This more youthful celebration is localized in the geographical level associated with the La Grange error

This more youthful celebration is localized in the geographical level associated with the La Grange error

Rachel Piotraschke, Susan M. Cashman, Kevin P. Furlong, Peter J.J. Kamp, e they on Siletzia?. Lithosphere 2015;; 7 (4): 427a€“440. doi:

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Abstract

The Klamath hills state of northwestern Californiaa€“southwestern Oregon is actually an anomalous aspect in the Cascadia margin; these hills possess greatest typical geography, the earliest rocks, in addition to merely determined exemplory instance of belated Cenozoic detachment faulting within the coastal mountains for the Cascadia forearc. Low-temperature thermochronology (apatite fission-track, apatite [U-Th]/the guy) analyses through the central and south Klamath Mountains state record two specific exhumation events-a Cretaceousa€“Paleocene local cooling and a southward-migrating locus of quick cooling/exhumation in the middle Tertiary. We infer that this design reflects two distinct processes of exhumation: regional exterior erosion (older) and moving localized tectonic exhumation (younger). At southern limitation for this area for rapid cooling, slickenside striations from the revealed La Grange failing exterior record southward displacement with the top dish along a shallowly dipping (a??20A°) detachment area. Thermochronologic information constrain typical plunge regarding the fault to a few qualifications, upper-plate width to

INTRODUCTION

The Klamath Mountain state (Fig. 1) straddles a simple transition for the the united states dish border from subduction along Cascadia to interpretation across the San Andreas program, which is both geologically and topographically distinct. The orogen’s Neogene to Holocene tectonic records probably produces a window in to the evolution on the dish boundary since it underwent the transition from a lengthy reputation for subduction (Farallon, Juan de Fuca) to encroaching translational (Pacific) dish connections. The Klamath hill province currently has a number of the greatest topography across the convergent border (Fig. 1A). Optimal and indicate elevations into the Klamath hills is higher than those elsewhere inside seaside range of Cascadia (Kelsey et al., 1994), in addition to Klamath hill state, consisting of Precambrian to Late Cretaceous, primarily oceanic tectonostratigraphic terranes, includes the earliest (Wallin et al., 1995) and among the most structurally complex (cf. Irwin, 1981, 1985) devices along side Cascadia margin. The time when this highest geography developed additionally the connection between uplift and exhumation of Paleozoic and Mesozoic bedrock stays not clear.

Effective distortion inside southernmost Cascadia subduction area, on latitude regarding the Klamath Mountains province, in addition varies from that https://datingmentor.org/sugar-daddies-uk/ other Cascadia margin.

Patterns of seismicity, including the spatial and temporary circulation of episodic tremor and slide events (Fig. 1A; Szeliga et al., 2004; Brudzinski and Allen, 2007; Gomberg et al., 2010; K. Creager, , personal commun.), anticorrelation of tremor and tiny upper-plate earthquakes (Boyarko and Brudzinski, 2010; Gomberg et al., 2010), and inferred segmentation of Cascadia subduction area earthquake record (age.g., Wang et al., 2013), all distinguish the southern part of the Cascadia subduction area.

(1) do the Klamath topographic massif mirror relict (Late Cretaceousa€“Early Tertiary) geography, or is they a direct result young and/or ongoing uplift for this modern plate border?

(2) perform some distinctive seismologic traits for the southernmost Cascadia subduction zone margin echo the geologic dynamics of the local forearc (e.g., crust from the Klamath hill province), or are they just a function of the existing plate-tectonic style separate of upper-plate crustal framework?

Within this paper, we existing brand new low-temperature thermochronologic facts from the main and southeastern Klamath hills, make use of these to constrain the action reputation of a regionally big failing (the Los Angeles Grange error), and determine their ramifications when it comes down to Cenozoic tectonic evolution for the Klamath hills province. With brand-new thermochronometry facts, we taste previous interpretations of Cenozoic reputation for the Klamath region, e.g., Neogene Condrey hill dome (Mortimer and Coleman, 1985) and Klamath peneplain (Diller, 1902; Aalto, 2006). We next talk about the spatial and temporary correspondence between mid-Cenozoic tectonic events from inside the Klamath Mountains province in addition to accretion on the Siletz terrane inside the Oregon Coast Ranges (Wells et al., 2014). We determine that Cenozoic tectonism into the Klamath Mountains state had been connected to happenings on the Cascadia margin towards the north.

2022-02-20T09:05:48+00:00