Ridge collision tectonics in terrane development

Nelson, Eric P.; Forsythe, Randall D.; Arit, I.

doi:10.1016/0895-9811(94)90013-2

Cited by 53 publications

(33 citation statements)

References 27 publications

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“…Quaternary deformation in the southern SVZ is localized in the intra-arc zone along the arc-parallel, strike-slip Liquine-Ofqui fault zone (LOFZ), an approximately 1,100 km long, dextral strike-slip system that accommodates part of the margin-parallel component of oblique subduction (Nelson et al, 1994;Cembrano et al, 1996;Lavenu and Cembrano, 1999;Rosenau et al, 2006). Several authors showed that the Quaternary southern volcanic zone is strongly controlled by the LOFZ south of 38 • (e.g., Hervé, 1994;Lopez-Escobar et al, 1995;Lavenu and Cembrano, 1999;Rosenau, 2004).…”

Section: Subduction Zonesmentioning

confidence: 99%

Volcanism in Reverse and Strike-Slip Fault Settings

Tibaldi

Pasquarè

Tormey³

2009

New Frontiers in Integrated Solid Earth Sciences

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Traditionally volcanism is thought to require an extensional state of stress in the crust. This review examines recent relevant data demonstrating that volcanism occurs also in compressional tectonic settings associated with reverse and strike-slip faulting. Data describing the tectonic settings, structural analysis, analogue modelling, petrology, and geochemistry, are integrated to provide a comprehensive presentation of this topic. An increasing amount of field data describes stratovolcanoes in areas of coeval reverse faulting, and shield volcanoes, stratovolcanoes, and monogenic edifices along strike-slip faults, whereas calderas are mostly associated with pull-apart structures in transcurrent regimes. Physically-scaled analogue experiments simulate the propagation of magma in these settings, and taken together with data from subvolcanic magma bodies, they provide insight into the magma paths followed from the crust to the surface. In several transcurrent tectonic plate boundary regions, volcanoes are aligned along both the strikeslip faults and along fractures normal to the local least principal stress (σ 3 ). At subduction zones, intraarc tectonics is frequently characterised by contraction or transpression. In intra-plate tectonic settings, volcanism can develop in conjunction with reverse faults or strike slip faults. In most of these cases, magma appears to reach the surface along fractures striking parallel to the local σ 1 . In some cases, there is a direct geometric control by the substrate strikeslip or reverse fault: magma is transported beneath A. Tibaldi ( ) Department of Geological Sciences and Geotechnologies, University of Milan-Bicocca, Italy e-mail: alessandro.tibaldi@unimib.it the volcano to the surface along the main faults, irrespective of the orientation of σ 3 . The petrology and geochemistry of lavas erupted in compressive stress regimes indicate longer crustal residence times, and higher degrees of lower crustal and upper crustal melts contributing to the evolving magmas when compared to lavas from extensional stress regimes. Small volumes of magma tend to rise to shallow crustal levels, and magma mixing is common in the compressional regimes. In detailed studies from the Andes and Anatolia, with geographic and temporal coverage with which to compare compressional, transcurrent and extensional episodes in the same location, there do not appear to be changes to the mantle or crustal source materials that constitute the magmas. Rather, as the stress regime becomes more compressional, the magma transport pathways become more diffuse, and the crustal residence time and crustal interaction increases.

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Section: Subduction Zonesmentioning

confidence: 99%

Volcanism in Reverse and Strike-Slip Fault Settings

Tibaldi

Pasquarè

Tormey³

2009

New Frontiers in Integrated Solid Earth Sciences

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“…This dextral strike-slip discontinuity is mainly a result of oblique plate convergence (Hervé, 1994) and collision of the Chile Rise at its southern end (Nelson et al, 1994). The LOFZ decouples the south-central Chilean forearc, which is suggested to behave as a northward gliding sliver (so-called 'Chiloé block', Fig.1) by several authors (Cembrano et al, 2002;Rosenau et al, 2006).…”

Section: Regional Tectonic and Geologic Settingmentioning

confidence: 99%

Forearc uplift rates deduced from sediment cores of two coastal lakes in south-central Chile

et al. 2010

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The present paper introduces a new approach for deriving information about local forearc tectonics and related uplift rates based on the study of lake sediments. We investigated two coastal lakes at the south-central Chile margin, lakes Lanalhue and Lleu Lleu, located south of the Arauco Peninsula (38°S). Both lakes developed within the valleys of ancient rivers that once drained to the Pacific Ocean, being subsequently dammed by rising sills in the late Pleistocene/early Holocene. Seismic profiling and sedimentological analyses of cores from both lakes revealed similar successions consisting of marine to brackish sediments covered by lacustrine deposits. Radiocarbon dating indicates that the marine-lacustrine transition occurred at 8 ka and 8.15 ka, respectively. The correlation of this transition with global sea-level curves allowed the calculation of local uplift rates for the Holocene. Uplift rates for the lake basins amount to 0.42 ± 0.71 and 0.49 ± 0.44 mm/a, respectively, which are consistent with rates determined from a late Pleistocene marine terrace in the area. However, conspicuously higher, though likely transient, vertical movements at 8.83 ± 2.7 mm/a and 11.36 ±1.77 mm/a, respectively, were calculated for the sills that block both lakes nowadays. These barriers are interpreted to be the surface expression of a blind reverse fault associated to the Morguilla fault system, a seismically-active structure that controls uplift and folding along the adjacent Arauco Peninsula.

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“…Such division of the stress fi eld (e.g., Fitch, 1972) has been proposed for other parts of the Andean orogen, like for example the Chiloé block north of the Península de Taitao (e.g., Forsythe and Nelson, 1985;Nelson et al, 1994) and, in particular, for the dextral transpression documented in the arc at the latitude of the Península de Taitao associated in time and space to the subduction of the Chile Ridge system Thomson, 2002).…”

Section: Fig 4 Histograms and Best-fi Tting Normal Distribution Formentioning

confidence: 99%

Ophiolite Emplacement and the Effects of the Subduction of the Active Chile Ridge System: Heterogeneous Paleostress Regimes Recorded in the Taitao Ophiolite (Southern Chile)

Veloso

Anma

Yamaji

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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Ridge collision tectonics in terrane development

Cited by 53 publications

References 27 publications

Volcanism in Reverse and Strike-Slip Fault Settings

Volcanism in Reverse and Strike-Slip Fault Settings

Forearc uplift rates deduced from sediment cores of two coastal lakes in south-central Chile

Ophiolite Emplacement and the Effects of the Subduction of the Active Chile Ridge System: Heterogeneous Paleostress Regimes Recorded in the Taitao Ophiolite (Southern Chile)

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