Dispersal and Preservation of Tectonically Generated Alluvial Gravels in Sedimentary Basins

Allen, Philip A.; Heller, Paul L.

doi:10.1002/9781444347166.ch6

Cited by 30 publications

(37 citation statements)

References 107 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Sinclair et al, 1991;Kempf et al, 1999;Uba et al, 2007;Foremann et al, 2012;Allen & Heller, 2012). Sinclair et al, 1991;Kempf et al, 1999;Uba et al, 2007;Foremann et al, 2012;Allen & Heller, 2012).…”

Section: Discussionunclassified

“…Thrust front propagation at a constant rate could thus explain the change in fluvial style and the coarsening-and thickening-up trend at Napf (e.g. Temporal shifts in the sediment flux and its granuolmetric composition could also modify downsystem trends in grain size composition through differential abrasion and/or selective extraction of coarse grains from the surface flux during transport (Allen & Heller, 2012), thereby driving shifts in facies belts and thus influencing the vertical stacking pattern of sediments . This mechanism alone, however, is not capable of explaining the backstepping of alluvial megafans (Jordan & Flemings, 1991).…”

Section: Discussionmentioning

confidence: 99%

“…Accordingly, high subsidence rates paired with channel steepening will cause megafans to step back, fan gradients to increase and pebble sizes to coarsen (Flemings & Jordan, 1990;Armitage et al, 2011). In addition, depocentres in the basin centre will step back (Flemings & Jordan, 1990;Allen & Heller, 2012;Allen et al, 2013), as is documented by a shift towards a lacustrine environment in the basin farther north (Fig. In addition, depocentres in the basin centre will step back (Flemings & Jordan, 1990;Allen & Heller, 2012;Allen et al, 2013), as is documented by a shift towards a lacustrine environment in the basin farther north (Fig.…”

Section: Sedimentological and Stratigraphic Response To A Tectonic Pulsementioning

confidence: 91%

“…Most of the coarsening-and thickening upward cycles in Late Oligocene to Early Miocene Molasse deposits have been interpreted as progradation of basin margin gravels, which has commonly been related to tectonic pulses (Schlunegger et al, 1997a;Kempf et al, 1999), although we note that the ages of thrusting (Schmid et al, 1996) have been less precisely constrained than those of the inferred palaeoclimate shift (Berger, 1992;see below), and that most of the Alpine topography was built prior to 25 Ma . Allen & Heller, 2012). Allen & Heller, 2012).…”

Section: Settingmentioning

confidence: 99%

See 3 more Smart Citations

Climate vs. tectonics: the competing roles of Late Oligocene warming and Alpine orogenesis in constructing alluvial megafan sequences in the North Alpine foreland basin

Schlunegger

Norton

2014

Basin Research

View full text Add to dashboard Cite

Megafan conglomerates of foreland basins chronicle the combined effect of palaeoclimate conditions, tectonic processes and the flux and granulometric composition of the supplied sediment. However, the architecture of these deposits is seldom uniquely compatible with a single driving force. This problem is illustrated here with a field-based analysis of the ca. 30-20 Ma-old Napf deposits in the north Alpine foreland basin which are coeval with a substantial global warming of ca. 6°C during the Late Oligocene. The observed larger grain sizes and a change in fluvial style from wandering to braided could be explained climatically by a shift to drier conditions with sparse vegetation, but would have resulted in less than 400 m of additional accommodation space during the 1 Ma duration of change. Accordingly, a climate scenario alone is also not compatible with rapid sediment accumulation rates of >1000 m Ma À1 recorded at Napf, or with a lack of any remarkable shifts in the Froude number, which would be expected if water discharge patterns changed substantially. Alternatively, flexural downwarping in response to a tectonic pulse could account for the increase in grain size and the change in fluvial style from wandering (more distal facies) to braided (proximal equivalent). However, a third driving force is required to explain the contemporaneous backstepping of the distal gravel front and progradation of the proximal braided facies. We suggest that the erosional hinterland steepened in response to an inferred tectonic pulse, resulting in a more widespread exposure of lithologies with higher erosional resistance, as inferred from an increasing contribution of crystalline constituents in the clast suites. Such a change would result in a larger D 50 and a higher clast size variability in the supplied sediment, which in turn would contribute to the observed change from wandering to braided and the related shift in depositional systems. This study highlights the importance of tectonic processes and the role of changing surface lithologies in the source area for explaining variations in megafan construction even in the light of substantial palaeoclimate shift.

show abstract

Section: Discussionunclassified

Section: Discussionmentioning

confidence: 99%

Section: Sedimentological and Stratigraphic Response To A Tectonic Pulsementioning

confidence: 91%

Section: Settingmentioning

confidence: 99%

See 2 more Smart Citations

Climate vs. tectonics: the competing roles of Late Oligocene warming and Alpine orogenesis in constructing alluvial megafan sequences in the North Alpine foreland basin

Schlunegger

Norton

2014

Basin Research

View full text Add to dashboard Cite

show abstract

“…Part of the surface sediment flux in this 'cascade' is selectively sequestered at any point along the routing system to build stratigraphy, until the surface flux becomes exhausted at the downstream depositional limit (Allen 2008;Allen & Heller 2012). A mass or volume balance of the entire system allows a sediment budget to be evaluated that balances the particulate sediment derived by physical weathering against sediment volumes in depositional sinks (Clift et al 2001;Slaymaker 2003;Tinker et al 2008;Carvajal & Steel 2012;Hinderer 2012;Michael et al 2013).…”

mentioning

confidence: 99%

Erosion rates in the source region of an ancient sediment routing system: comparison of depositional volumes with thermochronometric estimates

Michael

Carter

Whittaker

et al. 2014

JGS

Self Cite

View full text Add to dashboard Cite

Calculation of the total depositional volume of an ancient source-to-sink system, combined with estimates of the area of catchments acting as source regions using provenance methods, is used to evaluate average catchment erosion rates on a million year time scale. These rates are compared with values derived from thermochronological methods. Using the mid-to late Eocene (33.9-41.6 Ma) Escanilla palaeo-sediment routing system from the south-central Pyrenean orogenic wedge-top zone as an example, c. 3500 ± 300 km 3 of solid particulate sediment was derived from two catchments in the south-central Pyrenees over a 7.7 myr period, equivalent to a mean erosion rate of c. 0.15-0.18 mm a −1 . Average exhumation rates in contributing catchments over the same time interval are estimated at 0.2-0.3 mm a −1 based on apatite fission-track analysis of pebbles in proximal conglomerates, and 0.23-0.34 mm a −1 from fission-track analysis of detrital apatites sampling a wider range of grain size. Sediment supply progressively increased during the mid-to late Eocene time period, at least in part driven by catchment expansion deep into the Pyrenean Axial Zone at c. 39 Ma. The consistency of the rates of catchment-averaged erosion calculated from different methods builds confidence that source areas have been connected to depositional sinks correctly.

show abstract

Tectonic, eustatic and climatic controls on marginal‐marine sedimentation across a flexural depocentre: Paddy Member of Peace River Formation (Late Albian), Western Canada Foreland Basin

Plint

Krawetz

Buckley

et al. 2017

The Depositional Record

View full text Add to dashboard Cite

In north‐central Alberta and adjacent British Columbia, clastic strata of the middle to late Albian Peace River and Shaftesbury formations were deposited in alluvial to shallow‐marine environments across the foredeep of the Western Canada Foreland Basin. A high‐resolution, log and core‐based allostratigraphic framework for the Paddy Member of the Peace River Formation established nine allomembers, PA to PI, bounded by flooding surfaces and apparently equivalent non‐marine surfaces. Within the estimated 2 Myr. duration of the Paddy, allomembers allow the evolving palaeogeography and changing relationship between accommodation and sedimentation rates to be analysed on time‐steps on the order of 105 years. Paddy strata fill an arcuate depocentre ca 300 km wide, across which the rocks thin eastward from 125 m to ca 5 to 10 m. The northern part of the basin is occupied by muddy, offshore marine deposits that pass abruptly southward into a linear, WSW‐ENE‐trending body of sandstone deposited in a wave‐dominated barrier‐strandplain, at least 350 km long. Extending >200 km to the south of the strandplain was a region of shallow brackish to freshwater lagoons and lakes that graded to the SW into alluvial facies. Within the lagoon region, few‐m thick, elongate and patchy sandstones represent river‐dominated deltas. In allomembers PA to PG, these sandstones are concentrated in the west and south, implying supply from the western Cordillera. In allomembers PH and PI, sandstones are mainly in the east and have a distinctive, quartz‐rich composition. They can be correlated eastward into the coeval Pelican Formation, and were sourced probably from the Canadian Shield on the opposite side of the basin. In the western foredeep, alluvial rocks comprise aggradational, unconfined floodplain deposits with ribbon sandstones, dissected, on at least nine separate levels, by palaeovalleys that are confined to the proximal foredeep. Valleys are 10 to 30 m deep, few km wide, and filled with multi‐storey channel‐bars of pebbly coarse sandstone or conglomerate. Valleys cut down from well‐developed interfluve palaeosols that record a falling and then rising water table. Alternating aggradation and degradation, and advance and retreat of the alluvial gravel front is attributed to cycles of varying rainfall intensity, rather than tectonism or eustasy. Apparently, coeval transgressive‐regressive successions in the lagoon and marine regions are attributed to few‐m scale eustatic changes. On the NE margin of the basin, tidal sandstone fills a northward‐opening estuary cut on the basal Paddy unconformity. This sandstone contains the first well‐documented specimens of Gnesioceramus comancheanus (Cragin), proving contemporaneity with at least part of the marine Joli Fou Formation to the east. Paddy allomembers change shape upward from short blunt wedges, through more acutely tapered wedges, to sheets. This change reflects initially rapid flexural subsidence, attributed to active thickening of the adjacent orogenic wedge. A waning rate of def...

show abstract

Dispersal and Preservation of Tectonically Generated Alluvial Gravels in Sedimentary Basins

Cited by 30 publications

References 107 publications

Climate vs. tectonics: the competing roles of Late Oligocene warming and Alpine orogenesis in constructing alluvial megafan sequences in the North Alpine foreland basin

Climate vs. tectonics: the competing roles of Late Oligocene warming and Alpine orogenesis in constructing alluvial megafan sequences in the North Alpine foreland basin

Erosion rates in the source region of an ancient sediment routing system: comparison of depositional volumes with thermochronometric estimates

Tectonic, eustatic and climatic controls on marginal‐marine sedimentation across a flexural depocentre: Paddy Member of Peace River Formation (Late Albian), Western Canada Foreland Basin

Contact Info

Product

Resources

About