Tectonic map of Antarctica - 2nd edition

Tectonic map of Antarctica - 2nd edition

The 1st edition of the 1:10,000,000 tectonic map of Antarcticapublished in 2012, was compiled as a contribution from the CGMW to the IPY 2007-2009 scientific programme. Over the period 2010-2020, considerable progress has been made in the acquisition of geophysical information (mainly seismic and magnetic data from ships in marine areas and airborne data from magnetic, gravity and radio echo soundings on land).

Marine gravity anomalies were derived from ERS altimetry observations over deep ocean floor, and extensive state-of-the-art analytical studies were performed on the collections of Antarctic rocks. These achievements enhanced insight in the structure and geodynamic history of the South Polar Region and stimulated preparation of the 2nd edition of the 1:10,000,000 Tectonic Map (TeMAnt).
- The ages of oceanic crust are refined based on revised identification of magnetic anomalies;
Major tectonic elements plausibly predicted under ice sheet by available remote sensing data are shown in an interpretative inset together with evaluation of seafloor spreading rates in the Southern Ocean;
- The map is accompanied by explanatory notes containing description and illustrations of major tectonic elements, as well as references to key data sources used for the compilation.

The advances made by TeMAnt compared to the 1st edition are as follows:
- Areas with sub-aerial rock outcrops that had been mapped within the limits of credible interpolation are clearly shown on the main map.
against a vast ice-covered terrain totally devoid of ground-truth geological evidence. The subglacial bedrock is characterised only by shadow relief seen through the transparent ice cap, while a light-colour image of the bedrock topography is provided in a separate insert illustrating the morphostructural appearance of the map.
Tectonic features;
- The ages of protolith emplacement, primary cratonisation and subsequent reworking events are defined for most of the crystalline basement of the complex East Antarctic;
- A better interpretation of the history of the polyphase magmatic arc is proposed for the present-day Pacific margin;
- More precise structural imaging is being carried out on the Antarctic continental margin, including the positioning of marginal faults, the location of continent-ocean boundaries and the distribution of sediment thickness;