[meteorite-list] Slickensides

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:49:03 2004
Message-ID: <3BB0B9C8.C553E6EB_at_lehrer1.rz.uni-karlsruhe.de>

Hello All!

I just found several interesting sites on the slickenside topic:

01) Structural Implications of Slickensides and the Juneau Icefield,
    Juneau, AK and Atlin, B.C.

A.J. ROMEO, Univ. of Florida, Dept. of Geology, Gainesville, 32611,
and Foundation for Glacier and Environmental Research, Pacific Science
Center, Seattle, WA 98019.

Slickensides of the Juneau Icefield record rapid early to mid-Tertiary
uplift of the Coast Range batholith. Orientations of 225 slickensides
reflect a regionally extensive set of ductile shear and brittle faults
extending ~60 km southwest to northeast through the study area north
of Juneau, Alaska. This shear zone contains near vertical eastward
dipping slickensides with horizontal slickenlines recording right- and
left-lateral strike-slip motion. This shear zone, informally named the
Seratine shear zone, is in the northern extremities of the Coast shear
zone and evolved from thrusting along the Coast Range Megalineament
zone during rapid early-Tertiary uplift. No significant measurement
of displacement was recorded in the Eocene granite and granodiorite
plutons.

This animation shows the faulting process. The different fill patterns
represent horizontal rock units. Can you see how one rock mass moves
past another as they are faulted? It is along this fault line that the
slickensides occur.

Go to: http://www.coolrox.com/abstract.htm

02) Slickensides are polished, grooved surfaces that occur along shear
planes within the soil. These shear planes result from the shrink-swell
action of smectite clays that accompanies cycles of wetting and drying.
As Vertisols are wetted, the soil volume increases; the volume then
decreases as the soils dries. Slickensides form along the internal shear
planes as soil aggregates move past one another in response to these
volume changes.

http://soils.ag.uidaho.edu/soilorders/vertisol/7.htm

03) The Vuache fault is exposed at the foot of Mandalaz peak in
Haute-Savoie, France, displaying a remarkably large slickenside
or "fault mirror." This fault was responsible for the magnitude-5.3
Epagny-Annecy earthquake of 15 July 1996. When the rocks along
a fault rub against each other, their surfaces become smoothed,
lineated, and grooved. This may involve simple friction, or if
the fault surface was once deeply buried, actual mineral growth
may respond to the forces on the fault.

http://geology.about.com/library/bl/images/blslick.htm


Best wishes,

Bernd
Received on Tue 25 Sep 2001 01:07:20 PM PDT