ABSTRACT
The Lewis Hills is the southernmost of the four Bay of Islands
Ophiolite Complex massifs. These massifs are considered to be the
dissected remnants of a once nearly continuous thrust slice of
oceanic crust and upper mantle of Early Ordovician age. The Lewis
Hills Massif may be divided into three north south trending zones.
The eastern zone (Bay of Islands Complex) is composed of variably
deformed and recrystallized gabbro, troctolite, wehrlite and
dunite cumulates and harzburgite tectonites. The western zone
(Little Port Assemblage) consists of greenschist facies
metagabbros, diabase dikes and minor quartz-diorite bodies. The
central zone (Mount Barren Assemblage) is a 3 kilometer wide zone
of highly deformed metagabbros and amphibolites cut by syn- and
post- kinematic mafic and ultramafic intrusive bodies. The central
zone grades into the western zone but has a sharp igneous contact
against the eastern zone, it is proposed that the central zone
rocks represent the deep crustal levels of an oceanic fracture
zone preserved between two less deformed assemblages of oceanic
crust and upper mantle. Along strike to the northeast, rocks
similar to those of the eastern and western zones of the Lewis
Hills are exposed in the Bay of Islands Ophiolite Complex and the
Coastal Complex respectively. The Mount Barren Assemblage has not
been previously described as part of the Coastal Complex and
provides an important link between the Bay of Islands and Coastal
Complexes. Detailed studies in the Lewis Hills permit fairly well
constrained models to be constructed for the kinematics and timing
of processes during the evolution of oceanic fracture zones and
the obduction of the Bay of Islands Complex.
Karson, J.A., 1977. Geology of the northern Lewis Hills, western
Newfoundland.
Unpublished PhD dissertation, State University of New York at
Albany. 474pp., +xxii; 5 folded plates (maps)
University at Albany Science Library call number: SCIENCE
MIC Film QE 199 K37X
Copies of this PhD dissertation can be ordered
from Proquest UMI
Front matter (title,
table of contents, abstract, acknowledgements) - 1.1MB pdf
file
Photo pages in dissertation
(colour
and greyscale photos with captions): - 32.6MB pdf file
Plate 1a - Geology
of the northern Lewis Hills, western Newfoundland (coloured
geological outcrop map, scale ~1:14,800) 26.2MB pdf file
Plate 1b - Geology
of the southern Lewis Hills, western Newfoundland (coloured
geological outcrop map, scale ~1:15,840) 14.4MB pdf file
Plate 1x - map
legend from plate 1a 4.4MB pdf file
Plate 2 - Structural
map of shear zones in the northern Lewis Hills, western
Newfoundland (part coloured geological map, scale ~1:14,800)
22.8MB pdf file
Plate 3 - Structural
map of lineations and fold axes in the northern Lewis Hills,
western Newfoundland (uncoloured geological map, scale
~1:14,800) 6MB pdf file
Plate 4 - Structural
cross sections of the northern Lewis Hills, western Newfoundland
(coloured geological sections, scale ~1:14,800) 13.8MB pdf file
Plate 5 - Compressional
velocities of mafic and ultramafic rocks in the northern Lewis
Hills, western Newfoundland
(uncoloured geological map
with overlay diagrams, scale ~1:14,800) 5.7MB pdf file
Table 14 - Relative
chronology of geological events in the northern Lewis Hills
Fig 6.2 - Geological
overview map of the northwestern Lewis Hills
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