Magnetic properties of Precambrian rocks from the Denman Glacier area and the Obruchev Hills

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...

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Bibliographic Details
Main Authors: Golynsky, D., Borovkov, N., Golynsky, A., Kim, H.
Format: Conference Object
Language:English
Published: 2023
Subjects:
Online Access:https://gfzpublic.gfz-potsdam.de/pubman/item/item_5017975
Description
Summary: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.