What is isostatic compensation?
Definition of isostatic compensation : the deficiency of mass in the earth’s crust below sea level that exactly balances the mass above sea level.
How do you calculate isostatic equilibrium?
In isostatic equilibrium, the pressure at the bottom of each column (below where there are any differences in the density) is the same in both columns (P1=P2. Write out the sum for the pressure in each column (this reduces to the sum of the density times the thickness in each layer) Set the pressures equal.
What are isostatic adjustments?
Isostatic adjustment refers to the transient (102−104 years) or long term (> 105 years) nonelastic response of the earth’s lithosphere to loading and unloading due to erosion, deposition, water loading, desiccation, ice accumulation, and deglaciation.
How do you know if something is isostatically compensated?
Accordingly, a topographic feature is said to be isostatically compensated when the deficiency of mass buried below the topography exactly equals its excess mass. The compensation depth is the shallowest depth below which the stress state induced by the topography and its compensation is hydrostatic.
What isostatic means?
adjective. Geology. Characterized by or involving the equilibrium that exists between parts of the earth’s crust. ‘isostatic depression of the earth’s crust’
What is an isostatic?
Noun. isostatic (plural isostatics) A line of constant stress. A state of equilibrium between two forces.
What is depth of compensation in geology?
In the theory of isostasy, a mass above sea level is supported below sea level, and there is thus a certain depth at which the total weight per unit area is equal all around the Earth; this is known as the depth of compensation.
What is depth of compensation?
Definition of depth of compensation : the depth below the earth’s surface at which the topographic inequalities are compensated by variations in rock density so that all columns of rock or of rock and water above the depth have approximately equal weights.
How does isostatic adjustment?
Though the ice melted long ago, the land once under and around the ice is still rising and falling in reaction to its ice-age burden. This ongoing movement of land is called glacial isostatic adjustment. Earth is always on the move, constantly, if slowly, changing.
What causes isostatic adjustment?
Isostasy is the great equalizer. If weight is added to the Earth’s crust, the crust sinks. If weight is removed, the crust rises. Tectonic stress and climate are both capable of redistributing weight and, therefore, both cause isostatic changes.
What is airy isostasy?
In isostasy. The Airy hypothesis says that Earth’s crust is a more rigid shell floating on a more liquid substratum of greater density. Sir George Biddell Airy, an English mathematician and astronomer, assumed that the crust has a uniform density throughout.
How does isostatic press work?
HIP, Hot Isostatic Pressing, is one of material processing methods, which compresses materials by applying high temperature of several hundreds to 2000 °C and isostatic pressure of several tens to 200MPa at the same time. Argon is the most commonly used pressure medium. Hot pressing is very similar to HIP.
What is the relationship between necking depth and isostatic response?
If the necking depth is deeper than the isostatic compensation depth, then uplift can occur (Fig. 22.4B), while if it is shallower, then subsidence occurs (Fig. 22.4C). The mass redistribution due to what is referred to as the intrinsic necking needs to be considered before determining the isostatic response to changes in lithospheric density.
How does isostasy affect the landscape?
Isostasy affects landscape in much the same way as tectonic stress. That is, through uplift and subsidence. Because of this, it is sometimes difficult to separate uplift/subsidence brought on by isostatic changes from those brought on directly by tectonic activity. This problem is addressed in Chapter 7.
Is isostasy a secondary forcing agent?
Climate activates erosion and deposition and can cause glaciation. Given its dependence on climate and tectonic stress, we will consider isostasy to be a secondary forcing agent. Sea level change can also redistribute weight and thus also cause isostatic changes.
How does tectonic stress cause isostatic changes?
If weight is added to the Earth’s crust, the crust sinks. If weight is removed, the crust rises. Tectonic stress and climate are both capable of redistributing weight and, therefore, both cause isostatic changes. Tectonic stress can displace rock and change the temperature of rock (and therefore its density).