Degree variances of the Earth's potential, topography and its isostatic compensation

1982 ◽  
Vol 56 (2) ◽  
pp. 84-94 ◽  
Author(s):  
Richard H. Rapp
Keyword(s):  
Isostatic Compensation ◽  
Degree Variances

The paradox of the axial profile: Isostatic compensation along the axis of the Mid-Atlantic Ridge?

1993 ◽  
Vol 98 (B10) ◽  
pp. 17891-17910 ◽  
Author(s):  
Gregory A. Neumann ◽  
Donald W. Forsyth
Keyword(s):  
Isostatic Compensation ◽  
Axial Profile ◽  
Mid Atlantic Ridge

Isostasy amplifies relative sea-level change on continental-scale deltas

2021 ◽  
Author(s):  
Sara Morón ◽  
Mike Blum ◽  
Tristan Salles ◽  
Bruce Frederick ◽  
Rebecca Farrington ◽  
...  
Keyword(s):  
Sea Level ◽  
Drainage Basin ◽  
Sediment Accumulation ◽  
River Mouth ◽  
Feedback Mechanism ◽  
Landscape Dynamics ◽  
Passive Margin ◽  
Sea Level Changes ◽  
Isostatic Compensation ◽  
Continental Scale

<p>The nature and contribution of flexural isostatic compensation to subsidence and uplift of passive margin deltas remains poorly understood. We performed a series of simulations to investigate flexural isostatic responses to high frequency fluctuations in water and sediment load associated with climatically-driven sea-level changes. We use a parallel basin and landscape dynamics model, BADLANDS, (an acronym for BAsin anD LANdscape DynamicS) that combines erosion, sedimentation, and diffusion with flexure, where the isostatic compensation of the load is computed by flexural compensation. We model a large drainage basin that discharges to a continental margin to generate a deltaic depocenter, then prescribe synthetic and climatic-driven sea-level curves of different frequencies to assess flexural response. Results show that flexural isostatic adjustments are bidirectional over 100-1000 kyr time-scales and mirror the magnitude, frequency, and direction of sea-level fluctuations, and that isostatic adjustments play an important role in driving along-strike and cross-shelf river-mouth migration and sediment accumulation. Our findings demonstrate that climate-forced sea-level changes set up a feedback mechanism that results in self-sustaining creation of accommodation into which sediment is deposited and plays a major role in delta morphology and stratigraphic architecture.</p>

scholarly journals Wind and turbulence measurements by the Middle and Upper Atmosphere Radar (MUR): comparison of techniques

2004 ◽  
Vol 22 (11) ◽  
pp. 3843-3862 ◽  
Author(s):  
A. A. Praskovsky ◽  
E. A. Praskovskaya ◽  
G. Hassenpflug ◽  
M. Yamamoto ◽  
S. Fukao
Keyword(s):  
Correlation Function ◽  
Momentum Flux ◽  
Signal To Noise Ratio ◽  
Spectral Width ◽  
Upper Atmosphere ◽  
Turbulent Velocity ◽  
Comparison Of Techniques ◽  
Horizontal Momentum ◽  
Degree Variances ◽  
Beam Broadening

Abstract. The structure-function-based method (referred to as UCAR-STARS), a technique for estimating mean horizontal winds, variances of three turbulent velocity components and horizontal momentum flux was applied to the Middle and Upper atmosphere Radar (MUR) operating in spaced antenna (SA) profiling mode. The method is discussed and compared with the Holloway and Doviak (HAD) correlation-function-based technique. Mean horizontal winds are estimated with the STARS and HAD techniques; the Doppler Beam Swinging (DBS) method is used as a reference for evaluating the SA techniques. Reasonable agreement between SA and DBS techniques is found at heights from 5km to approximately 11km, where signal-to-noise ratio was rather high. The STARS and HAD produced variances of vertical turbulent velocity are found to be in fair agreement. They are affected by beam-broadening in a different way than the DBS-produced spectral width, and to a much lesser degree. Variances of horizontal turbulent velocity components and horizontal momentum flux are estimated with the STARS method, and strong anisotropy of turbulence is found. These characteristics cannot be estimated with correlation-function-based SA methods, which could make UCAR-STARS a useful alternative to traditional SA techniques.

Initial Depth and Later Isostatic Compensation

2016 ◽  
pp. 21-27
Author(s):  
Charles J. Byrne
Keyword(s):  
Isostatic Compensation

Methods For Restoring and Describing Ancient Clinoform Surfaces

2018 ◽  
Vol 88 (2) ◽  
pp. 241-259 ◽  
Author(s):  
Tore Grane Klausen ◽  
William Helland-Hansen
Keyword(s):  
Depositional Environment ◽  
Sediment Load ◽  
Isostatic Compensation ◽  
Common Reference ◽  
Shelf Slope ◽  
History Of ◽  
Slope Sediment ◽  
Relative Change ◽  
Derivatives Of ◽  
3D Surfaces

Abstract Clinoform geometries demarcate a relative change from shallow to deeper waters and are therefore routinely used as paleogeography and paleobathymetry indicators. Distinct segments of the clinoform surface are defined based on their discrete breaks in slope, and these points define parameters which are used to describe and compare clinoform geometries from different basins and ages. In most cases, the breaks in slope are readily interpreted, but placement of the various breaks in slope remains mostly subjective and not strictly uniform. For clinoform geometries with gentle transitions and less accentuated breaks in slope, e.g., mud-prone systems, distinct breaks in slope can vary over many kilometers depending on selection criteria and detection method. The older and more complex history of the investigated strata, the harder it becomes to correctly place the different breaks in slope. This study proposes a common reference frame using an upper regional datum, in which the geometries of ancient clinoform surfaces can be restored. Restoration is performed with standard decompaction techniques, but we compare isostatic compensation using Airy isostasy with different scenarios of flexural support for the sediment load. Regression is used to fit a surface function to georeferenced points along the restored clinoform surface, and derivatives of this surface function are used to objectively and accurately describe and measure parameters such as relief, length, and gradient, in addition to numerically defining the bottomset, foreset, and topset segments of the clinoform surface. This enables comparison with modern counterparts unaltered by postdepositional subsidence and compaction, and the proposed procedure can be applied to 2D profiles from seismic, outcrop, or closely spaced well logs. It can also help in the analyses of 3D surfaces and the trajectory of discrete breaks in slope on successive clinoform surfaces. Accurate reconstructions and objective parameterization directly affect interpretation of shelf–slope sediment partitioning and depositional environment.

scholarly journals The Reconstruction of Former Ice Sheets and their Mass Balance Characteristics using a Non-Linearly Viscous Flow Model

1984 ◽  
Vol 30 (105) ◽  
pp. 140-152 ◽  
Author(s):  
G. S. Boulton ◽  
G. D. Smith ◽  
L. W. Morland
Keyword(s):  
Boundary Condition ◽  
Mass Balance ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Equilibrium Line Altitude ◽  
Isostatic Compensation ◽  
Geological Evidence ◽  
Wide Range ◽  
Terminal Zone ◽  
Subglacial Topography

AbstractA model of a non-linearly viscous ice sheet is used to investigate the influence of net mass-balance pattern, basal boundary condition, and subglacial topography on the size and shape of ice sheets. The aim is to enable geological evidence of the extent of former ice sheets to be used as indicators of palaeoclimate. A series of curves are presented showing the relationships between ice-sheet span, net mass balance, and equilibrium-line altitude (ELA) for zero and complete isostatic compensation. These are applicable to a very wide range of basal boundary conditions. The way in which they can be used to reconstruct net mass-balance gradients for former ice sheets is demonstrated. Changes in the basal boundary condition only have a strong influence on glacier span when they occur in the terminal zone. Ice-sheet expansion and contraction is not merely accompanied by changes in snow-line elevation, but also by changes in the net mass-balance gradient. The combinations of these required to cause ice-sheet expansion and contraction are analysed. A non-linearly viscous model for ice suggests that ice-sheet volume changes may not be a simple function of their change in areal extent.

The use of degree variances in satellite gradiometry

1997 ◽  
Vol 71 (6) ◽  
pp. 337-343 ◽  
Author(s):  
M. van Gelderen ◽  
R. Koop
Keyword(s):  
Satellite Gradiometry ◽  
Degree Variances

Isostatic compensation of tectonic features of the Mid-Atlantic Ridge: 25–27°30′S

1991 ◽  
Vol 96 (B7) ◽  
pp. 11741 ◽  
Author(s):  
Donna K. Blackman ◽  
Donald W. Forsyth
Keyword(s):  
Isostatic Compensation ◽  
Mid Atlantic Ridge ◽  
Tectonic Features
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