Download Crustal Scale Interpretation

Lecture #10:
Lithosphere of Young Mountain Belts
IPRCC and SINOPROBE Short Course:
Lithospheric Evolution through Time
April 8-12, 2011
Walter D. Mooney, Ph.D.
US Geological Survey
Menlo Park, California USA
[email protected]
European Western Alps
Compliled from Tethyan Plate Tectonic Home Page,
At: http://www-sst.unil.ch/Research/plate_tecto/index_main.htm
Area of Research
Tectonic Map of the Western Thetysides
Tectonic Setting
and Crustal Scale
Seismic Lines
Swiss National Science Foundation
research project NRP 20
Nappe
Structures:
Matter Valley
NRP20-W3 Vibroseis line
Interpretation of the NRP20-W3 Seismic Line
based on a Depth Migrated Section
NRP20-W3 seismic line
Crustal Scale Interpretation:
NRP20 Western Traverse
Lithospheric scale interpretation along the
NRP20 Western traverse
Tectonic Setting
and Crustal Scale
Seismic Lines
Swiss National Science Foundation
research project NRP 20
Crustal Scale Interpretation:
ECORS-CROP Traverse
Lithospheric Cross-Section:
ECORS-CROP Traverse
Lithospheric scale interpretation
Location map
Tomographic
cross-section
from
Spakman et
al. (1993)
Interpretation
Gravity Model:
NRP20
Western Traverse
3D Model of the Western Alps
Late Oligocene
Geology, Geophysics and Tectonic Evolution of
the Archean Superior Craton, central Canada
Ron M. Clowes
Earth and Ocean Sciences
University of British Columbia, Vancouver, BC
LITHOPROBE
Superior Province
Line 2: Reprocessed reflection data
Evidence for paleo-subduction zones
20 km
Winnipeg R – Wabigoon terrane
Uchi terrane
50 km
20 km
50 km
Suture 2
2.68 Ga
After White et al., Geology, v. 31, 2003
Moho
Suture 1
White et al., Geology,
v. 31, 2003
2.72 Ga
Figure from van der Velden et al., AGU Monograph, in press
Crustal Scale Interpretation:
ECORS-CROP Traverse
South American Andes
Compiled from: http://www.geo.arizona.edu/geo5xx/geo527/Andes/home.html
Fernando Barra, Robert Fromm, Victor Valencia, Dr. George Zandt
Topography and
Depth to Moho
Iso-depth
curves of
Moho every
25 km
Andes
Terrane map of
South America
Ramos and Aleman (2000)
Schematic Cross Section
of the South American Margin (29º-33ºS)
during Carboniferous to Early Triassic
From Mpodizis and Ramos (1990).
There is erosion of the continental
margin at some subduction zones,
such as western South America.
We can this subduction erosion.
It erodes the continental crust and
returns some of the crust into the
mantle.
Overview: Crustal Growth Models
early extraction of all the crust from the mantle,
long-term growth or
episodic periods of crustal growth?
Source: Bowring,
Samuel and Housh, The
Earth’s Early Evolution,
Science, 269, 1995
Did most of the crust
form by the end of
the Late Archean?
Landward migration of magmatic arc
The Andes – Geophysical Data
Bouguer Anomaly across the Central Andes
Götze et al., 1994
Distribution of
Seismicity
seismicity recorded and
located by NEIC-USGS
between 1990 and 2000
Crustal Thickness
across the Central Andes ( 12-22ºS)
station distribution of the
BANJO/SEDA deployment
(Beck, Zandt)
Swenson et al. (2000)
Average Cross Section
through the Central Andes
India Asia Collision (before)
India - Asia collision (after)
INDEPTH I + II
Royden, Burchfiel, Van der Hilst (Science, 2008)
Subduction of Indian lithosphere beneath Tibet: How far north does it go?
Li et al. (EPSL, 2008)
Subduction of Indian lithosphere beneath Tibet: How far north does it go?
west
Li et al. (EPSL, 2008)
east
Subduction of Indian lithosphere beneath Tibet: How far north does it go?
Li et al. (EPSL, 2008)
Subduction of Indian lithosphere beneath Tibet: How far north does it go?
northeastern plateau not underlain by
Indian lithosphere?
Li et al. (EPSL, 2008)
Li et al. (in preparation)
Li et al. (in preparation)