摘要:

AbstractCO2concentrations at depths of 15,30, and 50 cm were determined over a one‐year period in six karst soils in the Malay peninsula. Evidence suggests that the highest single CO2value (MAXCO2, per cent) recorded at each site/depth provides the best estimate of conditions during groundwater recharge events. Soil depth (cm) and bulk density (BDEN) are the best predictors of MAXCO2, with the equation loglo(MAXCO2) = 1·146 (BDEN) + 0·00698 (DEPTH) ‐ 1·227 accounting for 86 per cent of the variation. This equation is used to model MAXCO2at seven, more remote sites. Soil throughflow patterns and groundwater recharge points are estimated from slope pantometer and soil depth surveys in order to assess the CO2concentration with which soil waters ultimately equilibrate before entering the limestone. Limestone weathering seems to be predominantly of the open system type, the overall mean MAXCO2of 1·65 per cent corresponding with a weathering potential of 167 ppm CaCO3. Weathering potentials vary markedly, ranging from 62–82 ppm on rocky hilltops to more than 280 ppm on certain tower karst footslopes in Selangor and the Kinta Valley and on moderate hillslopes developed in impure limestones in the Bound

ISSN:0197-9337    

DOI:10.1002/esp.3290090502

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractSpindle‐ and parabolic‐shaped drumlins examined at fifty‐five localities in northern Ireland possess stratification sequences on their lee‐side flanks. These forms lack the distinctive steep stoss‐ and tapering lee‐ends of classical drumlins and tend to occur in linear zones transverse to late Pleistocene ice‐flow. In most cases (90 per cent) the stratified deposits infill embayments excavated in the lee‐side of barkhanoid forms and, in the remainder (10 per cent), they are superimposed on the lee‐side of whaleback forms. The stratification sequences developed as a result of sedimentation in interconnected subglacial water‐filled cavities and are unlike remanie proglacial sediments moulded by ice into drumlin form. Stratigraphic evidence indicates that the lee‐side sequences developed during drumlin streamlining, which supports the view that subglacial hydraulic processes played an important role

ISSN:0197-9337    

DOI:10.1002/esp.3290090503

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractDesert varnish occurs in arid western New South Wales. Microprobe analysis has shown that the chemical composition of this varnish lies within the ranges reported for varnish in United States. Field observations suggest that desert varnish near the soil surface may be destroyed by weathering, but that varnish at depths of more than 15 cm can survive burial and later be exhumed. Varnish has also survived coating by calcium carbonate; a corrected age of about 5000 years for the carbonate indicates long‐term persistence of varnish under this form of ‘burial’. In some situations, presently‐exposed varnish may have a complex history of burial and exhumation following initial subaerial fo

ISSN:0197-9337    

DOI:10.1002/esp.3290090504

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper represents a systematic investigation of slope evolution diffusion models and has the following sections: (1) The model of slope development with linear coefficientk=k0x; (2) The model of slope development with quadratic coefficient inx; (3) Slope development model with vertical lowering of base level (downcutting); (4) Slope development model with the base level a horizontal variable (undercutting); (5) Steady‐state regime of undercut slopes; (6) Model of a pediment and scree slope formation.The comparison is made between mathematical and classical methods of slope evolution analysi

ISSN:0197-9337    

DOI:10.1002/esp.3290090505

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper investigates the reasons for the presence of both domed inselbergs (bornhardts) and boulder inselbergs (koppies) on the Matopos Batholith, Zimbabwe. XRF and microprobe analyses of rock samples from 16 bornhardts and 24 koppies have shown no significant chemical or mineralogical differences which might indicate greater weathering resistance of the bornhardts. Many bornhardts are located on massive bodies of slowly‐cooled porphyritic granite which were emplaced at a relatively late stage in the evolution of the batholith. The surrounding rocks are less porphyritic and appear to have been foliated during deformation associated with emplacement of the later bodies. The entire batholith has been affected by post‐emplacement tectonism which has created three major fracture systems. The morphological differences between bornhardts and koppies in this area are therefore considered to reflect differences in jointing which arise both from the primary igneous emplacement process and from tectonic deformat

ISSN:0197-9337    

DOI:10.1002/esp.3290090506

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractSmall scale features resulting from wind erosion are widespread in the Namib Desert. They include selective erosion of lithological variations (etching), flutes and grooves, facetting of clasts and residual boulders, and smoothing and polishing of rock surfaces. Large scale features are tentatively identified and are restricted to the southern Namib, with its high energy, unidirectional wind regime.Wind erosion features are best developed on fine‐grained rocks of intermediate hardness. They are oriented towards or parallel to modern strong winds.The turbulent flow of wind armed only with dust particles is probably more important than wind driven sand in creating smooth polished rock surfaces, flutes, and grooves. Wind driven sand appears to be significant only in facetting rock masse

ISSN:0197-9337    

DOI:10.1002/esp.3290090507

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe oxygen plasma furnace enables small samples of clastic sediment to be separated from filter papers at low temperatures without physical or chemical alteration of the sediment. This technique provides a suitable treatment for processing very small samples of alpine eolian sediment, enabling their grain size distribution, mineralogy, and origin to be determined.

ISSN:0197-9337    

DOI:10.1002/esp.3290090508

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe River Severn, near Shrewsbury, Shropshire, England, is formed by the union of the uppermost Severn with the Vyrnwy; both of these major headstreams drain from the Welsh upland. That part of the trunk Severn here under consideration has been under investigation for some years as exemplifying Osage‐type underfitness. In the course of the investigation, a census was made of width between banktops on two reaches, and of water surface width on one of these reaches: the difference between the two types of width gives the value of a third type, the width of batter. All three width types produce Poisson distributions of frequency. Width, particularly width between banktops, varies rapidly in the downstream direction. In view of the observed Poisson distributions, transform rather than arithmetic values have been used in difference‐of‐means tests applied to variation along the channel: cube root transforms are the type selected. Although there is little to choose, on the study reaches, between arithmetic means and Poisson modes, the results obtained do suggest a query about the selection of the most appropriate width values, for instance for the purposes of channel morphology. All types of width are found to vary along the channel far more rapidly than would be expected from mere randomness. Variation in bank strength appears to account for about half the variation in width between banktops. The results obtained for batter width could be applied in the design of a sampling programme designed to identify local difference in bank str

ISSN:0197-9337    

DOI:10.1002/esp.3290090509

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractSeparation of rill and inter‐rill erosion is required in many of the soil erosion models currently being developed. The feasibility of basing the separation on the hydraulic properties of the flow and resultant sediment production is examined in a laboratory simulation of rill initiation and development. Four stages are identified in the process of rill formation; these are sheetflow, flowline development, micro‐rills, and micro‐rills with headcuts. There are significant differences in terms of flow characteristics between the stages, especially between sheetflow and flowlines, indicating the promise of this method for making a more precise distinction between rill and inter‐rill

ISSN:0197-9337    

DOI:10.1002/esp.3290090510

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0197-9337    

DOI:10.1002/esp.3290090501

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY