to get there
- Field program (Neves area): August 22nd
- Lecture program (Varna, Brixen): August 25th
- 22nd afternoon (16.00):
arrival at Bruneck (Brunico) train station and transfer to the
Chemnitzerhütte (Rifugio Porro) for dinner and overnight
- 23-24th : field work on the
glaciated outcrops in front of the southern Grosser Möseler
(Mesule) glacier (photo)
- 25th morning: move to Varna
- 25-28th: classroom
teaching in Varna (Brixen)
- 29th morning: depart
The field course
will be held in the Nevessee
Neves) area (South Tyrol, northeast Italy) and will address the
structural analysis of deformation structures within the Tauern
meta-granitoids. The structures are present on polished outcrops at
the base of the south-eastern Grosser
that provide spectacular
exposures for structural analysis of 2D deformation geometries. The
area is located at about 2600 m and is reachable by a well-marked
track from the Chemnitzerhütte
(Rifugio Porro), at 2419 m.
We will stay at this hut, which one reaches along a broad path from
the Nevessee in about 1 hr 45 mins walking time (about a 500 m
>From the geological point of view, the area is located
just north of a thick belt of Alpine amphibolite facies mylonites
(well visible on the aerial photograph of Fig.
which can be
investigated along the path from the hut to the glacier. The study
area represents a low strain domain, which largely escaped the Alpine
structural overprint. It is therefore possible to analyse in detail
the progressive development of discrete ductile shear zones that
exploit a network of brittle precursors (joints) and pre-existing
magmatic or fluid–induced compositional heterogeneities.
the field analysis, students will gain familiarity with the following
magmatic structures (including different acid
and basic intrusives, magma mingling, etc.): Fig.
epidote veins and alteration haloes along
joints and fractures (Fig.
single and paired discrete shear zones
nucleating on planar compositional and structural heterogeneities
6d, Fig.6e , Fig.6f, Fig.6g);
veins (Fig. 7a,
intersecting ductile shear zones
late stage quartz-chlorite-epidote vein systems
Fig. 9b, Fig. 9c).
all the pictures !!!
N.S. and Pennacchioni, G., 2005. The
control of precursor brittle fracture and fluid–rock
the development of single and paired ductile shear zones. Journal
of Structural Geology
27, 645–661. PDF
N.S. and Pennacchioni, G., 2010. Why
calcite can be stronger than quartz. Journal
of Geophysical Research
B01402, doi:10.1029/2009JB006526. PDF
- Pennacchioni, G. and
Mancktelow, N.S., 2007. Nucleation
and initial growth of a shear zone network within compositionally and
structurally heterogeneous granitoids under amphibolite facies
29, 1757-1780. PDF
will be taught to analyse:
the time relationships between the different
intrusions of the pre-Alpine protolith;
control of structural and compositional heterogeneities on nucleation
of shear zones;
role of fluids during ductile deformation;
kinematic relationships between the different structural element of the
deformation network (shear zones and veins);
interference between intersecting shear zones.
The second part of the school will include a series of lectures The classes will cover the following topics:
1) Solid-state ductile deformations within cooling of plutons.
Teacher: Giorgio Pennacchioni
(Padua University, Italy)
The lecture will describe the solid-state
deformation structures developed in different plutons (e.g.: Adamello, Southern
Alps, Italy; Mono Pass Intrusive Suite, Sierra Nevada, California) during their
cooling. The main focus will be on deformation structures developed at
high temperatures (T ≥ 500°C) and the role of structural (joints) and
compositional (e.g. dykes) heterogeneities on nucleation of shear zones. The
deformation structures in cooling plutons will be compared with those
seen during the field excursion in the Tauern metagranitoids in the Neves area.
These observations provide the basis of a new model for the nucleation of
ductile shear zones in granitoid plutons.
rock interaction along shear zone networks.
Teacher: Stephen Cox
involvement in the mechanics of faults and shear zones:
- failure modes
Mohr circle treatments of brittle fracture mechanics
- evidence for overpressures during rock deformation
- failure mode diagrams - a new way to explore the effects of fluid pressures on rock stress
(b) Coupling between
deformation and permeablity enhancement in faults and shear zones.
fluid-rock interaction in faults and shear zones: reaction weakening
and reaction strengthening.
signatures of reactive transport in networks of faults and shear
Practical exercises - application of failure mode diagrams to explore the strength and mechanical behaviour of rocks.
3) Microstructural studies on fluid-rock interaction and deformation mechanisms in mylonitic shear zones.
Teacher: Luca Menegon (Tromsø University, Norway)
will show examples of deformation microstructures of quartz and
K-feldspar in natural shear zones formed at mid- to lower-crustal
conditions. The observations will be discussed in terms of (i) the
effect of fluid rock interaction on the activation of different
deformation mechanisms, and (ii) the implications for the strength
evolution of the mid- to lower crust. The following topics will be
(a) Introduction to methods
for quantitative microstructural and texture analysis (e.g., SEM-based
techniques, image analysis, texture goniometry)
(b) Effect of hydrous fluids
on the creep strength and deformation microstructures of quartz: when
can we extrapolate lab-derived flow laws to natural conditions?
(c) Fluids, replacement reactions and deformation in granitoids
(d) Transition from fracturing to viscous flow in K-feldspar
analogue and numerical
modelling of shear
Teachers: Neil Mancktelow (ETH-Zurich, Switzerland)
and Dani Schmid (Oslo University, Norway)
localization and the development of heterogeneous shear zones
zone ends and transfer zones
(c) Stress refraction in layered and
variation in pressure in deforming rocks and its importance for
controlling fluid-rock interaction
structures developed around planar heterogeneities in shear zones
and rotation and/or stabilization of clasts in shear zones
5) Deformation of Quartz in Nature and Experiments.
Teachers: Michael Stipp (GEOMAR Kiel,
(a) Crystal plastic deformation microstructures in nature and experiments
(b) The brittle to plastic transition in nature and experiments.
(c) Experimental piezometers and flow laws: Correlating
deformation conditions between laboratory and
(d) Rheology of the Earth's crust.
Practical exercises -Measuring stress in nature and experiment
6) Experimental and microstructural investigations of rocks deforming at varying stresses.
Teacher: Claudia Trepmann (Ludwig-Maimilians University Munich, Germany)
The lecture will show examples, how microstructures can be used to give
information on the stress history during deformation. For this, TEM, SEM
and EBSD analyses of naturally and experimentally produced
microstructures will be discussed in the view of the following topics:
(a) Deformation at the lower tip of a seismic active fault zone
- Deformation at transiently high and then rapidly decreasing stresses
- Recrystallization after deformation at low stress
(b) Deformation of HP-LT metamorphic rocks in subduction zones
- Low stress deformation by dissolution-precipitation creep
- Local stress concentrations due to viscosity contrasts
area is easy of access and no climbing or special Alpine experience is
required. However, the field course is in a high mountain environment
and adequate equipment is essential. What
do you need? Download the checklist!
The work area is at 2600m a.s.l. We will be
outside the whole day (with a packed lunch provided by the hut). The
weather can be warm and sunny but can also be very cold, windy and, in
the worst case, snowy.
participants: priority is given to PhD
students, post-Docs and young researchers specializing in structural
geology. Finishing masters students in the process of starting PhD will
be considered if there are places left.
Course max number of participants: 35 (on a
first come first served basis).