Evolution of miocene fluvial systems in the himalayan foredeep through a two kilometer-thick succession in northern Pakistan

Willis, Brian J.

doi:10.1016/0037-0738(93)90152-u

Cited by 78 publications

(73 citation statements)

References 52 publications

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“…The reactivation surfaces and inclined co-sets that are the sedimentary evidence of down-climbing are common in modern alluvial deposits (Collinson, 1970;Jackson, 1976;Rubin and Hunter, 1982;Reesink and Bridge, 2011), in GPR images (Best et al, 2003;Lunt et al, 2004;Sambrook Smith et al, 2006Reesink et al, 2014a) and in the rock record (e.g. Jones and McCabe, 1980;Allen, 1982Allen, , 1983Haszeldine, 1982;Røe and Hermansen, 1993;Bristow, 1993b;Willis, 1993aWillis, , 1993bWillis, , 1993cMiall, 1996). Reactivation surfaces are bounding surfaces that can be associated with successive superimposed bedforms (Collinson, 1970;Allen, 1982;Miall, 1996;Reesink and Bridge, 2011).…”

Section: Climbing and Down-climbing Form-setsmentioning

confidence: 96%

Extremes in dune preservation: Controls on the completeness of fluvial deposits

Reesink

Berg

Parsons

et al. 2015

Earth-Science Reviews

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Understanding sedimentary preservation underpins our ability to interpret the ancient sedimentary record and reconstruct paleoenvironments and paleoclimates. Dune sets are ubiquitous in preserved river deposits and are typically interpreted based on a model that describes the recurrence of erosion in a vertical sequence, but without considering spatial variability. However, spatial variability in flow and sediment transport will change the recurrence of erosion, and therefore dune preservation. In order to better understand the limits of these interpretations and outline the causes of potential variability in preservation potential, this paper reviews existing work and presents new observations of an extreme end-member of dune preservation: 'form-sets', formed by dunes in which both stoss-and lee-slopes are preserved intact. These form-sets do not conform to models that are based on the recurrence of erosion, since erosion does not recur in their case, and can therefore be used to evaluate the assumptions that underpin sedimentary preservation. New Ground Penetrating Radar data from the Río Paraná, Argentina, show dune fields that are buried intact within larger scale barforms. These trains of form-sets are up to 300 m in length, are restricted to unit-bar troughs in the upper 5 m of the channel deposits, occur in N 5% of the mid-channel bar deposits, show reactivation surfaces, occur in multiple levels, and match the size of average-flow dunes. A review of published accounts of form-sets highlights a diversity of processes that can be envisaged for their formation: i) abandonment after extreme floods, ii) slow burial of abandoned dune forms by cohesive clay in sheltered bar troughs and meander-neck cut-offs, iii) fast burial by mass-movement processes, and iv) climbing of dune sets due to local dominance of deposition over dune migration. Analysis of these new and published accounts of form-sets and their burial processes highlights that form-sets need not be indicative of extreme floods. Instead, form-sets are closely associated with surrounding geomorphology such as river banks, meander-neck cut-offs, and bars because this larger-scale context controls the local sediment budget and the nature of recurrence of erosion. Locally enhanced preservation by the 'extreme' dominance of deposition is further promoted by finer grain sizes and prolonged changes in flow stage. Such conditions are characteristic, although not exclusive, of large lowland rivers such as the Río Paraná. The spatial control on dune preservation is critical: although at-a-point models adequately describe near-horizontal sets of freely migrating dunes in uniform flows, they are unsuitable for inclined dune co-sets and other cases where multiple scales of bedforms interact. Spatial and temporal variations in flow and sediment transport between the thalweg and different positions on larger bar-forms can change the preservation potential of dunes within river channels. Therefore, dune set thickness distributions are likely grouped in larger-scale un...

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Section: Climbing and Down-climbing Form-setsmentioning

confidence: 96%

Extremes in dune preservation: Controls on the completeness of fluvial deposits

Reesink

Berg

Parsons

et al. 2015

Earth-Science Reviews

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“…† Fining-upwards successions A tendency for upwards fining in bedload-dominated braided systems results from changing conditions during individual flood events and from the filling and abandonment of one channel in favour of another (e.g. Campbell 1976;Willis 1993b). An increase in discharge tends to be associated with renewed cutting of existing channels or the development of new channels.…”

Section: Eagle Mountain Formationmentioning

confidence: 99%

Observations from the Basin and Range Province (western United States) pertinent to the interpretation of regional detachment faults

Christie‐Blick

Anders

Wills

et al. 2007

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This paper summarizes the results of completed and ongoing research in three areas of the Basin and Range Province of the western United States that casts doubt on the interpretation of specific regional detachment faults and the large extensional strains with which such faults are commonly associated. Given that these examples were influential in the development of ideas about low-angle normal faults, and particularly in making the case for frictional slip at dips of appreciably less than the 308 lock-up angle for m 0.6 (where m is the coefficient of friction), we advocate a critical re-examination of interpreted detachments elsewhere in the Basin and Range Province and in other extensional and passive margin settings.The Sevier Desert 'detachment' of west-central Utah is reinterpreted as a Palaeogene unconformity that has been traced to depth west of the northern Sevier Desert basin along an unrelated seismic reflection (most probably a splay of the Cretaceous-age Pavant thrust). The absence of evidence in well cuttings and cores for either brittle deformation (above) or ductile deformation (below) is inconsistent with the existence of a fault with as much as 40 km of displacement. The Pavant thrust and the structurally higher Canyon Range thrust are erosionally truncated at the western margin of the southern Sevier Desert basin, and are not offset by the 'detachment' in the manner assumed by those inferring large extension across the basin.The Mormon Peak detachment of SE Nevada is reinterpreted as a series of slide blocks on the basis of detachment characteristics and spatially variable kinematic indicators that are more closely aligned with the modern dip direction than the inferred regional extension direction. A particularly distinctive feature of the detachment is a basal layer of up to several tens of centimetres of polymictic conglomerate that was demonstrably involved in the deformation, with clastic dykes of the same material extending for several metres into overlying rocks in a manner remarkably similar to that observed at rapidly emplaced slide blocks. The Castle Cliff detachment in the nearby Beaver Dam Mountains of SW Utah is similarly regarded as a surficial feature, as originally interpreted, and consistent with its conspicuous absence in seismic reflection profiles from the adjacent sedimentary basin.The middle Miocene Eagle Mountain Formation of eastern California, interpreted on the basis of facies evidence and distinctive clast provenance to have been moved tectonically more than 80 km ESE from a location close to the Jurassic-age Hunter Mountain batholith of the Cottonwood Mountains, is reinterpreted as having accumulated in a fluvial-lacustrine rather than alluvial fanlacustrine setting, with no bearing on either the amount or direction of tectonic transport. The conglomeratic rocks upon which the provenance argument was based are pervasively channelized, with erosional relief of less than 1 m to as much as 15 m, fining-upwards successions at the same scale and abundant trough ...

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“…The paleoenvironmental record of this study, inferred from sedimentary facies, paleosol features, and stable isotopes of carbon and oxygen in pedogenic carbonates and mammal teeth, documents substrates, vegetation, and climate over 5 myr. The Miocene flood basin was traversed by large rivers-on the scale of major tributaries to the modern Indus and Ganges-and smaller flood plain channels (18)(19)(20). Paleosol sequences of variable maturity indicate the presence of forest, woodland, and grassland vegetation that was stable for decades to thousands of years (12,14).…”

mentioning

confidence: 99%