Lateglacial and early Holocene surface exposure ages of glacial boulders in the Taiwanese high mountain range     

Robert Hebenstreit  Susan Ivy-Ochs  Peter W. Kubik  Christian Schlüchter  Margot Böse 《Quaternary Science Reviews》2011,30(3-4):298-311

Glacial landforms and sediments mapped in three presently unglaciated mountain massifs, the Nanhuta Shan, the Hsueh Shan and the Yushan, support the concept of repeated, multi-stage glaciations in the Taiwanese high mountain range during the late Pleistocene. New results from surface exposure dating using in situ produced cosmogenic ¹⁰Be measured in samples taken from erratic and moraine boulders in Nanhuta Shan at altitudes between 3100 and 3500 m are presented here. The results confirm independent and previously reported Optically Stimulated Luminescence (OSL) ages and ¹⁰Be exposure ages from glacial deposits in the same area and suggest a Lateglacial and early Holocene glaciation, the so called Nanhuta glacier advance with two substages at about 12–15 ka and 9.5 ka BP. The respective equilibrium line altitudes (ELA) were calculated at 3340 m and 3440 m with corresponding ELA depressions of 610 ± 100 m and 510 ± 100 m relative to the present day (theoretical) ELA, which is estimated to be at about 3950 ± 100 m in Taiwan. Large-scale erosional landforms indicate a much wider glacier extent during an earlier stage, which is not dated in Nanhuta Shan so far. Luminescence dating from near Hsueh Shan suggests an age of marine isotope stage (MIS) 4 for this stage.  相似文献   

Assessment of Methods and Conditions to Locate Boundaries: II. One Straight Recharge Boundary     

Robert P. Chapuis 《Ground water》1994,32(4):583-590

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The mark II Nançay radioheliograph     

J. Bonmartin  I. Jones  A. Kerdraon  A. Lacombe  M. F. Lantos  P. Lantos  C. Mercier  M. Pick  G. Trottet  M. Bruley  C. Chantelat  M. Chapuis  Y. Chapuis  B. Clavelier  C. Couteret  J. P. Drouhin  P. Gueniau  R. Tocqueville 《Solar physics》1977,55(1):251-261

We describe the new Nançay Radioheliograph (version II) which is a multicorrelator system. The main characteristics of this instrument are high space and time resolutions and flexible on-line data processing. At present it produces one-dimensional images at 169 MHz. This instrument is mainly intended for solar observations.An accurate calibration of the instrument has been carried out leading to a precise fringe stopping and to a proper knowledge of the grating response. Preliminary solar results are presented: existence of apparent motions in noise storms with a velocity of the order of 5000 km s^–1; observations of radiobursts as narrow as 0.7 (Kerdraon, 1977); observations of spikeburst activity.Presently in Sydney, Australia.  相似文献   

Shape Factors for Permeability Tests in Boreholes and Piezometers   总被引：3，自引：0，他引：3  

Robert P. Chapuis 《Ground water》1989,27(5):647-654

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Retreat dynamics of the eastern sector of the British–Irish Ice Sheet during the last glaciation     

David J. A. Evans  David H. Roberts  Mark D. Bateman  Chris D. Clark  Alicia Medialdea  Louise Callard  Elena Grimoldi  Richard C. Chiverrell  Jeremy Ely  Dayton Dove  Colm Ó Cofaigh  Margot Saher  Tom Bradwell  Steven G. Moreton  Derek Fabel  Sarah L. Bradley 《第四纪科学杂志》2021,36(5):723-751

The findings of BRITICE-CHRONO Transect 2 through the North Sea Basin and eastern England are reported. We define ice-sheet marginal oscillation between ~31 and 16 ka, with seven distinctive former ice-sheet limits (L1–7) constrained by Bayesian statistical analysis. The southernmost limit of the North Sea Lobe is recorded by the Bolders Bank Formation (L1; 25.8–24.6 ka). L2 represents ice-sheet oscillation and early retreat to the northern edge of the Dogger Bank (23.5–22.2 ka), with the Garret Hill Moraine in north Norfolk recording a significant regional readvance to L3 at 21.5–20.8 ka. Ice-marginal oscillations at ~26–21 ka resulted in L1, L2 and L3 being partially to totally overprinted. Ice-dammed lakes related to L1–3, including Lake Humber, are dated at 24.1–22.3 ka. Ice-sheet oscillation and retreat from L4 to L5 occurred between 19.7 and 17.3 ka, with grounding zone wedges marking an important transition from terrestrial to marine tidewater conditions, triggered by the opening of the Dogger Lake spillway between 19.9 and 17.5 ka. L6 relates to ice retreat under glacimarine conditions and final ice retreat into the Firth of Forth by 15.8 ka. L7 (~15 ka) represents an ice retreat from Bosies Bank into the Moray Firth.  相似文献   

A Framework for Quantitative Assessment of Impacts Related to Energy and Mineral Resource Development     

Seth S. Haines  Jay E. Diffendorfer  Laurie Balistrieri  Byron Berger  Troy Cook  Don DeAngelis  Holly Doremus  Donald L. Gautier  Tanya Gallegos  Margot Gerritsen  Elisabeth Graffy  Sarah Hawkins  Kathleen M. Johnson  Jordan Macknick  Peter McMahon  Tim Modde  Brenda Pierce  John H. Schuenemeyer  Darius Semmens  Benjamin Simon  Jason Taylor  Katie Walton-Day 《Natural Resources Research》2014,23(1):3-17

Natural resource planning at all scales demands methods for assessing the impacts of resource development and use, and in particular it requires standardized methods that yield robust and unbiased results. Building from existing probabilistic methods for assessing the volumes of energy and mineral resources, we provide an algorithm for consistent, reproducible, quantitative assessment of resource development impacts. The approach combines probabilistic input data with Monte Carlo statistical methods to determine probabilistic outputs that convey the uncertainties inherent in the data. For example, one can utilize our algorithm to combine data from a natural gas resource assessment with maps of sage grouse leks and piñon-juniper woodlands in the same area to estimate possible future habitat impacts due to possible future gas development. As another example: one could combine geochemical data and maps of lynx habitat with data from a mineral deposit assessment in the same area to determine possible future mining impacts on water resources and lynx habitat. The approach can be applied to a broad range of positive and negative resource development impacts, such as water quantity or quality, economic benefits, or air quality, limited only by the availability of necessary input data and quantified relationships among geologic resources, development alternatives, and impacts. The framework enables quantitative evaluation of the trade-offs inherent in resource management decision-making, including cumulative impacts, to address societal concerns and policy aspects of resource development.  相似文献   

The mixed-bed glacial landform imprint of the North Sea Lobe in the western North Sea     

David H. Roberts  Elena Grimoldi  Louise Callard  David J.A. Evans  Chris D. Clark  Heather A. Stewart  Dayton Dove  Margot Saher  Colm Ó Cofaigh  Richard C. Chiverrell  Mark D. Bateman  Steven G. Moreton  Tom Bradwell  Derek Fabel  Alicia Medialdea 《地球表面变化过程与地形》2019,44(6):1233-1258

During the last glacial cycle an intriguing feature of the British-Irish Ice Sheet was the North Sea Lobe (NSL); fed from the Firth of Forth and which flowed south and parallel to the English east coast. The controls on the formation and behaviour of the NSL have long been debated, but in the southern North Sea recent work suggests the NSL formed a dynamic, oscillating terrestrial margin operating over a deforming bed. Further north, however, little is known of the behaviour of the NSL or under what conditions it operated. This paper analyses new acoustic, sedimentary and geomorphic data in order to evaluate the glacial landsystem imprint and deglacial history of the NSL offshore from NE England. Subglacial tills (AF2/3) form a discontinuous mosaic interspersed with bedrock outcrops across the seafloor, with the partial excavation and advection of subglacial sediment during both advance and retreat producing mega-scale glacial lineations and grounding zone wedges. The resultant ‘mixed-bed’ glacial landsystem is the product of a dynamic switch from a terrestrial piedmont-lobe margin with a net surplus of sediment to a partially erosive, quasi-stable, marine-terminating, ice stream lobe as the NSL withdrew northwards. Glaciomarine sediments (AF4) drape the underlying subglacial mixed-bed imprint and point to a switch to tidewater conditions between 19.9 and 16.5 ka cal BP as the North Sea became inundated. The dominant controls on NSL recession during this period were changing ice flux through the Firth of Forth ice stream onset zone and water depths at the grounding line; the development of the mixed-bed landsystem being a response to grounding line instability. © 2018 John Wiley & Sons, Ltd.  相似文献   

Numerical values of shape factors for field permeability tests in unconfined aquifers     

Zhang  Lu  Chapuis  Robert P.  Marefat  Vahid 《Acta Geotechnica》2020,15(5):1243-1257

Acta Geotechnica - Field permeability tests are used to evaluate the local hydraulic conductivity. Their interpretation requires knowing the value of a shape factor, c. Regular values for shape...  相似文献