[Geoqus] Mantle viscosity at EGU 2012

[Holger Steffen]

(with apologies for multiple postings)

Dear colleagues,

We would like to announce our mantle viscosity and glacial isostatic
 adjustment session at EGU2012 and encourage you to submit an abstract:

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
GD3.4/G3.3/TS1.7
Mantle viscosity and the post-glacial uplift

EGU General Assembly in Vienna: 22 to 27 April 2012
Deadline for abstract submission: 17 January 2012, 24:00 CET
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We are pleased to announce our invited presenter Larry Cathles!

More information on our session can be found below and on:
http://meetingorganizer.copernicus.org/EGU2012/session/9634

We look forward to discussing mantle viscosity with you!

Willy and Holger

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GD3.4/G3.3/TS1.7
Mantle viscosity and the post-glacial uplift
Conveners: Willy Fjeldskaar and Holger Steffen

Scientific investigations of the glacial isostatic adjustment (GIA)
 started in the early 18th century in Fennoscandia, and since then various
 data have been collected, e.g. relative sea-level (RSL), tide gauges
 records, leveling, GPS, absolute and relative gravity measurements, and
 nowadays also data from satellite missions. With the help of these data
 investigations regarding the mantle structure have been made in
Fennoscandia, North America and a few other regions in the world.

However, there are still remarkable differences in the resolved
properties
of the mantle, especially in Fennoscandia. Early results, for example,
 include a 100 km thick low viscosity asthenosphere with 1.3×10**19 Pa s
 (van Bemmelen and Berlage, 1935), a 200 km thick asthenosphere with 10**20
Pa s (McConnell, 1968), a 75 km thick asthenosphere with 4 × 10**19 Pa s
 (Cathles, 1975), and a 100 km thick asthenosphere with 1.2×10**19 Pa s
 (Wolf, 1987). GIA modeling has undergone a huge improvement since its
 beginning. Nowadays with the computational power, 3D spherical models
 based on different techniques are mainly in use. They include the
 theoretical basics such as sea-level equation, earth rotation and,
partly, self gravitation.

Appropriate regional models also exist, which may allow the inclusion of
 crustal structures such as sedimentary basins and faults for selected
 special investigations such as post-glacial-induced earthquakes. The Earth
structure beneath Fennoscandia seems now to be generally characterized by
 a laterally varying lithosphere with a thick root of more than 200 km in
 central-east Fennoscandia, then becoming thinner to the outer parts.
 South-west Sweden is expected to have about 100 km, the German North Sea
 coast as well as the Norwegian Atlantic coast about 80 km. A
low-viscosity
asthenosphere underneath the elastic lithosphere is still under debate.
 The upper-mantle viscosity can be bracketed between 10**20 and 10**21 Pa
 s, whereas the latest results calculated from different data yield between
(3–8)×10**20 Pa s. The viscosity is getting higher towards the lower
 mantle.

In this session we invite papers, which are focused on determination of
 the mantle viscosity from post-glacial rebound and its importance and
 impact on GIA phenoma around the world.























._____________________________________.
|                                     |
| Dr. Holger Steffen                  |
| Department of Geoscience            |
| University of Calgary               |
| 2500 University Drive NW            |
| Calgary, AB, T2N 1N4                |
| Canada                              |
|                                     |
| Office: MS214                       |
| Phone:  +1 403 210 6476             |
| Fax:    +1 403 284 0074             |
| Email:  sholger at ucalgary.ca         |
| Web:    http://www.ucalgary/steffen |
|_____________________________________|