminifer index species must have appeared in the SE Pacific earlier than elsewhere. These include Globoturborotalia apertura, Globorotalia puncticulata (Deshayes), Globorotalia spheriomizea (Walters), Neogloboquadrina pachyderma (Ehrenberg), and Neogloboquadrina acostaensis (Blow). An Early to Middle Miocene age for the Navidad Formation correlates well with a reinterpretation of its depositional environment as a continental shelf instead of a deepwater continental slope, global and regional paleoclimatic events, and the tectonic development of the Andes Range. RESUMEN. Evidencias de una edad miocena temprana-media de la Formación Navidad: Implicancias paleontológicas, paleoclimáticas y tectónicas. La edad de la Formación Navidad en Chile central siempre ha sido controversial, debido a los distintos rangos de edad indicados por los macro-y microfósiles. En general, se considera que los macrofósiles han sido retrabajados de estratos del Mioceno Temprano a Medio, y se aceptó una edad miocena tardía para esta unidad sobre la base de especies indicadoras de foraminíferos planctónicos. Sin embargo, los resultados de este estudio indican que los macrofósiles ocurren in situ, lo cual hace necesario una revisión completa de los datos geocronológicos. Se concluye que la evidencia por una edad miocena temprana a media es contundente, y que los foraminíferos planctónicos que indicarían una edad miocena tardía aparecieron más temprano en el SE del océano Pacífico que en otras partes. Estos foraminíferos incluyen Globoturborotalia apertura, Globorotalia puncticulata (Deshayes), Globorotalia spheriomizea (Walters), Neogloboquadrina pachyderma (Ehrenberg), y Neogloboquadrina acostaensis (Blow). Una edad miocena temprana a mediana correlaciona bien con la reinterpretación del ambiente deposicional como una plataforma continental en vez de un talud continental con agua profunda, eventos paleoclimáticos reconocidos a escala global y regional, y el desarrollo tectónico de los Andes. Medio, Tectonismo andino, Diagonal Árido. Palabras clave: Especies indicadoras de foraminíferos, Óptimo Climático del Mioceno

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Section: Depositional Environment and Tectonic Eventssupporting

confidence: 54%

Evidence for an Early-Middle Miocene age of the Navidad Formation (central Chile): Paleontological, paleoclimatic and tectonic implications

Gutiérrez

Hinojosa

Roux

et al. 2013

andgeo

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“…Without any confirmed lower Miocene strata along the western margin of central and southern Chile, there is no reliable means of distinguishing the supposedly reworked component from the in situ benthic fauna of mollusks, foraminifers, and ostracodes. Further investigation could fill this void, inasmuch as Le Roux and Elgueta (2000) reported an Oligocene to Miocene sequence in the Valdivia Basin. It is likely the Navidad fauna will also be present in sections purported to be younger than those of the Navidad Formation, such as Lo Abarca (Covacevich and Frassinetti, 1990), or containing an apparently mixed fauna of Miocene and Pliocene elements, such as Chepu (Watters and Fleming, 1972).…”

Section: Discussionmentioning

confidence: 99%

Paleontologic Evidence for Sedimentary Displacement in Neogene Forearc Basins of Central Chile

Finger

Nielsen

DeVries

et al. 2007

PALAIOS

110

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A consensus on the biostratigraphic age and depositional environment of the Navidad, Ranquil, and Lacui formations exposed along the tectonic margin of central Chile has been elusive due to conflicting evidence. This study resolves this dilemma and gains further insight regarding the history of the Chilean coast. Problematic interpretations stem primarily from the remarkable similarity between the molluscan fauna of these units with those well documented for the late Oligocene to early Miocene of Peru. Planktic foraminifers, however, indicate that the Chilean sections accumulated in the late Miocene to early Pliocene interval following a regional hiatus that extends into the Eocene. The prevalence of mixed-depth bathyal assemblages of benthic foraminifers and ostracodes, the majority of which include lower-bathyal (Ͼ2000 m) indicators, reveals that downslope displacement was a primary mode of deposition in the basins. Although the molluscan assemblages are dominated by shallow marine taxa, most include species that range into or are restricted to deeper waters. Sedimentary features connote rapid subsidence and deep-water deposition of gravity flows. Although older Tertiary and Cretaceous planktic foraminifers in several assemblages indicate reworking of older units, lack of data on pre-Tortonian faunas of this region precludes recognition of other age-discordant components that could constitute a significant portion of the recovered fauna. The findings of this study revise the prevailing conception of the region's geologic history that considered these units to be early to middle Miocene shelf deposits and indicate that infilling and uplift have characterized the nearshore basins since the late Pliocene.

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“…1). The Coastal Range is composed by metamorphic rocks, partially overlaid by Tertiary marine sediments, with intermediate slope angles, ranging from 300 to 1000 m in elevation (Servicio Nacional de Geología y Minería, 1982; Le Roux and Elgueta, 2000). The Central Depression is dominated by lahars and pyroclastic fluxes as well as till and outwash deposits, creating smooth slopes or flat areas at a general elevation of 100-300 m (Servicio Nacional de Geología y Minería, 1982).…”

Section: Study Areamentioning

confidence: 99%

Assessment of ecosystem services as an opportunity for the conservation and management of native forests in Chile

Lara

Little

Urrutia

et al. 2009

Forest Ecology and Management

171

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Sedimentologic development of a Late Oligocene–Miocene forearc embayment, Valdivia Basin Complex, southern Chile

Cited by 29 publications

References 24 publications

Evidence for an Early-Middle Miocene age of the Navidad Formation (central Chile): Paleontological, paleoclimatic and tectonic implications

Evidence for an Early-Middle Miocene age of the Navidad Formation (central Chile): Paleontological, paleoclimatic and tectonic implications

Paleontologic Evidence for Sedimentary Displacement in Neogene Forearc Basins of Central Chile

Assessment of ecosystem services as an opportunity for the conservation and management of native forests in Chile

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