The geology and Mesozoic collisional history of the Cordillera Real, Ecuador

Aspden, J. A.; Litherland, M.

doi:10.1016/0040-1951(92)90426-7

Cited by 123 publications

(74 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Ecuador consists of several terranes, both with continental and oceanic affinity, which were accreted onto the Amazon craton from the Early Cretaceous to the Eocene (Feininger 1987;Mourier et al 1988;Aspden and Litherland 1992;van Thournout et al 1992;Litherland et al 1994;Jaillard and Soler 1996;Jaillard et al 1997;Reynaud et al 1999;Hughes and Pilatasig 2002;Mamberti et al 2003). From east to west the following domains are recognized ( Fig.…”

Section: Geological Setting Geodynamic Evolution and Magmatismmentioning

confidence: 99%

Cenozoic continental arc magmatism and associated mineralization in Ecuador

Chiaradia

Fontboté

Beate

2004

Mineralium Deposita

View full text Add to dashboard Cite

Most of the economic ore deposits of Ecuador are porphyry-Cu and epithermal style gold deposits associated with Tertiary continental arc magmatism. This study presents major and trace element geochemistry, as well as radiogenic isotope (Pb, Sr) signatures, of continental arc magmatic rocks of Ecuador of Eocene to Late Miocene ($50-9 Ma, ELM) and Late Miocene to Recent ($8-0 Ma, LMR) ages. The most primitive ELM and LMR rocks analyzed consistently display similar trace element and isotopic signatures suggesting a common origin, most likely an enriched MORB-type mantle. In contrast, major and trace element geochemistry, as well as radiogenic isotope systematics of the whole sets of ELM and LMR samples, indicate strikingly different evolutions between ELM and LMR rocks. The ELM rocks have consistently low Sr/Y, increasing Rb/Sr, and decreasing Eu/Gd with SiO 2 , suggesting an evolution through plagioclase-dominated fractional crystallization at shallow crustal levels (<20 km). The LMR rocks display features of adakite-type magmas (high Sr/Y, low Yb, low Rb/Sr) and increasing Eu/Gd and Gd/Lu ratios with SiO 2 . We explain the adakitetype geochemistry of LMR rocks, rather than by slab melting, by a model in which mantle-derived melts partially melt and assimilate residual garnet-bearing mafic lithologies at deeper levels than those of plagioclase stability (i.e., >20 km), and most likely at sub-crustal levels (>40-50 km). The change in geochemical signatures of Tertiary magmatic rocks of Ecuador from the ELM-to the LMR-type coincides chronologically with the transition from a transpressional to a compressional regime that occurred at $9 Ma and has been attributed by other investigations to the onset of subduction of the aseismic Carnegie ridge.The major districts of porphyry-Cu and epithermal deposits of Ecuador (which have a small size, <<200 Mt, when compared to their Central Andean counterparts) are spatially and temporally associated with ELM magmatic rocks. No significant porphyry-Cu and epithermal deposits (except the epithermal highsulfidation mineralization of Quimsacocha) appear to be associated with Late Miocene-Recent (LMR, $8-0 Ma) magmatic rocks. The apparent ''infertility'' of LMR magmas seems to be at odds with the association of major porphyry-Cu/epithermal deposits of the Central Andes with magmatic rocks having adakite-type geochemical signatures similar to LMR rocks. The paucity of porphyry-Cu/epithermal deposits associated with LMR rocks might be only apparent and bound to exposure level, or real and bound (among other possibilities) to the lack of development of shallow crustal magmatic chambers since $9 Ma as a result of a prolonged compressional regime in the Ecuadorian crust. More work is needed to understand the actual metallogenic potential of LMR rocks in Ecuador.

show abstract

Section: Geological Setting Geodynamic Evolution and Magmatismmentioning

confidence: 99%

Cenozoic continental arc magmatism and associated mineralization in Ecuador

Chiaradia

Fontboté

Beate

2004

Mineralium Deposita

View full text Add to dashboard Cite

show abstract

“…These terranes were accreted to the continental margin (Sub-Andean Zone and Amazon Basin, Fig. 1b) between the Late Jurassic and the Late Cretaceous (Feininger 1987;Megard 1989;Jaillard et al 1990Jaillard et al , 1997Aspden and Litherland 1992;Litherland et al 1994;Kerr et al 1997;Reynaud et al 1999;Hughes and Pilatasig 2002;Mamberti et al 2003;Kerr and Tarney 2005;Vallejo et al 2006). Geophysical (Feininger and Seguin 1983) and geochemical (e.g., Mamberti et al 2003) data indicate the existence of an oceanic plateau basement in the Coastal Plain and under the Western Cordillera of Ecuador upon which various Late Cretaceous and Tertiary arcs were built.…”

Section: Geological and Geotectonic Settingmentioning

confidence: 99%

“…In contrast, the basement underneath the Inter-Andean Depression remains elusive due to the thick Tertiary and Quaternary volcanoclastic cover (a zone of tectonic melange has been proposed by Spikings et al 2005). The basement of the Eastern Cordillera consists of metamorphic Paleozoic to Jurassic rocks that would belong to both continental (schists, gneisses, granites) and oceanic (metabasalts) accreted terranes (Aspden and Litherland 1992;Litherland et al 1994). Recently, however, Pratt et al (2005) have questioned the allochthonous nature of the Eastern Cordillera terranes.…”

Section: Geological and Geotectonic Settingmentioning

confidence: 99%

“…It is located in the Eastern Cordillera (Fig. 1b) upon the basement of the Loja continental terrane (Paleozoic gneisses and schists as well as Triassic granites) and of the Alao island arc terrane (Jurassic meta-basalts) (Aspden and Litherland 1992;Litherland et al 1994;Noble et al 1997). Chacana was constructed from at least three cycles of andesitic-to-rhyolitic volcanism.…”

Section: Ilalo and Chacana (Main Arc)mentioning

confidence: 99%

See 1 more Smart Citation

Adakite-like volcanism of Ecuador: lower crust magmatic evolution and recycling

Chiaradia

Müntener

Beate

et al. 2009

Contrib Mineral Petrol

138

View full text Add to dashboard Cite

In the Northern Andes of Ecuador, a broad Quaternary volcanic arc with significant across-arc geochemical changes sits upon continental crust consisting of accreted oceanic and continental terranes. Quaternary volcanic centers occur, from west to east, along the Western Cordillera (frontal arc), in the Inter-Andean Depression and along the Eastern Cordillera (main arc), and in the Sub-Andean Zone (back-arc). The adakite-like signatures of the frontal and main arc volcanoes have been interpreted either as the result of slab melting plus subsequent slab melt-mantle interactions or of lower crustal melting, fractional crystallization, and assimilation processes. In this paper, we present petrographic, geochemical, and isotopic (Sr, Nd, Pb) data on dominantly andesitic to dacitic volcanic rocks as well as crustal xenolith and cumulate samples from five volcanic centers (Pululagua, Pichincha, Ilalo, Chacana, Sumaco) forming a NW-SE transect at about 0°latitude and encompassing the frontal (Pululagua, Pichincha), main (Ilalo, Chacana), and back-arc (Sumaco) chains. All rocks display typical subduction-related geochemical signatures, such as Nb and Ta negative anomalies and LILE enrichment. They show a relative depletion of fluid-mobile elements and a general increase in incompatible elements from the front to the back-arc suggesting derivation from progressively lower degrees of partial melting of the mantle wedge induced by decreasing amounts of fluids released from the slab. We observe widespread petrographic evidence of interaction of primary melts with mafic xenoliths as well as with clinopyroxene-and/or amphibole-bearing cumulates and of magma mixing at all frontal and main arc volcanic centers. Within each volcanic center, rocks display correlations between evolution indices and radiogenic isotopes, although absolute variations of radiogenic isotopes are small and their values are overall rather primitive (e.g., e Nd = ?1.5 to ?6, 87 Sr/ 86 Sr = 0.7040-0.70435). Rare earth element patterns are characterized by variably fractionated light to heavy REE (La/Yb N = 5.7-34) and by the absence of Eu negative anomalies suggesting evolution of these rocks with limited plagioclase fractionation. We interpret the petrographic, geochemical, and isotopic data as indicating open-system evolution at all volcanic centers characterized by fractional crystallization and magma mixing processes at different lower-to mid-crustal levels as well as by assimilation of mafic lower crust and/or its partial melts. Thus, we propose that the adakite-like signatures of Ecuadorian rocks (e.g., high Sr/Y and La/Yb values) are primarily the result of lower-to mid-crustal processing of mantle-derived melts, rather than of slab melts and slab melt-mantle interactions. The isotopic signatures of the least evolved adakite-like rocks of the active and recent volcanoes are the same as those of Tertiary ''normal'' calc-alkaline magmatic rocks of Ecuador suggesting that the source of the magma did not change 123Contrib Mineral Petrol (2009) 1...

show abstract

“…A evolução Triássica câracteriza-se pela estreita relaçåo entre metamorfismo e magmatismo (Roldan, 1993, Vinasco, 2001), e regionalmente tem s¡do conelacionada com o evento tectonomagmáiico Moromoro no Equador, associado a um regime transpressivo-transtensivo, aparentemente contemporâneo às primeiras fases da separaçâo da Pangea (Aspden et al,, 1992 a, b, L¡therland et al, '1994, Vinasco et al, 2OO1). o cretáceo lnferior está caraclerizado por uma sedimentaÉo de caráer marinho (Toussaint, 1996), que no cretáceo Médio e superior é afetada por uma serie de eventos colisionais relacionados à acresçäo e inteEção com alguns dos domínios vulcanG-sedimentares Cretáceos de afinidade oceânica que constituem a Cordilheira Ocidental da Colômbia (Mccourt et al, 1984, Toussaint, 1996 (Toussaint, 1996, Villamil, j99g).…”

unclassified

Correlações entre fragmentos do embasamento pré-mesozóico da terminação setentrional dos Andes Colombianos, com base em dados isotópicos e geocronológicos

Molina¹

View full text Add to dashboard Cite

El Padre Sol marcó su sendero dorado sobre las altas cumbres, asi creó a las montañas, los templos del sol.Fertilizó las lagunas, madres de la tierra y origen de la gente. Trazó los rios, caminos de los primeros hombresTodo esto fue creado del mar, cuando el sol y la luna llegaron al cielo El sol es un hombre con máscara de oro.De ella salen Éyos, y esos rayos hacen que la vida nazca y que todo crezca.Mitología Kogi (Tribu da Serra Nevada de Santa Marta, Coraçäo do Mundo) A mis padres Silvia y Mario por su eterna complicidad y amistad.A Marcela por la fuerza y la inspiración.A los tres por el gran amor que merecen.Um homem sáb¡o d¡sse faz alguns anos que nossas "conquistas" são possíveis porque såo feitas sobre os "ombros de gigantes". Eu quero agradecer às pessoas e entidades que contribuíram no desenvolvimento deste trabalho de mestrado.A meu orientador Prof. Dr. Umberto Cordani por ter aberto as portas para in¡ciar estudos de pós-graduaçåo, pela constante e fundamental guia, e pelo apoio neste processo de (Mueller et al., 1994, Nance e Murphy, 1994, Tosdal, 1996, Kepp¡e et al., 1998, Dickin, 2000 Paleozóico (Dalziel, 1994, Sadowsky e Bettencourt, 1996, Tosdal, 1996 (MgO, SiO2, MnO, CaO) ao longo do rnetamorfismo (W¡nchester e FLoyd,1977, Beccaluva et al., 1983, Mclenann et al, 1993 Os outros barômetros (Hammarstrom e zen,1986, Hollister et al., 1987, Johnson e Rutherford, 1989, Schmidt, 1992 (Dahl, 1996(Dahl, , V¡llä, '1997 (Galvis et al , 1979). Diques e s¡lls máficos aparecem intrusivos nas diferentes unidades (Priem et al., 1982 Na nomenclatura e definição dos tenenos såo utilizadas as propostas de Restrepo e Toussaint (1988) na Colômbia, Litherland et al (1994) A un¡dade ma¡s antiga está const¡tuída por um embasamento metamórfico de alto grau (fácies anfibolito alto -fácies granulito), e idâde entre 1.'1 e 1-0 Ga (Kroonemberg, 1982, Priem et al., 1989, Toussaint, 1993, Restrepo-Pace, 1997.Em discordância sobre estas unidades mais antigas encontra-se uma serie de seqüências metamórficas e sedimentares do Paleozóico lnferior (Ward et al, 1973, Toussa¡nt, 1993. Uma e),.tensa atividade plutônica com 500 Ma e 440 Ma, sin a pos{ectônica, com afinidade de arco mâgmático, encontra-se estreitamente relacionada ao metamoffismo regional e à evolução destas seqùências Paleozóicas (Ward et al, 1973, Boinet et al., 1985, Toussaint, 1993, Restrepo-Pace, 1995, Schafer et al., 1998 (Tschanz et al., 1969, Mojica et al., 1984, Toussa¡nt, 1993. Ativiclade magmática estâria associada a este evento, e inclui a ativ¡dade plutônica e vulcânica da Sena de perijá e a serra Nevada de santa Marta (Tschanz et al., 1969, Rabe, 1977 O Mesozóico está caracterizado por um magmatismo de caráter plutônico e vulcánico, em parte de natureza cátc¡o-alcalina (Maze, 1984, Alvarez, 19g6, Aspden et al., 1987 Toussaint, 1999, Toussaint, 1996. conesponde a uma sene de comprexos metamórfìcos e gran¡tóides associados, formados em amb¡entes tectônicos ainda não totalmente comprêendidos (Toussaint, 1993 (Lockwood, 1966, Alvarez, 1...

show abstract

The geology and Mesozoic collisional history of the Cordillera Real, Ecuador

Cited by 123 publications

References 15 publications

Cenozoic continental arc magmatism and associated mineralization in Ecuador

Cenozoic continental arc magmatism and associated mineralization in Ecuador

Adakite-like volcanism of Ecuador: lower crust magmatic evolution and recycling

Correlações entre fragmentos do embasamento pré-mesozóico da terminação setentrional dos Andes Colombianos, com base em dados isotópicos e geocronológicos

Contact Info

Product

Resources

About