Geophysical and Geological survey on Danco coast. NW Antarctic Peninsula

TASSONE, A; LIPPAI H. F.; HORMAECHEA, J. L.; VILAS, J. F,

Buenos Aires

Conferencia; SCAR XXXI. .4 th Open Science Conference; 2010

Dirección Nacional del Antártico

The survey was directed to acquire new data to define lateral relationships and geometry for the geologic units belonging to the Mesozoic magmatic arc exposed in the western border of the Antarctic Peninsula (AP). In the study area  volcanic/volcaniclastic sequence is intruded by a granodioritic pluton; later andesitic dykes bear sulphide mineralization. The main structures consist of two fault systems of WNW-ESE and NE-SW orientation which delineate the morphology of inland areas and the shoreline. One bathymetric survey of Hughes bay was carried out to determine the geometry and spatial distribution of the main submerged depressions. In addition, a magnetic survey was performed with two free-precession proton magnetometers which worked synchronized in order to make the relevant corrections. On land data were acquired in 5803 GPS fixed stations. A MK3 Zodiac was employed for the offshore magnetic survey with a grid composed of 11672 stations, organized along broadly orthogonal sections with a total length of around 548 km. Magnetic susceptibility data (k) were also obtained on outcrops. The processing of acquired data allowed producing an onshore/offshore map of the magnetic anomalies which shows maxima (up to 3000 nT) and minima (-500 nT) organized in parallel NE-SW oriented belts. The correlation of on land geology with the magnetic anomaly map suggests the offshore continuity of outcropping volcanic rocks. The map also indicates the probable extension of volcanic dykes with sulphide mineralization in the Cierva Cove northwards along Danco Coast.