Structural geology and tectonics of the Orville Coast region, southern Antarctic Peninsula, Antarctica

Journal Article · Sun Jan 01 04:00:00 EST 1989 · United States Geological Survey, Professional Paper; (USA)

OSTI ID:6225337

Kellogg, K S; Rowley, P D

The oldest rocks in the Orville Coast of the southern Antarctic Peninsula and in adjacent parts of eastern Ellsworth Land belong to a Middle and Late Jurassic calc-alkalic magmatic arc that developed along the axial part of the peninsula. The main exposed product of the magmatism, which developed in response to eastward subduction beneath the Pacific margin of the peninsula, is mostly andesitic to dacitic volcanic rocks of the Mount Poster Formation. The Latady and Mount Poster Formations were strongly folded during Late Jurassic and (or) Early Cretaceous time during the Palmer Land deformational event. Fold axes are parallel to the prominent bend or orocline in the southern Antarctic Peninsula, and vergence is to the south or southeast. Thrust faults with apparently small displacement dip to the north or northwest in the Hauberg and Wilkins Mountains. Renewed arc magmatism, resulting in emplacement of gabbroic to granitic plutons of the Lassiter Coast Intrusive Suite, began before 115 Ma, sometime after folding ceased, and continued for at least 15 m.y. Dikes of similar composition to the plutonic rocks and anastomosing, randomly oriented, hydrothermal quartz veins were intruded during late stages of plutonism; copper mineralization associated with the late hydrothermal activity took place in the Sky-Hi Nunataks and Merrick Mountains. Small-displacement, predominantly right-lateral strike-slip faults, oriented about N. 70{degree}W., are probably satellitic to the right-lateral Ellsworth fault system. Drag along the Ellsworth fault system may account for clockwise-rotated paleomagnetic directions from Lower Cretaceous intrusive rocks in the Sweeney and Hauberg Mountains of the Orville Coast. The southern peninsula underwent deep erosion and peneplantation in the Late Cretaceous and early Tertiary, followed by gradual arching and rifting.

• OSTI ID: 6225337
• Journal Information: United States Geological Survey, Professional Paper; (USA), Journal Name: United States Geological Survey, Professional Paper; (USA) Vol. 1498; ISSN XGPPA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AGE ESTIMATION
ANTARCTIC REGIONS
ANTARCTICA
AUSTRALASIA
CENOZOIC ERA
CHALCOGENIDES
COASTAL REGIONS
COPPER ORES
CRETACEOUS PERIOD
DEFORMATION
DIKES
DRAG
EROSION
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
HYDROTHERMAL ALTERATION
ICE
IGNEOUS ROCKS
JURASSIC PERIOD
MAGMATISM
MAGNETISM
MESOZOIC ERA
MINERALIZATION
MINERALS
MOTION
MOUNTAINS
NEW ZEALAND
ORES
ORIGIN
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PACIFIC OCEAN
PALEOMAGNETISM
PLUTONIC ROCKS
POLAR REGIONS
QUARTZ
ROCKS
ROTATION
SEAS
SILICON COMPOUNDS
SILICON OXIDES
SUBDUCTION ZONES
SURFACE WATERS
TECTONICS
TERTIARY PERIOD
VOLCANIC ROCKS