The Significance of Bioturbated Inclined Heterolithic Stratification in the Southern Part of the Miocene Solimoes Formation, Rio Acre, Amazonia Brazil

Gingras, Murray K.; Räsänen, Matti; Ranzi, Alceu

doi:10.1669/0883-1351(2002)017<0591:tsobih>2.0.co;2

Cited by 87 publications

(76 citation statements)

References 18 publications

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“…Nevertheless, as their modern counterparts, Miocene brackishwater deposits do not necessary exhibit size reduction in burrows produced by such crustacean as Thalassinoides, Ophiomorpha and Psilonichnus (e.g. Rosseti, 2000; Gingras et al, 2002;Carmona et al, 2009). Crustacean dwelling structures at RDB (Ophiomorpha isp.)…”

Section: Paleontologymentioning

confidence: 99%

Paleoenvironmental reconstruction of the coastal Monte Léon and Santa Cruz formations (Early Miocene) at Rincón del Buque, Southern Patagonia: A revisited locality

Raigemborn

Matheos

Krapovickas

et al. 2015

Journal of South American Earth Sciences

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a b s t r a c tSedimentological, ichnological and paleontological analyses of the Early Miocene uppermost Monte Le on Formation and the lower part of the Santa Cruz Formation were carried out in Rinc on del Buque (RDB), a fossiliferous locality north of Río Coyle in Santa Cruz Province, Patagonia, Argentina. This locality is of special importance because it contains the basal contact between the Monte L eon (MLF) and the Santa Cruz (SCF) formations and because it preserves a rich fossil assemblage of marine invertebrates and marine trace fossils, and terrestrial vertebrates and plants, which has not been extensively studied. Ã 90 m-thick section of the MLF and the SCF that crops out at RDB was selected for this study. Eleven facies associations (FA) are described, which are, from base to top: subtidaleintertidal deposits with Crassotrea orbignyi and bioturbation of the Skolithos-Cruziana ichnofacies (FA1); tidal creek deposits with terrestrial fossil mammals and Ophiomorpha isp. burrows (FA2); tidal flat deposits with Glossifungites ichnofacies (FA3); deposits of tidal channels (FA4) and tidal sand flats (FA5) both with and impoverish Skolithos ichnofacies associated; marsh deposits (FA6); tidal point bar deposits recording a depauperate mixture of both the Skolithos and Cruziana ichnofacies (FA7); fluvial channel deposits (FA8); fluvial point bar deposits (FA9); floodplain deposits (FA10); and pyroclastic and volcaniclastic deposits of the floodplain where terrestrial fossil mammal remains occur (FA11).The transition of the MLFeSCF at RDB reflects a changing depositional environment from the outer part of an estuary (FA1) through the central (FA2e6) to inner part of a tide-dominated estuary (FA7). Finally a fluvial system occurs with single channels of relatively low energy and low sinuosity enclosed by a broad, low-energy floodplain dominated by partially edaphized ash-fall, sheet-flood, and overbank deposits (FA8e11). Pyroclastic and volcaniclastic materials throughout the succession must have been deposited as ash-fall distal facies in a fluvial setting and also were carried by fluvial streams and redeposited in both estuarine and fluvial settings. These materials preserve most of the analyzed terrestrial fossil mammals that characterize the Santacrucian age of the RDB's succession. Episodic sedimentation under volcanic influence, high sedimentation rates and a relatively warm and seasonal climate are inferred for the MLF and SCF section.Lateral continuity of the marker horizons at RDB serve for correlation with other coastal localities such as the lower part of the coastal SCF south of Río Coyle (~17.6e17.4 Ma) belonging to the Estancia La Costa Member of the SCF.

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Section: Paleontologymentioning

confidence: 99%

Paleoenvironmental reconstruction of the coastal Monte Léon and Santa Cruz formations (Early Miocene) at Rincón del Buque, Southern Patagonia: A revisited locality

Raigemborn

Matheos

Krapovickas

et al. 2015

Journal of South American Earth Sciences

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“…A global eustasy sea-level fall can be ruled out as the Late Other parts of the Amazonian foreland sedimentation were widely controlled by deltaic and estuarine sedimentation during the Late Miocene (Fig. 5.10) including the wedge-top depozone (Hermoza et al 2005b), the foredeep depozone (Hermoza 2004;Roddaz 2004;Roddaz et al 2004;Hovikoski et al 2005;Burgos 2006), the forebulge depozone (Roddaz et al , 2006Rebata-Hernani et al 2006a, 2006b and the backbulge depozone (Gingras et al 2002;Roddaz et al 2005aRoddaz et al , 2006. The Late Miocene Amazonian foreland basin system may therefore be interpreted as a fi lled foreland basin system (Catuneanu 2004).…”

Section: Eocene: Erosional Unloadingmentioning

confidence: 99%

Cenozoic Sedimentary Evolution of the Amazonian Foreland Basin System

Roddaz

Hermoza

Mora

et al. 2009

Amazonia: Landscape and Species Evolution

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In this chapter we present a synthesis of the Cenozoic evolution of the Amazonian foreland basin system, based on a review of the estimated ages, lithology and sedimentary structures, palaeontological content, and inferred depositional environments of sedimentary units in the basin. In addition, we have calculated maximum sedimentation rates for the Cenozoic formations of the northern Peruvian foreland basin and integrated these with existing data on sedimentation rates, subsidence analysis, migration of depocentre and depositional environments. Based on this information we propose a model for the Cenozoic evolution of the Amazonian foreland. The sedimentary architecture of this foreland basin indicates that Cenozoic evolution was marked by several periods, which were roughly synchronous and of similar effect, along the entire Amazonian foreland basin system. Tectonic loading of the Andes of Colombia, Ecuador, Peru and northern Bolivia, and development of the Amazonian foreland, was initiated during Late Cretaceous-Paleocene times and followed by an unloading stage during the Early-Middle Eocene period. The Middle-Late Eocene marine transgression and the increase in sedimentation rates, associated with westward migration of the depocentre, were all indicative of a renewed phase of tectonic loading of the Peruvian Western Cordillera and the Ecuadorian and Colombian Eastern Cordillera. Subsequent Oligo-Miocene increase in sedimentation rates and further migration of the depocentres towards the present-day sub-Andean zone, are all indicative for a thrust-induced uplift and loading of the Eastern Cordilleras of Peru, Bolivia and Colombia. This Oligo-Miocene loading stage maintained high subsidence rates that favoured the sedimentation of aggradational fl oodplain and coastal plain and tidally infl uenced deposits. Nevertheless, the processes that controlled the Early-Middle Miocene marine ingressions remain to be determined. Late Miocene ongoing thrust tectonic loading of the Eastern Cordillera, initial structuring of the sub-Andean zone and the onset of the main phase of Andean surface uplift induced fl exural subsidence in the foredeep depozones of the entire Amazonian foreland basin. This process also drove the Late Miocene marine transgressions that characterized the fi lled stage of the Ecuadorian, Peruvian and Bolivian Amazonian foreland basin system. Valley incisions and full relief development in the hinterland during the Late Miocene-Pliocene provided increased sediment supply and overfi lled the Amazonian foreland basin system. Finally, the fl at-slab subduction of the Nazca ridge induced Pliocene (~4 Ma) uplift of the Fitzcarrald Arch and subdivided the Amazonian foreland basin into the northern and southern Amazonian foreland basins.

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“…Dalrymple 2006, i.e. estuary is transgressive) channel complexes that are interbedded with a variety of alluvial strata (Gingras et al 2002b;Hovikoski et al 2005Hovikoski et al , 2007aHovikoski et al , 2008Rebata et al 2006). Generally, tidally infl uenced IHS is believed to form as a result of migration of turbidity maxima, which is caused by estuarine circulation and intermingling of tidal and fl uvial currents (e.g., Dalrymple & Choi 2007).…”

Section: Early-middle Miocene ('Pebas Phase')mentioning

confidence: 99%

Marine influence in Amazonia: Evidence from the Geological Record

Hovikoski

Wesselingh

Räsänen

et al. 2009

Amazonia: Landscape and Species Evolution

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Marine infl uence in Amazonia during the Miocene is a controversial issue, one about which nearly opposite theories (continental vs marine) have been proposed. Increasing multidisciplinary palaeoenvironmental data sets from various Miocene stratigraphic levels and parts of Amazonia have revealed depositional complexities triggered by repeated, high-frequency base-level changes and a very low depositional gradient. As a result, Early-Middle Miocene strata (Pebas phase) are organized into recurring 3-10 m-thick transgressive-regressive bay-margin successions. An array of evidence indicates some sort of marine infl uence in these deposits. This evidence includes mangrove pollen, foraminifers, rare brackish-water mollusc species, barnacles, common brackish-water trace fossil assemblages and tidal sediments. The ongoing debate now focuses on the degree of saltwater infl uence in the Pebas phase strata. The Late Miocene (Acre phase) stratigraphic record comprises mainly channelized deposits, and fossil faunas are dominated by terrestrial and freshwater vertebrates. The evidence for marginal marine infl uence in these strata is mainly confi ned to inclined heterolithic stratifi cation (IHS)-bearing channels and includes tidal sediments, restricted brackish-water ichnofossil assemblages, and locally teeth of euryhaline sharks and mangrove pollen (Nauta and Madre de Dios Formations). In particular, the tidal signature in these deposits is well developed, pointing to local development of deltaic/estuarine settings. There are also suggestions of marine infl uence on other stratigraphic intervals throughout Amazonia, particularly in Pliocene and Quaternary strata. The allegedly marine conditions have been proposed based on purported global sea-level highstands, the low altitude of the Amazon region and supposed coastal geomorphological features such as deltas. We conclude that these suggestions are misconceptions and that geological data to support such marine settings during the Late Neogene are lacking.

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The Significance of Bioturbated Inclined Heterolithic Stratification in the Southern Part of the Miocene Solimoes Formation, Rio Acre, Amazonia Brazil

Cited by 87 publications

References 18 publications

Paleoenvironmental reconstruction of the coastal Monte Léon and Santa Cruz formations (Early Miocene) at Rincón del Buque, Southern Patagonia: A revisited locality

Paleoenvironmental reconstruction of the coastal Monte Léon and Santa Cruz formations (Early Miocene) at Rincón del Buque, Southern Patagonia: A revisited locality

Cenozoic Sedimentary Evolution of the Amazonian Foreland Basin System

Marine influence in Amazonia: Evidence from the Geological Record

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