Geochemistry of the Taitao ophiolite and near-trench intrusions from the Chile margin triple junction

Kaeding, Margaret E.; Forsythe, Randy; Nelson, Eric P.

doi:10.1016/0895-9811(90)90001-h

Cited by 52 publications

(43 citation statements)

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“…The Seno Hoppner granitoids have granitic composition (sensu stricto) and low Sr/Y ratio (1.3-1.5). These results are consistent with those reported by Kaeding et al (1990).…”

Section: Geochemical Compositionsupporting

confidence: 94%

“…Nevertheless, it remains controversial even in its whole rock composition of major and trace elements. Kaeding et al (1990), the first to report whole rock compositions of the Taitao (Kaeding et al, 1990). However, the Eu anomaly of the Cabo Raper pluton is much lower than that of the Seno Hoppner pluton, which is consistent with higher content in Ca and Sr of the former.…”

Section: Geochemical Compositionmentioning

confidence: 74%

“…They inferred that the granitoids were formed through assimilation of basaltic magma with forearc sediment or metamorphic basement because the Sr and Nd isotope compositions of the granitoids (0.704353-0.704974 in 87 Sr/ 86 Sr and +1.3 to +4.7 in ε Nd ) are shown between those of the basalt in the Taitao ophiolite (0.702709, +9.7) and sediment/metamorphic basement (0.715475, -8.2). These isotopic compositions are explainable by 5-15% mixing of crustal components for basaltic end-members of this region (Kaeding et al, 1990).…”

Section: Geochemical Compositionmentioning

confidence: 78%

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Petrogenesis of the ridge subduction-related granitoids from the Taitao Peninsula, Chile Triple Junction Area

et al. 2013

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“…The Seno Hoppner granitoids have granitic composition (sensu stricto) and low Sr/Y ratio (1.3-1.5). These results are consistent with those reported by Kaeding et al (1990).…”

Section: Geochemical Compositionsupporting

confidence: 94%

Section: Geochemical Compositionmentioning

confidence: 74%

Section: Geochemical Compositionmentioning

confidence: 78%

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Petrogenesis of the ridge subduction-related granitoids from the Taitao Peninsula, Chile Triple Junction Area

et al. 2013

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“…To the southeast of this baythmetric ridge, a large ophiolite complex has been mapped on the Taitao Peninsula (Forsythe et al, 1986). This uplifted complex, and some associated "near-trench plutons" (Kaeding et al, 1990), are dated by K/Ar and micropaleontologic findings as late Miocene to Pliocene in age (Mpodozis et al, 1985;Forsythe et al, 1985). The age and location of the onshore magmatic rocks has tied their formation and uplift to the late Cenozoic arrival and subduction of the Chile Rise spreading center along the Peru-Chile Trench.…”

Section: Introductionmentioning

confidence: 99%

Data Report: 40Ar/39Ar and Additional Paleontologic Age Constraints, Site 862, Taitao Ridge

Forsythe¹,

Drake²,

Olsson³

1995

Proceedings of the Ocean Drilling Program, 141 Scientific Results

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This paper presents additional chronological data for samples obtained during Leg 141 of the Ocean Drilling Program. The samples were obtained from Hole 862C, located on the Taitao Ridge, an anomalous bathymetric promontory that juts out from the Pacific continental margin of South America near the Chile Margin Triple Junction (latitude ~46-47°S).Four samples were selected for 40 Ar/ 39 Ar isotopic dating. Two of these samples were hornblende rhyolite, and the other two were phyric basalt. Hornblende separates from the rhyolitic samples provide ages of 1.54 ± 0.08 Ma and 2.2 ± 0.4 Ma. Low K contents in the basaltic samples and their slight alteration inhibited more precise age determinations.One sample, Sample 141-862C-6R-1, 36-44 cm (Piece 6), from the Taitao Ridge, is an indurated fragment of sandstone with carbonate and volcanic clasts. Foraminifer tests isolated from this fragment have yielded age diagnostic planktonic species indicative of a very late Paleocene age. The benthic and planktonic species suggest middle shelf depths.

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“…Several authors have pointed to a close spatial and temporal relation between the processes of 6 Ma ophiolite emplacement (Anma et al, 2006) and the evolution of the active Chile Ridge system that separate the Nazca (to the north) and Antarctic (to the south) oceanic plates (e.g., Cande and Leslie, 1986;Forsythe and Nelson, 1985;Nelson et al, 1993;Keading et al, 1990;Bourgois et al, 1996;Lagabrielle et al, 1994Lagabrielle et al, , 2000Veloso et al, 2005). According to global plate reconstructions and numerical models (e.g., NUVEL1-A) the Nazca plate is presently subducting at a rate of about 8.5 cm/yr in a N80°E direction whereas the Antarctic plate subducts at a rate of ca.…”

Section: Introductionmentioning

confidence: 99%

Emplazamiento de ofiolitas y los efectos de la subduccion de la dorsal activa de Chile: Regimenes heterogeneos de paleostress registrados en la Oflolita Taitao (Sur de Chile).

Veloso¹,

Anma²,

Yamaji³

2009

Andgeo

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ABSTRACT. The repeated north and southward migration of the Chile Triple junction, offshore the Península de Taitao, is expected to have imposed contrasting stress fi elds in the forearc for the last 6 Ma because of changes in convergence direction and rate of subducting plates. NNW-SSE to E-W and minor NE-SW striking brittle faults developed in the plutonic units of the Mio-Pliocene Taitao Ophiolite, whereas NNE-SSW and minor NW-SE trending faults developed in its eastern border (Bahía Barrientos fault-zone). These brittle faults are studied to elucidate the style of ophiolite emplacement and the tectonic effects resulting from the alternated migration of the Chile Triple junction in the area. Analyses of heterogeneous fault-slip data on both areas suggest that faults were activated by different stress fi elds. Two different compressional stress fi elds were identifi ed in the plutonic units (A and B), whereas three different stress fi elds, ranging from compressional to strike-slip, were identifi ed in the Bahía Barrientos fault-zone (C, D and E). Calculated directions of σ 1 axes for A, C, D and E solutions are mostly E-W trending, roughly similar to the convergence direction of subducting plates, whereas that for B solution is counterclockwise rotated ca. 60° with respect to the previous E-W trend. Brittle structures related to solution B were attributed to an early deformation of the ophiolite, most probably developed shortly after its emplacement (ca. 6 Ma). These structures were further counterclockwise rotated, while new structures (related to solution A) developed in the plutonic units in order to absorb the continuous deformation. In the eastern margin of the ophiolite, the stress fi eld divided into compressional and strike-slip components. During periods of relatively strong compression (fast subduction of the Nazca plate), the fault-zone experienced well defi ned compressional and strike-slip movements (solutions C and D). In contrast, during periods of relatively weak compression (slow subduction of the Antarctic plate), the fault-zone experienced a complex mixture of thrust and strike-slip movements (solution E). Thus, the wide range of calculated stress ratios for all solutions could be attributed to the alternated change in convergent velocity of the subducting plates beneath the Taitao area. RESUMEN.Emplazamiento de ofi olitas y los efectos de la subducción de la dorsal activa de Chile: Regímenes heterogéneos de paleostress registrados en la Ofi olita Taitao (Sur de Chile). Es esperable que la repetida migración norte-sur del Punto Triple de Chile cercana a la costa de la Península de Taitao haya impuesto campos de esfuerzos distintos en el antearco por los últimos 6 Ma debido a cambios en la dirección de convergencia y tasa de subducción. Fallas con rumbos NNO-SSE y E-O y otras menores con rumbos NE-SO se desarrollaron en las unidades plutónicas de la Ofi olita Miocena-Pliocena de Taitao, mientras que fallas con rumbos NNE-SSO y otras menores con rumbos NO-SE se desarrollaron en el borde Est...

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Geochemistry of the Taitao ophiolite and near-trench intrusions from the Chile margin triple junction

Cited by 52 publications

References 50 publications

Petrogenesis of the ridge subduction-related granitoids from the Taitao Peninsula, Chile Triple Junction Area

Petrogenesis of the ridge subduction-related granitoids from the Taitao Peninsula, Chile Triple Junction Area

Data Report: 40Ar/39Ar and Additional Paleontologic Age Constraints, Site 862, Taitao Ridge

Emplazamiento de ofiolitas y los efectos de la subduccion de la dorsal activa de Chile: Regimenes heterogeneos de paleostress registrados en la Oflolita Taitao (Sur de Chile).

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