Related Experiment Video
Updated: Jan 25, 2026
14:48
Generation of Dynamical Environmental Conditions using a High-Throughput Microfluidic Device
Published on: April 17, 2021
4.5K
Ice-stream demise dynamically conditioned by trough shape and bed strength
Tom Bradwell1,2, David Small3, Derek Fabel4
1Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK.
Science Advances
|May 7, 2019
Summary
Glacial ice stream retreat was significantly influenced by bed strength and trough shape, not just external factors. A transition from weak to strong beds around 18,500 years ago triggered rapid ice-stream demise.
Area of Science:
- * Glaciology and Paleoclimatology
- * Ice Sheet Dynamics
Background:
- * Ice sheet mass loss is primarily driven by fast-flowing glaciers (ice streams) that terminate in the ocean.
- * Understanding long-term ice-stream flow, retreat, and the influence of bed topography and strength is crucial for predicting future ice loss.
Purpose of the Study:
- * To reconstruct the retreat history and grounding-line movements of a former ice stream over the past 15,000 years.
- * To investigate the role of geological factors, specifically bed shape and substrate, in controlling ice-stream behavior.
Main Methods:
- * Analysis of a former ice stream with known or definable trough geometry and bed substrate.
- * Reconstruction of ice-stream retreat and grounding-line migration since the Last Glacial Maximum.
Main Results:
- * A significant behavioral shift in ice-stream retreat occurred between 18,500 and 16,000 years ago.
- * This shift, independent of external forcing, correlated with the collapse of floating ice sectors and rapid ice-front retreat.
- * The event was linked to a geological transition from a soft/weak bed to a hard/strong bed, coupled with changes in trough geometry.
Conclusions:
- * Geological factors, including bed strength and trough shape, played a critical role in the demise of the studied ice stream.
- * These factors conditioned and accelerated ice-stream retreat, highlighting their importance in past and potentially future ice sheet behavior.
Related Concept Videos
01:19Role of Shaping in Operant Conditioning
987
Shaping is a technique used in operant conditioning to train complex behaviors by rewarding successive approximations toward the target behavior. This method is necessary because organisms are unlikely to perform complex behaviors spontaneously. Instead, shaping breaks down the desired behavior into small, manageable steps.
The steps involved in shaping begin with reinforcing any response that resembles the desired behavior. For example, parents might praise a child for picking up one toy. As...
The steps involved in shaping begin with reinforcing any response that resembles the desired behavior. For example, parents might praise a child for picking up one toy. As...
987
01:20Stream Function
2.1K
In two-dimensional incompressible fluid flow, the continuity equation is essential for ensuring mass conservation, meaning that any change in fluid entering or exiting a region is balanced by a corresponding change elsewhere. For incompressible flow, where density remains constant, this requirement simplifies to the condition that the divergence of the velocity field must be zero. Mathematically, this is expressed as,
2.1K
01:20Capillary Beds
6.7K
Capillary beds are networks of tiny blood vessels that play a crucial role in the circulatory system. These beds are where the exchange of gases, nutrients, and waste products occurs between the blood and surrounding tissues. Each capillary bed consists of numerous capillaries, which are the smallest blood vessels in the body, typically only one cell-thick. This thinness allows for the efficient diffusion of substances.
Capillaries connect arterioles, small branches of arteries, to venules,...
Capillaries connect arterioles, small branches of arteries, to venules,...
6.7K
03:05Acid Strength and Molecular Structure
32.9K
Binary Acids and Bases
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
32.9K
01:20Strength of Cement
482
Strength tests for cement are not performed directly on neat cement paste due to difficulty in obtaining consistent, reliable specimens. Instead, cement is typically tested in the form of cement-sand mortar.
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...
For compressive strength tests, ASTM C 109-05 standards prescribe a cement-sand mix ratio of 1:2.75 and a water/cement ratio of 0.485 for making 2-inch cubes. These cubes are mixed, cast, and cured in saturated lime water at 23°C until testing. Flexural strength testing, outlined in...
482
03:37Molecular Shape and Polarity
74.9K
Dipole Moment of a Molecule
74.9K