ABSTRACT
Three geological maps in scale of 1:250,000 along the INDEPTH 3
survey line were made according to our field investigations in
1998 and 1999, extrapolated using TM image interpretation,
combined with results from other previous work. This dissertation
summarizes relevant geological information with references,
including stratigraphy and fossil ages mainly from Chinese
literature and discusses structure and shortening amount and the
constraints on the ages. The Baingoin sheet of the geological map
covers an area from N31 to N32;30', from E88;30' to E90;30'. The
detailed structural and stratigraphic cross sections indicate
about 50% shortening of the early-mid Jurassic, about 30%
shortening of the early Cretaceous, about 15-20% shortening of the
late Cretaceous and Paleogene, and only gentle tilting or no
disturbance of Neogene in most places. The Shuanghe sheet of the
geological map covers an area from N32;30' to N34;00', from
E87;30' to E89;30'. The detailed structural and stratigraphic
cross sections show that the strata of Jurassic and Triassic age
are moderately to strongly folded throughout this region and cut
in places by thrusts, with N-S shortening amounts up to about 50%.
Deformation of late Cretaceous and Paleogene strata varies from
one place to another. Generally, they are also folded, and cut in
places by thrusts. A N-S shortening amount of about 15%-20% is
very roughly estimated. The Dogai Coring sheet of the geological
map covers an area from N34 to N35;30', from E88 to E90. Further
work is needed to constrain the shortening deformation of the
Tertiary red beds across the area. The first detailed geological
map (Scale: 1:100,000) in the northeastern Nyainqentanglha region
and two structural and stratigraphic cross sections are presented
based on our field observations. Three fault systems have been
recognized: (1) sinistral strike-slip ductile shear zone within
the low-grade metamorphic rocks; (2) reverse faulting, along which
the low-grade metamorphic rocks are thrust over the red clastics,
and which appears to cut the unconformity; (3) sinistral
strike-slip fault along the south front of the range, which cuts
both of the above-mentioned faults.
Li, Y., 2004. Geological mapping and crustal shortening of
central Tibet. Unpublished PhD dissertation, State University of
New York at Albany. 157 pp., +xi; 8 folded maps.
University at Albany Science Library call number: SCIENCE
MIC Film QE 40 Z899 2004 L5
Copies of this PhD dissertation can be ordered
from Proquest UMI
Front matter (title,
table of contents, abstract, acknowledgements) - 0.15MB pdf
file
Figure pages in dissertation
(colour
and greyscale photos and figures, with captions): - 22.7MB
pdf file
Plate 1 - Indepth
III project route and seismometer locations (on TM and MSS
image base, scale ~1:710,000)
(false-colour image mosaic
with map overlay annotations) - 10.4MB pdf file
Plate 2 - Geological
map of the northeastern Nyainqentanglha, Tibet
(coloured geological map;
scale ~1:86,000) - 0.1MB pdf file
Plate 3 - Landsat
TM image of the Baingoin region, central Tibet
(false-colour TM satellite
image; scale ~1:278,000) - 5.7MB pdf file
Plate 4 - Geological
map of the Baingoin region, central Tibet
(coloured geological map;
scale ~1:278,000) - 2.4MB pdf file
Plate 5 - Landsat
TM image of the Shuanghe region, north-central Tibet
(false-colour TM satellite
image; scale ~1:275,000) - 6.4MB pdf file
Plate 6 - Geological
map of the Shuanghe region, north-central Tibet
(coloured geological map;
scale 1:~275,000) - 2.1MB pdf file
Plate 7 - Landsat
TM image of the Dogai Coring region, north-central Tibet
(false-colour TM satellite
image; scale ~1:285,000) - 6.4MB pdf file
Plate 8 - Geological
map of the Dogai Coring region, north-central Tibet
(coloured geological map;
scale ~1:277,000) - 1.7MB pdf file