Potassium‐argon dates on some Cainozoic volcanic rocks from Northeastern New South Wales

Potassium‐argon ages on the Cainozoic volcanic rocks of New South Wales

“…In the southern part of Mount Royal Range, McDougall & Wilkinson (1967) and Wellman et al (1969) have dated ten flows and one intrusion. The agds obtained from the flows range from 52 to 43 m.y.…”

“…(GA1966) found for Square Top Intrusion by McDougall & Wilkinson (1967). (15) Basaltic lavas in sequences a few hundred metres thick crop out over an area about 60 km across between Walcha and Nowendoc.…”

“…Eight K-Ar ages were measured by Dulhunty & McDougall (1966), McDougall & Wilkinson (1967), Dury et al (1969), and Dulhunty (1973) and a further six ages are reported here (Table V). All the ages measured are in the range 17 to 14 m.y.…”

“…The lavas overlie possible Cainozoic lake sediments up to 30 m thick (Branagan, 1969). Three rocks have been dated in the area -a small soda rhyolite plug dated by McDougall & Wilkinson (1967), and two trachyte flows from near Comboyne (Table VII). The measured ages all agree to within experimental error at 15.9 m.y.…”

“…Earlier estimates of age were based on evidence from physiography and degree of weathering, and on palaeontological determinations of the floras contained within non-marine sediments that are commonly closely associated with the volcanics. During the last decade the K-Ar isotopic dating method has been used to determine the age of the volcanic rocks in some areas, mainly in northeastern New South Wales (Cooper et al, 1963;Dulhunty & McDougall, 1966;McDougall & Wilkinson, 1967;Stipp & McDougall, 1968;Dury et al, 1969;Wellman et al, 1969;Dulhunty, 1972Dulhunty, , 1973. In this paper we report over 100 new K-Ar age determinations on the Cainozoic volcanic rocks of New South Wales.…”