Tectonics of the Neogene Cascadia forearc basin: Investigations of a deformed late Miocene unconformity

McNeill, L. C.; Goldfinger, Chris; Kulm, L. D.; Yeats, Robert S.

doi:10.1130/0016-7606(2000)112<1209:totncf>2.0.co;2

Cited by 75 publications

(70 citation statements)

References 38 publications

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“…This implies that the India-Asia collision took place after deposition of the Jialazi Formation (i.e., after 54 Ma), as favored by the paleomagnetic study in the same area by Meng et al (2012). According to this interpretation, the supposedly angular unconformity between the Qubeiya and Quxia formations and the sedimentological changes within the Quxia and Jialazi formations must have resulted from changes in the dynamics of Neo-Tethyan oceanic subduction, as other unconformities documented in forearc basins worldwide (e.g., Neogene Cascadia forearc in western North America; McNeill et al, 2000; Cretaceous Yezo forearc in Japan; Ando and Tomosugi, 2005). The Qubeiya/Quxia unconformity, corresponding to a time gap potentially including much of Paleocene time (66-58 Ma), may be correlated with the angular unconformity between strongly deformed Mesozoic strata and overlying Linzizong volcanic succession in south Tibet (Burg et al, 1983;He et al, 2007;Mo et al, 2008).…”

Section: Paleogeographic Modelmentioning

confidence: 84%

New insights into the timing of the India – Asia collision from the Paleogene Quxia and Jialazi formations of the Xigaze forearc basin, South Tibet

et al. 2016

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Section: Paleogeographic Modelmentioning

confidence: 84%

New insights into the timing of the India – Asia collision from the Paleogene Quxia and Jialazi formations of the Xigaze forearc basin, South Tibet

et al. 2016

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“…Previous landmark studies have clearly shown how the magmatic arc-forearc basin-accretionary prism forms a trinity that characterizes the upper plate of most convergent margins (e.g., Dickinson, 1974Dickinson, , 1976Dickinson and Seeley, 1979;Ingersoll, 1982Ingersoll, , 1983. Many forearc basin studies have focused on the interplay between arc magmatism, accretionary prism exhumation, and sediment deposition in forearc basins (e.g., Dickinson, 1995;Busby et al, 1998;Clift et al, 2000;McNeill et al, 2000;Kimbrough et al, 2001;DeGraaff-Surpless et al, 2002;Unruh et al, 2007;Fildani et al, 2008;Trop, 2008). These studies provide an important framework for evaluating the development and stratigraphy of forearc regions that are characterized by long-lived subduction of "normal" oceanic crust.…”

Section: Discussionmentioning

confidence: 99%

Modification of Continental Forearc Basins by Flat‐Slab Subduction Processes: A Case Study from Southern Alaska

Ridgway

Trop

Finzel

2011

Tectonics of Sedimentary Basins

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Forearc basins are large sediment repositories that develop in the upper plate of convergent margins and are a direct response to subduction. These basins are part of the magmatic arc-forearc basin-accretionary prism "trinity" that defines the tectonic configuration of the upper plate along most subduction-related convergent margins. Many previous studies of forearc basins have explored the links between construction of magmatic arcs, exhumation of accretionary prisms, and sediment deposition in adjacent forearc basins. These studies provide an important framework for understanding firstorder tectonic processes recorded in forearc basins that are characterized by long-lived subduction of "normal" oceanic crust. Many convergent margins, however, are complicated by second-order subduction processes, such as flat-slab subduction of buoyant oceanic crust in the form of seamounts, spreading and aseismic ridges, and oceanic plateaus. These second-order processes can substantially modify the tectonic configuration of the upper plate both in time and space, and produce sedimentary basins that do not easily fit into the conventional magmatic arc-forearc basin-accretionary prism trinity.In this chapter, we discuss the modification of the southern Alaska forearc basin by Paleocene-Eocene subduction of a spreading ridge followed by OligoceneHolocene subduction of thick oceanic crust. This thick oceanic crust is currently being subducted beneath south-central Alaska and has an imaged maximum thickness of 30 km at the surface and 22 km at depth. Findings from southern Alaska suggest that forearc basins modified from flat-slab subduction processes may contain a sedimentary and volcanic stratigraphic record that differs substantially from typical forearc basins. Processes and sedimentary features that characterize modified forearc basins include the following: (1) flat-slab subduction of a buoyant, topographically elevated spreading ridge oriented subparallel to the margin prompts diachronous uplift of the forearc basin floor and exhumation of older marine forearc basin strata as the ridge is subducted. Passage of the spreading ridge leads to subsidence and renewed deposition of nonmarine sedimentary and volcanic strata that locally exceeds the thickness of the underlying marine strata. (2) Insertion of a slab window beneath the forearc basin during spreading ridge subduction produces local intrabasinal topographic highs with adjacent depocenters, as well as discrete volcanic centers within and adjacent to the forearc basin. (3) Flat-slab subduction of thick oceanic crust also results in surface uplift and exhumation of forearc basin sedimentary strata. However, the insertion of thick crust throughout the flat-slab region (i.e., lack of a slab window) inhibits subduction-related magmatism adjacent to the forearc basin. In the case of subduction of a >350-km-wide fragment of thick oceanic crust beneath south-central Alaska, exhumation of forearc basin strata located above the region of flat-slab subduction has prompted enhanced T...

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“…5 (supported by leveling and tide gauge data) suggests that broad regions of the upper plate where the stress line swings landward coincide with major structural uplifts. The central Oregon region where the stress line swings seaward coincides with a deep structural and gravity low (McNeill et al 2000). In Oregon, two of the structural uplifts correspond to free-air gravity highs and are known as Coquille, and Heceta Banks, while the third Nehalem Bank, is a gravity low ( Fig.…”

Section: Interplate Coupling At Forearc Basins and Banksmentioning

confidence: 98%

“…5). We used the youngest structures available, though only approximate temporal control is available from a few test wells (McNeill et al 2000). Note that evidence of extension of the Washington shelf shown in Fig.…”

Section: Down-dip Limit Of Interplate Couplingmentioning

confidence: 99%

Confidence levels for tsunami-inundation limits in northern Oregon inferred from a 10,000-year history of great earthquakes at the Cascadia subduction zone

et al. 2009

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To explore the local tsunami hazard from the Cascadia subduction zone we (1) evaluate geologically reasonable variability of the earthquake rupture process, (2) specify 25 deterministic earthquake sources, and (3) use resulting vertical coseismic deformations for simulation of tsunami inundation at Cannon Beach, Oregon. Maximum runup was 9-30 m (NAVD88) from earthquakes with slip of *8-38 m and M w *8.3-9.4. Minimum subduction zone slip consistent with three tsunami deposits was 14-15 m. By assigning variable weights to the source scenarios using a logic tree, we derived percentile inundation lines that express the confidence level (percentage) that a Cascadia tsunami will not exceed the line. Ninety-nine percent of Cascadia tsunami variation is covered by runup B30 m and 90% B16 m with a ''preferred'' (highest weight) value of *10 m. A hypothetical maximum-considered distant tsunami had runup of *11 m, while the historical maximum was *6.5 m.

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Tectonics of the Neogene Cascadia forearc basin: Investigations of a deformed late Miocene unconformity

Cited by 75 publications

References 38 publications

New insights into the timing of the India – Asia collision from the Paleogene Quxia and Jialazi formations of the Xigaze forearc basin, South Tibet

New insights into the timing of the India – Asia collision from the Paleogene Quxia and Jialazi formations of the Xigaze forearc basin, South Tibet

Modification of Continental Forearc Basins by Flat‐Slab Subduction Processes: A Case Study from Southern Alaska

Confidence levels for tsunami-inundation limits in northern Oregon inferred from a 10,000-year history of great earthquakes at the Cascadia subduction zone

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