ABSTRACT
This study deals with the tectonic evolution of Tethys during the
Mesozoic. A critical question concerning Tethyan geology is how
far the Tethys ocean extended westwards in the Mediterranean
region. Because this question can only be answered by studying in
detail the opening history of the Alpine ocean, a critical area
involving Triassic and Jurassic sediments was mapped in the Albula
Pass area in eastern Switzerland. The mapping shows that the main
rifting in the Alps took place during the Lias with a very weak
extensional event during the medial Triassic. The record of these
events is now found in the Lower and Middle Austroalpine units,
which deformed through a complex sequence of events involving a
hitherto unknown early south-vergent folding of the Middle
Austroalpine Aela Nappe. The stratigraphic analysis undertaken
during this study demands that the Aela Nappe be placed farther
north than hitherto believed, near the Lower Austroalpine facies
realm, mainly because of the demonstration that the typically
Lower Austroalpine Alv Breccia also occurs in the Aela Nappe. In
order to place the Jurassic and the Triassic rifting events into
their appropriate tectonic settings, a regional tectonic synthesis
of the Mediterranean Alpides was undertaken. This synthesis shows
that the Triassic and Jurassic rifting events in the Alps was
related to the opening of Neo-Tethys and to the opening of the
Atlantic ocean respectively. Because only Jurassic rifting
eventually led to generation of ocean-floor, the Alpine ocean and
the Mesozoic-Cainozoic oceans west of it formed as parts of the
Atlantic Ocean and are tectonically unrelated to Tethys. The two
oceanic systems merged in the western Carpathians. Neo-Tethyan
opening, which controlled the Triassic rifting events in the Alps
was controlled and was largely coeval with the closing of the
Palaeo-Tethys, described in detail for the first time in this
dissertation. The closure of Palaeo-Tethys generated an orogenic
belt, extending from the Carpathians to the Pacific Ocean. It is
herein named the Cimmerides and follows closely the later Alpides,
products of Neo-Tethys, throughout southern Eurasia. This spatial
association resulted in complex overprinting of the Cimmerides by
the Alpides, which hindered the recognition of the former for
nearly a century. The Cimmeride orogenic system was completed by
the latest Jurassic with some late events during the early
Cretaceous along the Great Khingan-Shitka suture in the Far East.
An important result of this study is the recognition of the
dominating effect of the Palaeo-Tethys on the tectonic evolution
of the Mediterranean Alpides until the latest Triassic.
Sengor, A.M.C., 1982. The geology of the Albula Pass area,
eastern Switzerland in its Tethyan setting: Palaeo-Tethyan factor
in Neo-Tethyan opening.
Unpublished PhD dissertation, State University of New York at
Albany. 405pp., +xviii; 8 folded plates (maps)
University at Albany Science Library call number: SCIENCE
MIC Film QE 40 Z899 1982 S46
Copies of this PhD dissertation can be ordered
from Proquest UMI
Front matter (title,
table of contents, abstract, acknowledgements) - 0.4MB pdf
file
Photo pages in dissertation
(colour
and greyscale photos with captions): - 7.4MB pdf file
Plate 1 - Geological
Map
of
the Albula Pass Area (Switzerland)
uncoloured geological map, scale 1:10,000 - 2.3MB pdf file
Plate 6 - Outcrop
and
Index
Map
of the Albula Pass Area
uncoloured outcrop and index map, scale 1:10,000 - 0.6 MB pdf file
Plate 3 - Tectonic
Map
of
the
Albula Pass Area
uncoloured tectonic map, scale 1:10,000 - 0.8 MB pdf file
Plate 4 - Geological
Cross-Sections
of
the
Albula Pass Area
uncoloured geological cross-sections, 1:10,000, vert. ex. 2x - 1.1
MB pdf file
Plate 2 - Stratigraphic Synopsis of the Albula Pass Area
uncoloured stratigraphic chart (scale 1:2500) - 0.6 MB pdf file
Plate 5 - Stratigraphy of the base of the Aela Nappe in the
Albula Pass
uncoloured
stratigraphic
chart (scale 1:100) - 0.6 MB
pdf file
Plate 7 - Main
tectono-stratigraphic units of the Circum-Mediterranean Alpides
uncoloured geological chart
- 3.3MB pdf file
Plate 8 - Late
Triassic to Early Cretaceous schematic stratigraphic synopsis of
the Circum-Mediterranean Alpides
uncoloured stratigraphic
chart - 2.9MB pdf file
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