Figure 2. Plate reconstructions of the souther n Indian Ocean region (after Royer and Coffin, 1992; Royer and Sandwell, 1989) using a hot spot reference frame (Müller et al., 1993) and keeping Antarctica fixed. Reconstructed position of the Kerguelen hot spot (after Mü ;ller et al., 1993) is indicated by stars. Volcanic rock associated with the Kerguelen hot spot is indi cated in gray shading, and lamprophyres are indicated as diamonds, as they have appeared through geolog ic time. Dashed line = a possible northern boundary for Greater India. IND = India; ANT= Antarct ica; AUS = Australia. 130.9 (M10) and 118.7 (M0) Ma: Seafloor spreading initiates during Ch ron M11 (~133 Ma) between Western Australia and Greater India. The Bunbury Basalt (BB) of sout hwest Australia is erupted close to these breakup events in both time and space. Of the two Bunb ury Basalt types, the Casuarina may be related to the breakup of Australia and India, influenced by th e Kerguelen hot spot, and the Gosselin may represent magmatism associated with the breakup of Australi a and Antarctica. Between 130.9 and 118.7 Ma, Antarctica migrates to the southeast relative to the Kerguelen hot spot. 110 and 100 Ma: Seafloor spreading continues among India, Antarctica, and Austra lia. Rajmahal (RAJ) rocks postdate breakup of India and Australia by ~15 m.y. (Markl, 1974, 19 78) and the breakup of India and Antarctica by ~15-40 m.y. Indian and Antarctic lamprophyres (diamonds) also postdate major breakup events. The first massive pulse of Kerguelen magmatism cr eates the southern Kerguelen Plateau (SKP) (Figs. 3, 4) at ~110 Ma, as Indian Ocean lithosphere mig rates southeast relative to the Kerguelen hot spot. 83 (C34) and 63.6 (C28) Ma: India continues its northward drift relative to Antarctica, and the Kerguelen hot spot is predicted to have remained close to the northeast edge of the central Kerguelen Plateau (CKP) (Figs. 3, 4) and Broken Ridge (BR) ( Figs. 5, 6), which form at ~85 Ma. Subsequently, the hot spot generates the Ninetyeast Ridge (NER). 40.1 (C18) and 23.4 (C6c) Ma: At ~40 Ma, seafloor spreading commences between the CKP and BR. T he hot spot generates the northern Kerguelen Plateau (NKP) (Figs. 3, 4), and since 40 Ma, as BR and the Kerguelen Plateau continue to separate, produces the Kerguelen Archipelago (KA), Heard and McDonald islands (Figs. 3, 4), the chain of volcanoes between Kerguelen and Hear d (Figs. 3, 4).
To 183 Figure 3
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