Chronology and rates of faulting of Ventura River terraces, California

Rockwell, T. K.; Keller, Edward A.; Clark, Michael N.; Johnson, Donald L.

doi:10.1130/0016-7606(1984)95<1466:carofo>2.0.co;2

Cited by 141 publications

(89 citation statements)

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“…Various authors have shown therefore that some information on the rate of tectonic processes may be retrieved from a geomorphological approach. For example, the geometry of marine terraces [e.g., Lajoie, 1986;Armijo et al, 1996] or of fluvial terraces [e.g., Rockwell et al, 1984;Bull and Knuepfer, 1987;Merritts et al, 1994] may be used to derive rates of tectonic uplift or paleoclimatic conditions) are poorly constrained or vary simultaneously. The problem has therefore also been tackled using numerical modeling [Koons, 1989;Chase, 1992;Lifton and Chase, 1992;Willgoose, 1994].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the relationships between basin morphology, tectonic uplift, and denudation from the study of an active fold belt in the Siwalik Hills, central Nepal

Hurtrez¹,

Lucazeau²,

Lavé³

et al. 1999

J. Geophys. Res.

130

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Abstract. The present study investigates correlations between an extensive range of geomorphic properties that can be estimated from a digital elevation model and the uplift rate on geological timescales. The analysis focuses on an area in the Siwalik Hills (central Nepal), where lithology and climate can be considered as uniform. This area undergoes rapid tectonic uplift at rates of up to 15 mm yr -•, which are derived from the geometric pattern of a faultbend model of fold growth. The selected geomorphic properties can be divided in two categories, depending on whether or not the vertical dimension is taken into account. None of the planar properties are significantly correlated to uplift rate, unlike those that include the vertical dimension, such as the mean elevation of basins, hypsometric curve, and hypsometric integral, and relief defined by the amplitude factor of length scaling analysis. Correlation between relief and uplift rate is observed for all length scales of topography shorter than 600 m, which suggests that all orders of the streams are able to adjust to the tectonic signal. Simple mass balance considerations imply that the average elevation is only 10% of surface uplift, suggesting that a dynamic equilibrium has been reached quite rapidly. Using a simple two-process model for erosion, we find that fairly high diffusion coefficients (order of 10 m 2 yr -•) and efficient transport of the material by rivers are required. This unusually high value for mass diffusivity at small length scales may be obtained by either a very efficient linear diffusion or by landsliding. Actually, both processes may be active, which appears likely given the nature of the unconsolidated substratum and the favorable climatic conditions. Local relief in the study area may therefore be used to predict either uplift or denudation, but the prediction is calibrated only for that specific climatic and lithologic conditions and cannot be systematically applied to other contexts.

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Section: Introductionmentioning

confidence: 99%

Investigation of the relationships between basin morphology, tectonic uplift, and denudation from the study of an active fold belt in the Siwalik Hills, central Nepal

Hurtrez¹,

Lucazeau²,

Lavé³

et al. 1999

J. Geophys. Res.

130

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“…A convenient and straightforward hypothesis is to assume that the straths were initially similar to the modern channel. Accordingly, the incision, measured from the difference in elevation between the terrace remnants and the modern river bed, is considered as a proxy for tectonic uplift [Iwata et al, 1984;Molnar, 1987;Rockwell et al, 1984;Burbank et al, 1996]. If the various terrace levels have developed at times of fluvial regimes different from the present, change of the river geometry may have occurred and must be accounted for, since they can be sources of differential incision not related to uplift.…”

Section: B1 Principlesmentioning

confidence: 99%

Active folding of fluvial terraces across the Siwaliks Hills, Himalayas of central Nepal

Lavé¹,

Avouac²

2000

J. Geophys. Res.

862

712

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Abstract. We analyze geomorphic evidence of recent crustal deformation in the subHimalaya of central Nepal, south of the Kathmandu Basin. The Main Frontal Thrust fault (MFT), which marks the southern edge of the sub-Himalayan fold belt, is the only active structure in that area. Active fault bend folding at the MFT is quantified from structural geology and fluvial terraces along the Bagmati and Bakeya Rivers. Two major and two minor strath terraces are recognized and dated to be 9.2, 2.2, and 6.2, 3.7 calibrated (cal) kyr old, respectively. Rock uplift of up to 1.5 cm/yr is derived from river incision, accounting for sedimentation in the Gangetic plain and channel geometry changes. Rock uplift profiles are found to correlate with bedding dip angles, as expected in fault bend folding. It implies that thrusting along the MFT has absorbed 21 _+ 1.5 mm/yr of N-S shortening on average over the Holocene period. The +1.5 mm/yr defines the 68% confidence interval and accounts for uncertainties in age, elevation measurements, initial geometry of the deformed terraces, and seismic cycle. At the longitude of Kathmandu, localized thrusting along the Main Frontal Thrust fault must absorb most of the shortening across the Himalaya. By contrast, microseismicity and geodetic monitoring over the last decade suggest that interseismic strain is accumulating beneath the High Himalaya, 50-100 km north of the active fold zone, where the Main Himalayan Thrust (MHT) fault roots into a ductile d•collement beneath southern Tibet. In the interseismic period the MHT is locked, and elastic deformation accumulates until being released by large (M w > 8) earthquakes. These earthquakes break the MHT up to the near surface at the front of the Himalayan foothills and result in incremental activation of the MFT.

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“…Fluvial terraces can be used to record a river's response to differential uplift along or across faults and folds (Keller et al, 1982;Burnett and Schumm, 1983;Rockwell et al, 1984;Pazzaglia and Gardner, 1993;Personius et al, 1993;Merritts et al, 1994;Molnar et al, 1994;Nicol et al, 1994;Personius, 1995;Burbank et al, 1996;Lavé and Avouac, 2000). In the last 20 years, the role of fluvial terraces in neotectonic studies has expanded from a passive geomorphic marker that records fault displacement in paleoseismic studies to strain markers used to infer underlying fold geometries in the substrate (Molnar et al, 1994;Lavé and Avouac, 2000).…”

Section: Introductionmentioning

confidence: 99%

River response to an active fold-and-thrust belt in a convergent margin setting, North Island, New Zealand

et al. 2003

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High-resolution digital elevation data (TOPSAR 10-m grid) are used to reconstruct Late Quaternary growth histories of subtle folding in the Wairarapa fold-and-thrust belt, North Island, New Zealand. Outcrop data of deformed latest Miocene and younger strata are combined with observations of warped and faulted late Quaternary terrace surfaces to unravel the geomorphic and structural history of the Huangarua River valley. Optically stimulated luminescence (OSL) dating of loess that accumulated on these strath terraces and paleosol stratigraphy allow temporal correlation among the terraces and with glacial climate cycles since the Last Interglaciation. These data indicate that five intervals of strath cutting occurred, at f 125, 60 -70, f 30, f 15, and < 10 ka. Strath beveling is largely independent of local folding or regional base-level change. We hypothesize that straths are cut when an increase in sediment supply, during cool climatic periods, brings river sediment load and river transport capacity into balance. In the Wairarapa, strath-cutting events appear to occur near the end of cool climatic cycles.This study shows that the identification of subtle departures from regional topographic trends becomes practical when a high-resolution DEM is available. After subtraction of an average valley gradient from the digital topography, the residual topography on the terrace treads reveals cross-valley and longitudinal tilting. Although rates of folding are slow and the magnitude of deformation is commonly limited to less than a few tens of meters, these topographic anomalies define fold axes that coincide with subsurface structures. When combined with time control, these anomalies serve to define the patterns and rates of fold growth over the past 125 kyears. D

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Chronology and rates of faulting of Ventura River terraces, California

Cited by 141 publications

References 0 publications

Investigation of the relationships between basin morphology, tectonic uplift, and denudation from the study of an active fold belt in the Siwalik Hills, central Nepal

Investigation of the relationships between basin morphology, tectonic uplift, and denudation from the study of an active fold belt in the Siwalik Hills, central Nepal

Active folding of fluvial terraces across the Siwaliks Hills, Himalayas of central Nepal

River response to an active fold-and-thrust belt in a convergent margin setting, North Island, New Zealand

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