Geology of the El Teniente orebody with emphasis on wall-rock alteration

Camus, Francisco

doi:10.2113/gsecongeo.70.8.1341

Cited by 61 publications

(57 citation statements)

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“…4d) that are common in the Upper Miocene Stern and Skewes, 1995;Kay et al, 2005), the host plutons of El Teniente deposit (solid squares, circles and triangles; Skewes et al, 2002;Stern et al, 2010), the regionally defined Young Plutonic Complex (open triangles; Kay et al, 2005), and younger Pliocene lavas from the valley of the Cachapoal River (circles; Stern and Skewes, 1995). The figure illustrated the progressive temporal increase in 87 Sr/ 86 Sr and decrease in Є Nd from the Early Miocene to the Pliocene for igneous rocks at the latitude of El Teniente as pointed out previously by Stern and Skewes (1995), Kay et al (2005) and Stern et al (2010 Lindgren and Bastin (1922), Howell and Molloy (1960), Camus (1975) and Cuadra (1986) for these same reasons.…”

Section: Petrochemical Classification Of the Dikessupporting

confidence: 77%

“…Pale-green clinopyroxene occurs in some of the more mafic of these dikes (Ttc1; 4d) and commonly contain orthopyroxene. Their textural and mineralogic characteristics suggest that they are genetically related to the more mafic mantle-derived olivine+hornblende lamprophyres in the Quebrada los Sapos, and that for this reason they are better classified as hornblende lamprophyres, as they were originally by Lindgren and Bastin (1922), Howell and Molloy (1960), Camus (1975) and Cuadra (1986), rather than as hornblende andesites. Both the mafic and intermediate lamprophyre dikes have relatively high Sr=600 to 920 ppm (Table 3; except for the most silica-rich sample ET-12C for which Sr=340 ppm), low Y (12-17 ppm), and consequently high Sr/Y ratios (43-71), similar to adakitic andesites, but these rocks, which range from basaltic to dacitic in composition, are not adakites.…”

Section: Sample Petrochemistrymentioning

confidence: 98%

“…Kay et al (2005) referred to these dikes as Late Hornblende dikes, and Maksaev et al (2004) referred to them as hornblende andesites based on major element compositions. However, they either completely lack or contain only scarce plagioclase feldspar phenocrysts and had, for this reason, been identified in the past as lamprophyres (Lindgren and Bastin, 1922;Howell and Molloy, 1960;Camus, 1975;Cuadra, 1986). Here we describe mafic olivine+hornblende-bearing dikes outcropping in the Quebrada los Sapos west of El Teniente mine (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Diques lamprofidicos de olivino-hornblenda de la quebrada los Sapos, El Teniente, Chile central (34°S): implicancias para la evolucion temporal de la geoquimica del manto subarco Andino.

Stern¹,

Floody²,

Espiñeíra³

2011

Andgeo

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AbSTRACT. Mafic Mg-olivine (Fo88)+hornblende lamprophyre dikes, with Ni ~190 ppm and Cr ~390 ppm, cut late Miocene lavas in the Quebrada los Sapos a few kilometers west of the El Teniente Cu-Mo mine. These dikes have petrochemical affinities with other less primitive, Pliocene (2.9-3.9 Ma), olivine-free lamprophyres previously described from both within and in the vicinity of El Teniente. The mafic mantle-derived lamprophyre dikes from Quebrada los Sapos have La/Yb ratios of 10-13, higher than the ratios of 4-9 for older Late Miocene El Teniente Mafic Complex olivine basalts, suggesting a temporal decrease in the percent of partial mantle melting, consistent with the observed decrease in the volume of igneous rocks through time at this latitude, as well as the ultimate cessation of magmatism and >40 km eastward arc migration by the Late Pliocene. Less primitive olivine-free lamprophyres have higher La and lower Yb, resulting in higher La/Yb ratios of 15-44, due to crystal-liquid fractionation involving hornblende, but not plagioclase, the crystallization of which is suppressed by the high H 2 O contents of the lamprophyres. The lamprophyre dikes, as well as younger ( 1. Pb, and lower Є Nd for mantle-derived mafic magmas, and by implication their mantle source region. Significantly Sr, Nd and Pb isotopic compositions are independent of SiO 2 content for rocks in each age group, which precludes contamination by isotopically heterogeneous Paleozoic and Mesozoic continental crust during evolution of intermediate and silicic rocks from mantle-derived mafic magmas. The Oligocene to Pliocene isotopic evolution of the mantle source of the mafic magmas may be explained by an increase from 1% to 6% in the extent of mantle source region contamination by subducted components, including continental crust tectonically eroded off the continental margin. We attribute this to both decreasing subduction angle and increasing rates of subduction erosion associated with the southward migration of the locus of subduction of the Juan Fernández Ridge. The lamprophyres also imply increased hydration of the mantle below this portion of the arc by the Pliocene, which may have played an important role in producing oxidized volatile-rich magmas and mineralization at El Teniente. sapOs, el TenienTe, CenTral Chile (34°s)... RESumEn. Diques lamprofídicos de olivino-hornblenda de la quebrada los Sapos, El Teniente, Chile central (34°S): implicancias para la evolución temporal de la geoquímica del manto subarco Andino. Diques de lampró-fidos máficos, con fenocristales de olivino magnésicos (Fo88)+hornblendas y contenidos de Ni ~190 ppm y Cr 390 ppm, cortan lavas miocénicas superior en la quebrada los Sapos a escasos kilómetros al oeste del depósito de Cu-Mo El Teniente. Estos diques tienen afinidades petroquímicas con otros diques lamprofídicos del Plioceno (2,9-3,9Ma), menos primitivos y sin fenocristales de olivinos, los cuales han sido descritos tanto dentro como alrededor de El Teniente. Estos diques de lamprófidos máficos en la quebrada lo...

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Section: Petrochemical Classification Of the Dikessupporting

confidence: 77%

Section: Sample Petrochemistrymentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Diques lamprofidicos de olivino-hornblenda de la quebrada los Sapos, El Teniente, Chile central (34°S): implicancias para la evolucion temporal de la geoquimica del manto subarco Andino.

Stern¹,

Floody²,

Espiñeíra³

2011

Andgeo

View full text Add to dashboard Cite

show abstract

“…Stein et al, 1998;Selby and Creaser, 2001;Bingen, 2002 Bingen andStein, 2003;Ootes et al, 2007;Bingen et al, 2008;Lawley and Selby, 2012). This, combined with the fact that molybdenite is the third most abundant ore mineral at El Teniente (Camus, 1975) analysis revealed that the amount of molybdenite in all selected type 3-4b veins was either insufficient for dating or it was the result of overprinting by later vein generations. As a result, no samples from this paragenetic stage were dated in this study.…”

Section: Geochronologymentioning

confidence: 99%

“…The tectonic setting, regional geology and magmatic-hydrothermal evolution of El Teniente have been the focus of numerous studies over the last 90 years (Lindgren and Bastin, 1922;Howell and Malloy, 1960;Camus, 1975;Charrier et al, 2002;Skewes et al, 2002;Maksaev et al, 2004Maksaev et al, , 2009Cannell et al, 2005Cannell et al, , 2007Skewes and Stern, 2007;Klemm et al, 2007;Rabbia et al, 2009;Astudillo et al, 2010;Stern et al, 2010;Vry et al, 2010;Muñoz et al, 2012). Combined, these investigations have helped build an understanding of the magmatic and hydrothermal evolution of the deposit.…”

Section: Geological Settingmentioning

confidence: 99%