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Abstract:
This study covered an area on the western side of the Denman Glacier and the Obruchev Hills, where the predominantly granulite-facies metamorphic rocks exposed of rather different composition. They are intruded by a wide variety of plutonic rocks, including a major batholith of syenitic to granitic composition at David Island.
A variety of intrusive rocks (gabbrodiorite, granite-aplite and Bt-granite) of 500 m.a. batholith, exposed at Cape Delay Point, are characterized by high values of magnetic susceptibility (13÷22)×10-3 SI units. However, biotite gabbro has low values. The granosyenites and granodiorites of Hippo Island mainly have high values of magnetic susceptibility (40÷50)×10-3 SI units. The Batholith dyke complex in the area of Cape Kennedy is mainly composed by non-magnetic rocks, with the exception of Bt leucogranite 64×10-3 SI units. Also, the aplite of Gilles Island has high values of magnetic susceptibility (55÷70)×10-3 SI units.
The Archean Cape Charcot metamorphic rocks include weakly magnetic paragneisses (4÷5)×10-3 SI units and non-magnetic orthogneisses ~0.3×10-3 SI units. Metamorphic rocks of the Davis Peninsula basement are characterized by values of (0.05÷9)×10-3 SI units and are represented by Amf-Bt orthogneisses and banded gneisses. Thus, the main sources of anomalies in the studied area are intrusive rocks of batholith, while Archean crystalline basement only forms a common magnetic background. The magnetic rocks of the Obruchev Hills and Cape Jones are represented by (±Px)-Amf-Bt orthogneisses (30÷90)×10-3 SI units, which form the main anomaly magnetic field pattern. Magnetic susceptibility values for Sill-Bt and Grt-Bt paragneisses do not exceed 0.4×10-3 SI units.
