Thermotectonic history of the Bassian Rise, Australia: implications for the breakup of eastern Gondwana along Australia's southeastern margins

During the Mesozoic breakup of eastern Gondwana, rifting occurred along bot h the Southern Ocean Rift (SOR) between Australia and Antarctica, and the T asman Sea Rift (TSR) between Australia and the Lord Howe Rise. As a consequ ence of breakup, Tasmania, located at the southeastern tip of Australia, is now surrounded by rifted margins, including a failed branch of the SOR wit hin Bass Strait to the north. Apatite fission track (AFT) results from the Furneaux Islands, located along the Bassian Rise at the eastern edge of Bas s Strait, record two major episodes of rapid cooling/denudation since break up began. The first occurred during the middle Cretaceous at similar to 94/-2 Ma and documents the timing of formation of the Bassian Rise. This was followed during the Early Tertiary by the second episode at some time betwe en similar to 65-45 Ma, possibly related to Pacific plate rearrangement and north Australian collision in New Guinea. Importantly, the AFT results ind icate that formation of the Bassian Rise occurred during the middle Cretace ous at the same time as: (1) rifting along the TSR began, and (2) rifting a long the SOR within Bass Strait ceased. This suggests a link between the ti ming of formation of the Bassian Rise and the initiation and cessation of m ajor rifting events along the adjacent margins. (C) 2000 Elsevier Science B .V. All rights reserved.