عنوان

Tectonic evolution of the NW-Himalayan thrust front:

Number

TLpq304305614

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Tectonic evolution of the NW-Himalayan thrust front:

General Material Designation

[Thesis]

First Statement of Responsibility

P. M. Blisniuk

Title Proper by Another Author

The Trans-Indus Ranges, northern Pakistan

Subsequent Statement of Responsibility

L. J. Sonder

Name of Publisher, Distributor, etc.

Dartmouth College

Date of Publication, Distribution, etc.

1996

Specific Material Designation and Extent of Item

193

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

Dartmouth College

Text preceding or following the note

1996

Text of Note

The results of structural, stratigraphic and paleomagnetic work in the Trans-Indus Ranges of northern Pakistan are presented. The Trans-Indus Ranges form the western part of the NW-Himalayan frontal thrust system, which comprises structural re-entrants and promontories with wave-lengths between 50 and 150 km. The structure of the Trans-Indus Ranges is characterized by abrupt lateral variations in tectonic style, between mainly compressive deformation along the central parts of re-entrants and promontories, and transpressive deformation along their lateral flanks. This complex geometry of the thrust front seems to be largely controlled by a system of frontal and lateral structural ramps, formed by north-dipping flexures and normal faults offsetting the basement. Balanced cross-sections, based on the integration of stratigraphic and structural mapping with seismic reflection data and well logs, show that the amount of convergence along the Trans-Indus Ranges is on the order of 10 km. The history of deformation along the Trans-Indus Ranges is constrained by sedimentological and magnetostratigraphic studies of synorogenic foreland basin deposits, which contain evidence for two main phases of tectonic activity. Locally derived conglomerates in usd \simusd3.5-4 Ma old deposits are interpreted as evidence for Early Pliocene extension along north-dipping flexures and normal faults on the northern flank of a peripheral bulge south of the NW-Himalayan foreland basin. Locally derived conglomerates in usd\leusd1.2 Ma deposits are related to the ongoing convergence along the Trans-Indus Ranges, during which normal faults and flexures formed during the earlier extension were used as thrust ramps. The rate of shortening along the frontal thrust system in the Trans-Indus thus is usd\geusd8 mm/a, similar to shortening rates previously reported in the Salt Range in the eastern part of the frontal thrust system.

Earth sciences

Geology

Geophysics

L. J. Sonder

P. M. Blisniuk

Electronic name

p

[Thesis]

276903

a

Y