Recent crustal movements, 1977: Whitten,C. A., Green,R. & Meade,B.K. (editors) 1979. Elsevier,Amsterdam. 633 pp. Price: hard-cover US $78.00     

P.L. Hancock 《Journal of Structural Geology》1979,1(3):256-257

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Wenlock stratigraphy and palaeogeography of Wales and the Welsh Borderland     

J.M. Hurst  N.J. Hancock  W.S. McKerrow 《Proceedings of the Geologists' Association. Geologists' Association》1978,89(3):197-226

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Petrologic constraints on rift-zone processes     

MO Garcia  RA Ho  JM Rhodes  EW Wolfe 《Bulletin of Volcanology》1989,52(2):81-96

The Puu Oo eruption in the middle of Kilauea volcano's east rift zone provides an excellent opportunity to utilize petrologic constraints to interpret rift-zone processes. Emplacement of a dike began 24 hours before the start of the eruption on 3 January 1983. Seismic and geodetic evidence indicates that the dike collided with a magma body in the rift zone. Most of the lava produced during the initial episode of the Puu Oo eruption is of hybrid composition, with petrographic and geochemical evidence of mixing magmas of highly evllved and more mafic compositions. Some olivine and plagioclase grains in the hybrid lavas show reverse zoning. Whole-rock compositional variations are linear even for normally compatible elements like Ni and Cr. Leastsquares mixing calculations yield good residuals for major and trace element analyses for magma mixing. Crystal fractionation calculations yield unsatisfactory residuals. The highly evolved magma is similar in composition to the lava from the 1977 eruption and, at one point, vents for these two eruptions are only 200 m apart. Possibly both the 1977 lava and the highly evolved component of the episode 1 Puu Oo lava were derived from a common body of rift-zone-stored magma. The more mafic mixing component may be represented by the most mafic lava from the January 1983 eruption; it shows no evidence of magma mixing. The dike that was intruded just prior to the start of the Puu Oo eruption may have acted as a hydraulic plunger causing mixing of the two rift-zone-stored magmas.  相似文献   

Book reviews     

Justin Dix  D. H. Tarling  J. H. McD Whitaker  A. J. Barber  Derek W. G. Sears  Olwen Williams-Thorpe  J. C. M. Taylor  P. L. Hancock  S. A. F. Murrell  R. B. J. Smith  Richard Stacey  S. G. Smith 《Surveys in Geophysics》1989,10(1):83-102

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Predicting earthquakes: Wyss,M. (editor) 1979. Earthquake Prediction and Seismicity Patterns. Contributions to Current Research in Geophysics,No. 8, Birkhauser,Basel. 238 pp. Price: hard-cover sFr68, DM72, US $45.     

P.L. Hancock 《Journal of Structural Geology》1980,2(4):470-471

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Wind-Tunnel Simulation of Approximately Horizontally Homogeneous Stable Atmospheric Boundary Layers     

Hancock  Philip E.  Hayden  Paul 《Boundary-Layer Meteorology》2021,180(1):5-26

Boundary-Layer Meteorology - Two cases of an overlying inversion imposed on a stable boundary layer are investigated, extending the work of Hancock and Hayden (Boundary-Layer Meteorol...  相似文献   

An experimental and computer simulation study of erosion on a mine tailings dam wall     

G. R. Hancock  G. R. Willgoose 《地球表面变化过程与地形》2004,29(4):457-475

Mine tailings dams pose a signi?cant risk to the environment if not correctly designed, built and maintained. The effect of erosion on a back‐?lled and capped earthen dam wall was examined by construction of an analogue in an experimental model landscape simulator. The ability of a computer‐based erosion model to simulate erosion processes on the experimental structure was examined. The experimental landscape simulator uses a rainfall simulator to create overland ?ow and erode an arti?cial soil. At the commencement of rainfall, erosion occurred rapidly with deep gullies developing on the dam wall batter. The gullies developed by downcutting, with consequent bank collapse and slumping, and followed ?ow lines towards their source. A physically based erosion model (SIBERIA) was used to simulate erosion on the experimental dam wall. Erosion and consequent development of the experimental structure were modelled by SIBERIA. The ability of SIBERIA to model incision and landscape development in the experimental setting was further examined by use of a simple one‐dimensional experimental catchment. The laboratory experiment and computer simulations demonstrated that erosion on the tailings dam is driven by concentrated runoff and that runoff control is crucial to the long‐term stability of such structures. The study demonstrates that computer‐based erosion models can be used to predict how erosion occurs on the experimental landscapes examined, thus providing con?dence in their use and application. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Fallout radionuclide tracers identify a switch in sediment sources and transport-limited sediment yield following wildfire in a eucalypt forest   总被引：2，自引：0，他引：2  

S.N. Wilkinson  P.J. Wallbrink  G.J. Hancock  W.H. Blake  R.A. Shakesby  S.H. Doerr 《Geomorphology》2009,110(3-4):140-151

Fire can alter sediment sources and transport rates in river basins, changing landforms and aquatic habitats and degrading downstream water quality. Variability in the response between environments, between fires, and with time since fire makes predicting the catchment-scale effect of individual fires difficult. This study applies the fallout radionuclides ¹³⁷Cs and ²¹⁰Pb_xs to trace the sources and transport of fine sediment through a river network following a wildfire of moderate to extreme severity in the 629-km² eucalypt-forested Nattai River water-supply catchment near Sydney, Australia. The tracer analysis showed that post-fire erosion caused a switch in fine (< 10 µm) sediment sources from 80% subsoil derived from gully and river bank erosion to 86% topsoil derived from hillslope surface erosion. The fine sediment phosphorus content increased 4–10 fold over pre-fire levels. Annual post-fire sediment yields estimated from suspended solids rating curves were 109–250 times higher than they would have been without fire. A large additional amount of sediment remained stored within the river network for at least four years, particularly in lower-gradient reaches. Analysis of a sediment core showed that surface erosion following a previous fire had supplied at least 29% of total catchment sediment yield over the past 36 years. It is concluded that wildfire can alter catchment sediment budgets in two ways. Firstly, a spatially-diffuse pulse of elevated erosion is associated with moderate or intense rainfall events in post-fire years. Secondly, pulses of elevated catchment sediment yield are driven by the timing and river sediment transport capacity of runoff events. Severe post-fire erosion and high interannual hydrologic variability can result in large sediment stores persisting within the river network for many years. Fallout radionuclide tracers are shown to be useful in quantifying fine sediment sources and transport dynamics following wildfire, and the contribution of wildfire to catchment sediment yield.  相似文献   

The fate of suspended sediment and particulate organic carbon in transit through the channels of a river catchment          下载免费PDF全文

Fred Worrall  Tim P. Burt  Nicholas J.K. Howden  Gregory R. Hancock  John Wainwright 《水文研究》2018,32(1):146-159

Particulate organic matter (POM) transiting through rivers could be lost to overbank storage, stored in‐channel, added to by erosion or autochthonous production, or turned over to release greenhouse gases to the atmosphere (either while in the water column or while stored in the channel). In the UK, a net loss of POM across catchments has been recorded, and the aim here was to investigate the balances of processes acting on the POM. This study considered records of suspended sediment and POM flux in comparison to stream flow, velocity, stream power, and residence time for the River Trent (English Midlands, 8,231 km²). We show that for the lower two thirds (106 km) of the River Trent, 2% is lost to overbank storage; 10% is lost to the atmosphere in the water column; and 31% is turned over while in temporary storage. Permanent in‐channel storage is negligible, and for the lower course of the river, material stored in‐channel will have a residence time of the order of hundreds of days between the last flood hydrograph of one winter and the first winter storm of the next winter (usually in the same calendar year). When considered at the scale of the UK, 1% POM in transit would be lost to overbank sedimentation; 5% turned over in the water column, and 14% turned over while in temporary storage. In the upper third of the study river channel, there is insufficient stream power to transport sediment and so in‐channel storage or in‐channel turnover over to the atmosphere dominate. The in‐channel processes of the River Trent do not conform to that expected for river channels as the headwaters are not eroding or transporting sediment. Therefore, the source of sediment must be lower down the channel network.  相似文献   

Use of fallout tracers 7Be, 210Pb and 137Cs to distinguish the form of sub‐surface soil erosion delivering sediment to rivers in large catchments          下载免费PDF全文

Gary J. Hancock  Scott N. Wilkinson  Aaron A. Hawdon  Rex J. Keen 《水文研究》2014,28(12):3855-3874

Fallout radionuclides (FRNs) ¹³⁷Cs and ²¹⁰Pb are well established as tracers of surface and sub‐surface soil erosion contributing sediment to river systems. However, without additional information, it has not been possible to distinguish sub‐surface soil erosion sources. Here, we use the FRN ⁷Be (half‐life 53 days) in combination with ¹³⁷Cs and excess ²¹⁰Pb to trace the form of erosion contributing sediment in three large river catchments in eastern Australia; the Logan River (area 3700 km²), Bowen River (9400 km²) and Mitchell River (4700 km²). We show that the combination of ¹³⁷Cs, excess ²¹⁰Pb and ⁷Be can discriminate horizontally aligned sub‐surface erosion sources (rilled and scalded hillslopes and the floors of incised drainage lines and gully ‘badland’ areas) from vertical erosion sources (channel banks and gully walls). Specifically, sub‐surface sources of sediment eroded during high rainfall and high river flow events have been distinguished by the ability of rainfall‐derived ⁷Be to label horizontal soil surfaces, but not vertical. Our results indicate that in the two northern catchments, erosion of horizontal sub‐surface soil sources contributed almost as much fine river sediment as vertical channel banks, and several times the contribution of hillslope topsoils. This result improves on source discrimination provided previously and indicates that in some areas erosion of hillslope soils may contribute significantly to sediment yield, but not as topsoil loss. We find that in north‐eastern Australia, scalded areas on hillslopes and incising drainage lines may be sediment sources of comparable importance to vertical channel banks. Previous studies have used the combination of ¹³⁷Cs, excess ²¹⁰Pb and ⁷Be to estimate soils losses at the hillslope scale. Here, we show that with timely and judicious sampling of soil and sediment during and immediately after high flow events ⁷Be measurements can augment fallout ¹³⁷Cs and ²¹⁰Pb to provide important erosion source information over large catchments. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献