Geology Reference
In-Depth Information
sub-spherical geometry, and the corresponding
fraction 1 -
f
of plate-like particles.
He found that the two inclinations were related
by the following simple equation:
References
Arason P, Levi S (1990) Models of inclination shal-
lowing during sediment compaction. J Geophys Res
95(B4):4481-4499
Bartels J (1936) The eccentric dipole approximating
the earth's magnetic field. Terr Magn Atmos Electr
41:225-250
Besse J, Courtillot V (1988) Paleogeographic maps of the
continents bordering the Indian Ocean since the early
Jurassic. J Geophys Res 93(B10):11,791-11,808
Besse J, Courtillot V (1991) Revised and synthetic ap-
parent polar wander paths of the African, Eurasian,
North American and Indian plates, and true po-
lar wander since 200 Ma. J Geophys Res 96(B3):
4029-4050
Besse J, Courtillot V (2002) Apparent and true polar
wander and the geometry of the geomagnetic field over
the last 200 Myr. J Geophys Res 107(B11):2300
Butler RF (1992) Paleomagnetism: magnetic domains to
Geologic Terranes. Blackwell Scientific Publications,
Boston, 238 pp
Cande SC, Stegman DR (2011) Indian and African plate
motions driven by the push force of the Réunion plume
head. Nature 475:47-52. doi:
10.1038/nature10174
Cande SC, LaBrecque JL, Haxby WF (1988) Plate kine-
matics of the South Atlantic: chron C34 to present.
J Geophys Res 93(B11):13479-13492
Chase CG (1979) Asthenospheric counterflow: a kine-
matic model. Geophys J R Astron Soc 56:l-18
Coupland DH, Van der Voo R (1980) Long-term
nondipole components in the geomagnetic field during
the last 130 m.y. J Geophys Res 85(B7):3529-3548
Dewey JF, Cande S, Pitman WC (1989) Tectonic evolution
of the India/Eurasia collision zone. Eclogae Geol Helv
82(3):717-734
Domeier M, Van der Voo R, Torsvik TH (2012) Pale-
omagnetism and Pangea: the road to reconciliation.
Tectonophysics 514:14-43
Duncan RA (1984) Age progressive volcanism in the New
England seamounts and the opening of the central
Atlantic Ocean. J Geophys Res 89(B12):9980-9990
Dunlop DJ, Özdemir Ö (1997) Rock Magnetism.
Cambridge University Press, Cambridge, 573 pp
Eubank RL (1999) Nonparametric regression and spline
smoothing. Marcel Dekker, New York, 337 pp
Evans DA (2003) True polar wander and supercontinents.
Tectonophysics 362(1):303-320
Fisher RA (1953) Dispersion on a sphere. Proc R Soc
London A217:295-305
Frankel HR (2012) The continental drift controversy:
Wegener and the early debate. Cambridge University
Press, Cambridge, 632 pp
Gilder S, Chen Y, Cogné JP, Tan X, Courtillot V, Sun D, Li
Y (2003) Paleomagnetism of Upper Jurassic to Lower
Cretaceous volcanic and sedimentary rocks from the
tan I
D
f tan I
F
(6.73)
The empirical parameter
f
is called
flattening
factor
. In more recent times, Tauxe and Kent
(
1984
) have confirmed the validity of this equa-
tion and showed that
f
Š
0.55 for sediments with
detrital hematite. This value indicated that the
observed shallower inclinations could be associ-
ated with inclination errors rather than with non-
dipole components of the paleomagnetic field
(e.g., Gilder et al.
2003
). The present orienta-
tion of paleomagnetists regarding the origin of
the inclination anomaly is that it is associated
with sedimentary inclination errors and/or poor-
quality data, while a solution to the Pangaea fit
can be found by selecting reliable data, correcting
inclination errors, and improving the plate recon-
structions (e.g., Domeier et al.
2012
).
Problems
1. Interpreting the APW path of a continent as
the trajectory of a moving point at the Earth's
surface, explain what kind of information can
be obtained about the kinematics at a reference
site
S
;
2. Assuming that a tectonic plate is rotating
clockwise about an Euler pole located at
(0
ı
N,90
ı
E) with angular velocity ¨
D
1
ı
/Myr,
determine the northward and eastward
components of velocity for a reference point
at (30
ı
N,45
ı
E), and the rate of variation of its
inclination and declination;
3. Given a mean paleopole for India at 100 Ma,
describe a method to fit India to Madagascar
in three steps;
4. Find an expression/algorithm for calculating
the predicted paleolatitude and declination at a
point
P
given the paleolatitude and declination
at a reference site
S
.
