Figures captions
Figure I : Simplified geological map of the Terre Adélie Craton (after Ménot et al. 2007).
Studied zone (red star) is located in the 1.7 Ga domain, close to the French Polar
Dumont d’Urville station. Inset: location and limits of the Terre Adélie Craton (TAC)
in East Antarctica and of the Gawler Craton (GC) in South Australia.
Figure II : Example of high-temperature rock types outcropping in Pointe Géologie
archipelago. (a) Migmatitic gneiss structures illustrating the HT polyphased tectonic in
the paleproterozoic formation of the TAC: septas of mesosomes and more continuous layers of
melanosomes bearing foliation (e.g., hammer area); successive generation of melt segregation
with earliest elongated lenses locally affected by intrafolial folds within the foliation,
undeformed and concordant leucosomes with the foliation and later thin dykes cross-cutting
foliation (arrowed). (b) Folded leucosomes with axial plane parallel to the foliation. (c)
Melt segregation process generating concordant leucosome that supplies “alimente”
cross-cutting dykelet transferring melts upward (Petrel Island). (d) Coarse-grained pink
granites forming metric to decametric thickness dykes cross-cutting the regional foliation
(Pétrel Island). (e). Anatexite showing melanocratic layers bearing foliation (Balance Island).
(f) Mylonitic gneisses characterized by vertical foliation (Rocher Jackobsen, Pétrels Island).
The solar compass used to determine the geographical orientations of tectonic structures gives
the photograph scale.
Figure III : Photomicrograph of migmatitic gneiss in the vertical shear zone (Petrels Island).
Sillimanite (sill) and elongated oxide grains (mainly magnetite (mt) and ilmenite) are
parallel to foliation in the melanocratic layers. The shape of oxide grains tends to be
more rounded and perpendicular to the foliation in more leucocratic areas (arrowed).
Figure IIIbis:
Ilmenite LPO patterns of migmatitic gneisses in the vertical shear zone, Pétrel Island
(sample AP85). LPO are represented on equal area, lower hemisphere projection.
Foliation is marked by a black line and lineation is marked by the structural axis X.
The density contours are in Multiple Uniform Distribution (MUD); N is the number of
measured grains.
Figure IV : P' parameter as a function of Km values: granitic dyke (open squares), mylonitic
gneisses (full triangles), gneisses (full squares) and anatexites (open diamonds).
Figure V : Normalized susceptibility K/Ko as a function of the temperature T in gneisses
(samples AP35 and AP85) and in granites (09cjb75, 11cjb41 and 11cjb71).
Figure VI : Hysteresis loops for gneisses (AP35 and AP85) and granite (11cjb108). Remanent
coercive force (Hcr).
Figure VII : Ratios of hysteresis parameters (Day et al., 1977): Jrs/Js (Jrs: remanence at
saturation; Js: magnetization at saturation) as a function of Hcr/Hc (Hcr: remanent
coercive force; Hc: coercive force). Areas for Multi-Domain (MD) and Pseudo Single
Domain (PSD) grain size for pure magnetite.
Figure VIII : Projection of AMS data of each site of Pointe Géologie Archipelago. AMS
projections on Petrel Island (black square) are illustrated in Figure IX. Distribution of
maximum axes (K1; blue squares) and minimum axes (K3; violet circle) is in lower
hemisphere equal area projection along with confidence ellipses. White, yellow and
white colour of stereonets background represents the AMS projections of gneisses,
granitic dykes and anatexites, respectively.
Figure IX : Projection of AMS data of each site of Petrel Island in Pointe Géologie
Archipelago. Distribution of maximum axes (K1; blue squares) and minimum axes
(K3; violet circle) is in lower hemisphere equal area projection along with confidence
ellipses. White, yellow and white colour of stereonets background represents the AMS
projections of gneisses, granitic dykes and anatexites, respectively.
Figure X : T parameter as a function of P' values (Jelinek, 1981): granitic dyke (open
squares), mylonitic gneisses (full triangles), gneisses (full squares) and anatexites
(open diamonds).