A model for post‐orogenic development of a mountain range and its foreland     

G. E. Tucker  P. van der Beek 《Basin Research》2013,25(3):241-259

Decaying mountain ranges often show a surprisingly dynamic pattern of landscape evolution. Although one might expect a simple, monotonic decline in relief over time, evidence from several inactive mountain ranges shows alternating sequences of deposition and erosion in the associated basins, suggesting variations in relief and exhumation rate in the ranges themselves. Examples include the Southern Rocky Mountains, the Pyrenees, the European Alps and the Atlas Mountains. In this paper, we explore the possible origins of post‐orogenic landscape dynamics using a simple mathematical model of a mountain range and an adjacent foreland basin. The analysis highlights the importance of mass balance. In particular, a switch from basin exhumation to renewed sedimentation requires either an increase in sediment influx from the range or a decrease in sediment outflux beyond the basin margin. Although it is widely understood that post‐orogenic changes in erosion and sediment flux can have multiple causes (including climate change, regional tectonic uplift or tilting, or exhumation of variable lithologies), an important implication of our analysis is that the impact of such changes must differ in sign or magnitude between the range and the basin to be recorded. This requirement places an important constraint on viable explanations for alternating sequences of deposition and erosion in a decaying mountain‐basin pair.  相似文献   

Exploring links between vadose zone hydrology and chemical weathering in the Boulder Creek critical zone observatory     

Abigail L. Langston  Gregory E. Tucker  Robert S. Anderson  Suzanne P. Anderson 《Applied Geochemistry》2011

Understanding the relationship between subsurface flow paths on hillslopes and chemical weathering of bedrock is fundamental to understanding the timing and mechanisms that weather bedrock to saprolite. The link between chemical weathering of bedrock and contact time with reactive water along flow paths motivates this study. Water drives the chemical alteration of rock into saprolite, yet connected porosity generally declines with depth into the weathered profile. Saprolite formation, therefore, reflects coupled weathering and permeability development over time. This study uses numerical modeling and soil-moisture monitoring to explore the hydrology of the unsaturated zone and the influence of fracture density, hillslope gradient, and permeability contrasts within the saprolite development horizon on saprolite development.  相似文献   

Kinetic modeling of sodium in the lunar exosphere     

Valeriy Tenishev  Martin Rubin  Orenthal J. Tucker  Michael R. Combi  Menelaos Sarantos 《Icarus》2013

Our knowledge about the lunar environment is based on a large volume of ground-based, remote, and in situ observations. These observations have been conducted at different times and sampled different pieces of such a complex system as the surface-bound exosphere of the Moon. Numerical modeling is the tool that can link results of these separate observations into a single picture. Being validated against previous measurements, models can be used for predictions and interpretation of future observations results.  相似文献   

Breaking the 'redshift deadlock'– I. Constraining the star formation history of galaxies with submillimetre photometric redshifts     

D. H. Hughes  I. Aretxaga  E. L. Chapin  E. Gaztañaga  J. S. Dunlop  M. J. Devlin  M. Halpern  J. Gundersen  J. Klein  C. B. Netterfield  L. Olmi  D. Scott  G. Tucker 《Monthly notices of the Royal Astronomical Society》2002,335(4):871-882

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The X-Ray Telescope (XRT) for the Hinode Mission     

L. Golub  E. DeLuca  G. Austin  J. Bookbinder  D. Caldwell  P. Cheimets  J. Cirtain  M. Cosmo  P. Reid  A. Sette  M. Weber  T. Sakao  R. Kano  K. Shibasaki  H. Hara  S. Tsuneta  K. Kumagai  T. Tamura  M. Shimojo  J. McCracken  J. Carpenter  H. Haight  R. Siler  E. Wright  J. Tucker  H. Rutledge  M. Barbera  G. Peres  S. Varisco 《Solar physics》2007,243(1):63-86

The X-ray Telescope (XRT) of the Hinode mission provides an unprecedented combination of spatial and temporal resolution in solar coronal studies. The high sensitivity and broad dynamic range of XRT, coupled with the spacecraft’s onboard memory capacity and the planned downlink capability will permit a broad range of coronal studies over an extended period of time, for targets ranging from quiet Sun to X-flares. This paper discusses in detail the design, calibration, and measured performance of the XRT instrument up to the focal plane. The CCD camera and data handling are discussed separately in a companion paper.  相似文献   

Late Cretaceous India–Madagascar fit and timing of break-up related magmatism     

T.H. Torsvik  R.D. Tucker  L.D. Ashwal  L.M. Carter  B. Jamtveit  K.T. Vidyadharan  & P. Venkataramana 《地学学报》2000,12(5):220-224

A U–Pb zircon age of 91.2 ± 0.2 Myr from western India (St. Mary islands) confidently links India with the Late Cretaceous magmatic province in Madagascar (≈ 84–92 Ma), and the U–Pb age is within analytical error of the U–Pb age of the Analalava gabbro pluton (91.6 ± 0.3 Myr) in northeastern Madagascar. Palaeomagnetic data from India and Madagascar allow us to postulate a new India–Madagascar fit (Euler latitude = 14.24°, longitude = 38.8° and rotation angle = –69.2°). This fit is applicable to the Late Cretaceous, directly prior to and during the early phase of Madagascar–India separation. In our Late Cretaceous reconstruction, south-west India runs roughly subparallel with the first known break-up related magnetic anomaly (A34); it maintains a close connection between Mada-gascar and India, but places India slightly rotated compared to the eastern margin of Madagascar and more northerly compared with some reconstructions. St. Mary magmatism is linked to the initial break-up between India and Madagascar, and magmatism probably resulted from rift-related extensional processes initially induced by the Marion hotspot underlying southern Madagascar during the Late Cretaceous.  相似文献   

The effect of an offshore bank in attenuating waves     

M.J. Tucker  A.P. Carr  E.G. Pitt 《Coastal Engineering》1984,8(1):96

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A grain mobility model of post-depositional realignment   总被引：1，自引：0，他引：1  

P. Tucker 《Geophysical Journal International》1980,63(1):149-163

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Summer winds around the southern Red Sea     

Tucker  M. R.  Pedgley  D. E. 《Theoretical and Applied Climatology》1977,25(3):221-231

Theoretical and Applied Climatology - Daily synoptic maps for May–September 1966 have shown the presence of a persistent wind shift or convergence zone, the Afar Convergence Zone (ACZ),...  相似文献   

Structures and facies associated with the flow of subaerial basaltic lava into a deep freshwater lake: The Sulphur Creek lava flow, North Cascades, Washington   总被引：3，自引：2，他引：1  

David S. Tucker  Kevin M. Scott 《Journal of Volcanology and Geothermal Research》2009,185(4):311

The ca. 8800 ¹⁴C yrs BP Sulphur Creek lava flowed eastward 12 km from the Schriebers Meadow cinder cone into the Baker River valley, on the southeast flank of Mount Baker volcano. The compositionally-zoned basaltic to basaltic andesite lava entered, crossed and partially filled the 2-km-wide and > 100-m-deep early Holocene remnant of Glacial Lake Baker. The valley is now submerged beneath a reservoir, but seasonal drawdown permits study of the distal entrant lava. As a lava volume that may have been as much as 180 × 10⁶ m³ entered the lake, the flow invaded the lacustrine sequence and extended to the opposite (east) side of the drowned Baker River valley. The volume and mobility of the lava can be attributed to a high flux rate, a prolonged eruption, or both. Basalt exposed below the former level of the remnant glacial lake is glassy or microcrystalline and sparsely vesicular, with pervasive hackly or blocky fractures. Together with pseudopillow fractures, these features reflect fracturing normal to penetrative thermal fronts and quenching by water. A fine-grained hyaloclastite facies was probably formed during quench fragmentation or isolated magma-water explosions. Although the structures closely resemble those developed in lava-ice contact environments, establishing the depositional environment for lava exhibiting similar intense fracturing should be confirmed by geologic evidence rather than by internal structure alone. The lava also invaded the lacustrine sequence, forming varieties of peperite, including sills that are conformable within the invaded strata and resemble volcaniclastic breccias. The peperite is generally fragmental and clast- or matrix-supported; fine-grained and rounded fluidal margins occur locally. The lava formed a thickened subaqueous plug that, as the lake drained in the mid-Holocene, was exposed to erosion. The Baker River then cut a 52-m-deep gorge through the shattered, highly erodible basalt.  相似文献