The Lau-Havre-Taupo back-arc basin: A southward-propagating, multi-stage evolution from rifting to spreading

Collisional model for rapid fore‐arc block rotations, arc curvature, and episodic back‐arc rifting in subduction settings

“…The Havre Trough (from $35-26°S) has a nearly constant width, with only a slight northward increase ( Figure B1) [Delteil et al, 2002]. This implies that the rate of rifting in the Havre Trough does not change markedly along-strike [Parson and Wright, 1996], reflecting a lack of fore-arc rotation about a nearby pole. It is not possible to directly measure the actual rate of rifting in the Havre Trough, but estimates vary from 0.8 to 2.1 cm/a [e.g., Pelletier and Louat, 1989;Wright, 1993].…”

“…This observation of basin shape is consistent with inferred rapid clockwise rotation of the Tonga Arc during backarc rifting. Ruellan et al [2003] show that the southward migration of the LSC collision (initiating $5-4 Ma ago) along the Tonga Trench is closely tracked by the 10 cm/a southward propagation of Lau Basin opening [Parson and Wright, 1996;Taylor et al, 1996]. The presence of the northern edge of the torn Pacific slab may cause a northward increase in slab rollback along the Tonga arc [Stegman et al, 2006;Schellart et al, 2007], that could, in turn, accelerate the rotation of the Tongan fore arc.…”

Propagating rift during the opening of a small oceanic basin: The Protector Basin (Scotia Arc, Antarctica)

“…Spreading axes of large oceanic basins generally end in transcurrent or subduction plate boundaries or in different types of triple junctions [5]. Yet there are few examples where spreading axes end in propagating rifts like the Gulf of Viscay [6][7][8], which is one of the better known inactive propagating rifts formed during the development of the northern Atlantic ocean; other examples are the opening of the Labrador Sea [9] or the back-arc basin related to the Tonga-Kermadec subduction [10]. In addition, there exist oceanic propagating rifts produced by a change in the spreading features, such as those described in the Galapagos area [11], the Mid-Atlantic ridge [12], the Selkirk palaeomicroplate in the South Pacific [13] or the Pacific-Antarctic ridge [14].…”

Mesoproterozoic high Fe–Ti mafic magmatism in western Shandong, North China Craton: Petrogenesis and implications for the final breakup of the Columbia supercontinent

“…Although high degrees of fractionation (65-73%) of olivine, clinopyroxene and plagioclase have been reported for high Fe-Ti basaltic rocks (Clague and Bunch, 1976;Clague et al, 1981;Perfit and Fornari, 1983), and experimental studies have shown that broadly basaltic compositions are still preserved after 90% fractionation (Dixon and Rutherford, 1979), the derivative basaltic magma is generally tholeiitic in composition, as is the case at propagating spreading centers along mid-ocean ridges (Clague et al, 1981;Perfit and Fornari, 1983;Sinton et al, 1983) or in back-arc basins (Pearce et al, 1994;Parson and Wright, 1996;Lagabrielle et al, 1997). Clearly, for the Yishui high Fe-Ti gabbros in this study, fractional crystallization alone fails to explain the Fe-Ti enrichment, coupled with an alkaline composition.…”