Book reviews     

Verna D. Freeman  R. Sinclair  Anthony M. Fuller  P. Bruyelle  Marcel Bazin  Wolf Tietze  Guido G. Weigend  K. Cehak  Werner Gallusser 《GeoJournal》1980,4(6):576-580

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Tectonic forcing of longitudinal valleys in the Himalaya: morphological analysis of the Ladakh Batholith, North India     

S. S. R. Jamieson  H. D. Sinclair  L. A. Kirstein  R. S. Purves   《Geomorphology》2004,58(1-4):49-65

Longitudinal valleys form first order topographic features in many mountain belts. They are commonly located along faults that separate tectonic zones with varying uplift histories. The Indus Valley of Ladakh, northern India, runs northwestwards following the boundary between the relatively undeformed Ladakh Batholith to the north–east and the folded and thrusted Zanskar mountains to the south–west. In this region the Shyok Valley, on the northern side of the batholith, approximately parallels the course of the Indus. This study investigates geomorphic variations in transverse catchments that drain the Ladakh Batholith, into the Indus and Shyok rivers. The batholith has been divided into three zones based on varying structural characteristics of its northeastern and southwestern boundaries. Morphometric analysis of 62 catchments that drain into the Indus and Shyok valleys was carried out using three digital datasets, and supported by field observations. Morphometric asymmetry is evident in the central zone where the Shyok valley is considered tectonically inactive, but the Indus Valley is bound by the northeastwardly thrusting Indus Molasse and the batholith. In this zone the catchments that drain into the Indus Valley are more numerous, shorter, thinner and have lower hypsometric integrals than those that drain into the Shyok. By linking these observations with the regional geology and thermochronological data it is proposed that high sediment discharge from the deformed Indus Molasse Indus Valley has progressively raised base levels in the Indus Valley and resulted in sediment blanketing of the opposing tectonically quiescent catchments that drain southwestwards off the batholith. The Indus Molasse thrust front has propagated at least 36 km towards the Ladakh Batholith over the last 20 Ma. Hence it is proposed that this long term asymmetric structural deformation and exhumation has forced the Indus longitudinal valley laterally into the Ladakh Batholith resulting in the morphometric asymmetry of its transverse catchments.  相似文献   

IGU Commission on Urban Systems and Urban Development     

Robert Sinclair 《GeoJournal》1990,21(4):418-418

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Statistical evaluation of the significance of categorical field parameters in the interpretation of regional geochemical sediment data     

P.F. Matysek  W.K. Fletcher  A.J. Sinclair 《Journal of Geochemical Exploration》1983,19(1-3)

In an attempt to study the value and utilization of categorical data collected during regional stream-sediment surveys, we have taken data from the Canadian Uranium Reconnaissance Program in S.E. British Columbia. After initial classification of the data into six subsets on the basis of catchment geology, probability plots were constructed for each of 11 elements (Zn, Cu, Pb, Ni, Co, Fe, Mn, Mo, W, Hg and U) and used to select thresholds to reject anomalous samples. The remaining background populations then were successively subdivided into groups according to their classification with respect to four sediment characteristics (abundance of fines, sand, organic matter and sediment colour) and six environmental parameters (physiography, water flow rate, stream class, drainage pattern, bank type and contamination). After calculation of log means for each group and a pooled common standard error, differences between group means were tested for significance using Duncan's Multiple Range Test. The relative degree of confidence in the significance of difference between categorical means for any single field parameter were determined using a ratio method.Results of Duncan's Multiple Range Test, show that, many field observations can be related systematically to metal content of drainage sediments. Some elements are more susceptible than others to environmental factors and some factors and some factors influence few or many elements. For example, in sediments derived from granites there are significant relationships between bank type and concentration of 8 elements (Zn, Cu, Ni, Pb, Co, Fe, Mn and Hg). In contrast, the texture of these sediments, using estimates of fines content as an index, did not significantly affect the concentration of any of the elements studied. In general, results indicate that groups of environmental factors acting collectively are more important than any single factor in determining background metal content of drainage sediments.  相似文献   

The Evidence for a Pyrenean Resurrection: a response to Babault et al. (2008)     

H. D. Sinclair  M. Gibson  G. Lynn  F. Stuart 《Basin Research》2009,21(1):143-145

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Automated detection of austere entry landing zones: A “GRAIL Tools” validation assessment     

Samantha N. Sinclair  Sally A. Shoop 《Transactions in GIS》2019,23(6):1317-1331

The Geospatial Remote Assessment for Ingress Locations (GRAIL) Tools software is a geospatial product developed to locate austere entry landing zones (LZs) for military aircraft. Using spatial datasets like land classification and slope, along with predefined LZ geometry specifications, GRAIL Tools generates binary suitability filters that distinguish between suitable and unsuitable terrain. GRAIL Tools combines input suitability filters, searches for LZs at user‐defined orientations, and plots results. To refine GRAIL Tools, we: (a) verified software output; (b) conducted validation assessments using five unpaved LZ sites; and (c) assessed input dataset resolution on outcomes using 30 and 1‐m datasets. The software was verified and validated in California and the Baltics, and all five LZs were correctly identified in either the 30 or the 1‐m data. The 30‐m data provided numerous LZs for consideration, while the 1‐m data highlighted hazardous conditions undetected in the 30‐m data. Digital elevation model grid size affected results, as 1‐m data produced overestimated slope values. Resampling the data to 5 m resulted in more realistic slopes. Results indicate GRAIL Tools is an asset the military can use to rapidly assess terrain conditions.  相似文献   

Letters to the Editor     

P. Sharma  A. J. Raudkivi  P. J. Sinclair  A. J. Raudkivi 《水文科学杂志》2013,58(3):430-440

Abstract

This work investigates historical trends of meteorological drought in Taiwan by means of long-term precipitation records. Information on local climate change over the last century is also presented. Monthly and daily precipitation data for roughly 100 years, collected by 22 weather stations, were used as the study database. Meteorological droughts of different levels of severity are represented by the standardized precipitation index (SPI) at a three-monthly time scale. Additionally, change-point detection is used to identify meteorological drought trends in the SPI series. Results of the analysis indicate that the incidence of meteorological drought has decreased in northeastern Taiwan since around 1960, and increased in central and southern Taiwan. Long-term daily precipitation series show an increasing trend for dry days all over Taiwan. Finally, frequency analysis was performed to obtain further information on trends of return periods of drought characteristics.  相似文献   

Rapid extensive erosion of the North Alpine foreland basin at 5–4 Ma     

Charlotte E. Cederbom  Peter van der Beek  Fritz Schlunegger  Hugh D. Sinclair  Onno Oncken 《Basin Research》2011,23(5):528-550

An extensive low‐temperature thermochronology study of the Swiss part of the North Alpine Foreland Basin has been conducted with the aim of deciphering the late Neogene basin development. Apatite fission‐track (AFT) ages from wells located in the distal and weakly deformed Plateau Molasse reveal rapid, km‐scale erosion with an onset in early Pliocene times. The distribution of erosion implies that there was a strong gradient in late Miocene deposition rates along the strike of the basin, with an increase towards the northeast. Additionally, renewed tectonic activity and km‐scale out‐of‐sequence thrusting during Plio‐Pleistocene times is indicated by AFT data from wells within the thrusted, proximal Subalpine Molasse. Several different mechanisms driving late Neogene basin erosion and accelerated erosional discharge from the European Alps have been considered in the literature. Based on our AFT results, we reevaluate previously published hypotheses, and suggest that a change in climate and/or drainage reorganisation coincided and possibly interacted with preexisting tectonic and geodynamic forces in the Alpine region.  相似文献   

Late Neoproterozoic–Early Paleozoic evolution of the South China Block as a retroarc thrust wedge/foreland basin system     

Baoyu Jiang  Hugh D. Sinclair  Yazhuo Niu  Jinhai Yu 《International Journal of Earth Sciences》2014,103(1):23-40

The Early Paleozoic Wuyi-Yunkai fold belt of South China represents a major orogenic belt in East Asia; however, its formation is not well understood. This paper evaluates the origins of the Neoproterozoic–Early Paleozoic basin and the southern margin of the South China Block (SCB) based on a compilation of the spatiotemporal evolution of the Late Neoproterozoic–Early Paleozoic strata and their depositional environments. These data are combined with high-resolution structural, geochronologic, metamorphic and petrologic data that are published from the region. A new model of a retroarc thrust wedge/foreland basin system is proposed for the succession based on the following: (1) the nature of the basal unconformity, (2) the wedge-shaped basin-fill geometry bounded by the mountain belt to the south, (3) basinward propagation of the thrust-front with time and (4) the presence of a typical underfilled stratigraphic trinity of the foreland basin. The proposed model suggests two major cycles of evolution of the retroarc thrust wedge/foreland basin system (<725–<635 and ca. 564–446 Ma), which record two periods of northwestward subduction of the oceanic slab beneath the southern margin of the SCB. Terrane accretion is inferred to have taken place during the late stage of these cycles.  相似文献   

A review of solar type III radio bursts     

Hamish Andrew Sinclair Reid  ;Heather Ratcliffe 《中国天文和天体物理学报》2014,(7):773-804

Solar type III radio bursts are an important diagnostic tool in the understanding of solar accelerated electron beams. They are a signature of propagating beams of nonthermal electrons in the solar atmosphere and the solar system. Consequently, they provide information on electron acceleration and transport, and the conditions of the background ambient plasma they travel through. We review the observational properties of type III bursts with an emphasis on recent results and how each property can help identify attributes of electron beams and the ambient background plasma. We also review some of the theoretical aspects of type III radio bursts and cover a number of numerical efforts that simulate electron beam transport through the solar corona and the heliosphere.  相似文献