Structure of lava flows of the Nimbin Rhyolite, northeast New South Wales
The Tertiary Nimbin Rhyolite in northeast New South Wales comprises tiers of lava extending laterally up to 12 km. The geographic distribution of crystal‐poor (nearly aphyric) and crystal‐rich lava types indicates that these tiers comprise coalesced lava domes and limited flows rather than extensive flows. Bodies of crystal‐poor lava exhibit flow foliation and flow folds which aid in locating vents, whereas the weak foliation in bodies of crystal‐rich lava makes their internal structure difficult to resolve. The spacing of vents throughout the lava complex also suggests multiple lava bodies, ranging in diameter from 2 to 4 km.