Woodgreen, Northern Territory : explanatory notes
Northern Territory Geological Survey
E-Publications; E-Books; PublicationNT; Australia 1:100 000 Geological Map Series
2007
Australia 1:100 000 Geological Map Wood 5458; Australia 1:250 000 Geological MapAlcoota SF5310; Australia 1:250 000 Geological MapAlcoota SF5310
1:100 000
Made available via the Publications (Legal Deposit) Act 2004 (NT); Available from GEMIS - Geoscience Exploration and Mining Information System
English
Geology; Georgina Basin; Arunta Region
Northern Territory Government; Northern Territory Government
Darwin
1st ed.
Australia 1:100 000 Geological Map Series
application/pdf
9780724571321
0811-6296
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government
https://creativecommons.org/licenses/by/4.0/
https://geoscience.nt.gov.au/gemis/ntgsjspui/handle/1/81885 [GEMIS]
https://hdl.handle.net/10070/794795
https://hdl.handle.net/10070/794807
2 5 (eg 550 ppm and 80 ppm), but contains no significant Sn m i n e r a l i s a t i o n (Fr a t e r 2 0 0 5 ). U raniu m In 1971, Pechiney, in joint venture with Kratos Uranium, flew a radiometric survey over delny a n d dneiPer, e a s t o f Woodgreen. an o m a l i e s w e r e l o c a t e d o v e r b a s e m e n t i g n e o u s a n d m e t a m o r p h i c r o c k s s i m i l a r t o t h o s e i n Woodgreen. no u r a n i u m m i n e r a l i s a t i o n w a s d e t e c t e d (le h m a n n a n d Mannoni 1971). Radiometric anomalies, possibly due to u r a n i u m , h a v e b e e n d e t e c t e d i n g a m m a - r a y l o g s o f ce n o z o i c s e d i m e n t s i n w a t e r b o r e s i n Woodgreen (sh a w a n d Wa r r e n 1975). Prompted by the Yeelirrie discovery in Western au s t r a l i a , cra ex p l o r a t i o n c o n d u c t e d r e g i o n a l e x p l o r a t i o n f o r te r t i a r y c a l c r e t e - h o s t e d u r a n i u m . Wo r k s u b s e q u e n t l y f o c u s e d o n t h e ti - tr e e Ba s i n b u t w a s u n s u c c e s s f u l (Hughes 1972). Otter Exploration flew a spectrometer survey in 1977 as part of a search for uranium or scheelite m i n e r a l i s a t i o n . Fo l l o w - u p g r o u n d w o r k f a i l e d t o d e t e c t a n y significant mineralisation and the licence was relinquished in 1979 (Kojan 1979). In the early 1980s, CRA Exploration u n d e r t o o k m u l t i - c o m m o d i t y a i r b o r n e g e o p h y s i c a l a n d d r a i n a g e g e o c h e m i c a l e x p l o r a t i o n , i n c l u d i n g s e l e c t e d a r e a s t a r g e t e d f o r u n c o n f o r m i t y - r e l a t e d u r a n i u m , b u t t h i s w a s unsuccessful (Menzies and Louwrens 1995). G old a j o i n t v e n t u r e b e t w e e n tr a c k mi n e r a l s a n d eo n me t a l s was granted tenure in 1988, with the intentions of exploring f o r g o l d i n i r o n s t o n e o u t c r o p p i n g n e a r mo l l i e Bl u f f , a n d following up a radiometric anomaly that was defined by ot t e r ex p l o r a t i o n a s a g o l d t a r g e t . th i s t a r g e t i s i n t h e to p s me m b e r o f t h e ce n t r a l mo u n t st u a r t Fo r m a t i o n n e a r 446800mE 7551000mN , 16 km northeast of the cupriferous h o r i z o n a t mo u n t sk i n n e r . it h a s r o c k c h i p a s s a y s o f l a t e r i t i c shale up to 110 ppm Pb, 100 ppm Cu and 290 ppm Zn (Dashlooty 1989). All surface rock chips and unspecified s a m p l e s f r o m p r e v i o u s d r i l l i n g a t mo u n t sk i n n e r w e r e a n a l y s e d f o r au . re s u l t s w e r e l e s s t h a n 1 p p m au a n d t h e l i c e n c e w a s r e l i n q u i s h e d w i t h o u t f u r t h e r w o r k . D iamond s In the early 1980s, a joint venture between Alcoa and We s t e r n mi n i n g e x p l o r e d f o r d i a m o n d s i n Woodgreen without success (Chuck 1983). CRA Exploration e x p l o r e d p a r t s o f BarroW creek a n d alcoota f o r diamondiferous kimberlites during the 1990s. Several c i r c u l a r g e o m o r p h o l o g i c a l f e a t u r e s i n Woodgreen w e r e i n s p e c t e d , b u t n o t c o n s i d e r e d w o r t h y o f f o l l o w u p . no d i a m o n d s o r d i a m o n d i n d i c a t o r m i n e r a l s w e r e r e c o r d e d d u r i n g r e c o n n a i s s a n c e g r a v e l s a m p l i n g . re e v a l u a t i o n o f t h e aeromagnetic data failed to identify any significant dipolar anomalies indicative of diatremes (Louwrens 1996). G rou nd w ate r de t a i l e d i n f o r m a t i o n r e g a r d i n g g r o u n d w a t e r i n Woodgreen, and the location and other details of specific w a t e r b o r e s i s o b t a i n a b l e f r o m t h e Wa t e r re s o u r c e s Br a n c h , na t u r a l sy s t e m s di v i s i o n o f t h e de p a r t m e n t o f na t u r a l re s o u r c e s , en v i r o n m e n t a n d t h e ar t s , al i c e sp r i n g s . aq u i f e r s i n Woodgreen c a n b e s u b d i v i d e d i n t o t h r e e b r o a d s t r a t i g r a p h i c c a t e g o r i e s : Pa l a e o p r o t e r o z o i c m e t a m o r p h i c and igneous basement rocks of the Arunta Region; lithified ne o p r o t e r o z o i c t o ca m b r i a n s e d i m e n t a r y r o c k s o f t h e Georgina Basin; and lithified to unconsolidated sediments of t h e ce n o z o i c ti - tr e e Ba s i n a n d a s s o c i a t e d p a l a e o c h a n n e l s . aq u i f e r s i n t h e g e n e r a l l y n o n - p o r o u s b a s e m e n t r o c k s are likely to be irregular, small and difficult to predict, a n d t h e s u c c e s s r a t e h a s b e e n l o w (sh a w a n d Wa r r e n 1975, McDonald 1990). The most important Georgina Ba s i n a q u i f e r s a r e i n ca m b r o or d o v i c i a n a n d de v o n i a n sedimentary rocks (Shaw and Warren 1975, Haines et al 1991), which are not exposed in Woodgreen. su c c e s s f u l b o r e s h a v e b e e n s u n k i n t o ne o p r o t e r o z o i c s t r a t a , b u t y i e l d s a r e u s u a l l y l o w a n d h i g h s a l i n i t y i s c o m m o n (sh a w a n d Warren 1975, McDonald 1990). This is likely to be at least p a r t l y t h e r e s u l t o f i n t e r b e d d e d e v a p o r i t e s , w h i c h h a v e b e e n i n t e r s e c t e d i n m i n e r a l e x p l o r a t i o n d r i l l h o l e s . sh a w and Warren (1975) reported that the CambroOrdovician Tomahawk Formation contains good aquifers and that 90% o f b o r e s d r i l l e d i n t o t h e u n i t h a v e b e e n s u c c e s s f u l . al t h o u g h t h i s f o r m a t i o n d o e s n o t o u t c r o p i n Woodgreen, i t i s l i k e l y t o b e p r e s e n t a t s h a l l o w d e p t h s b e n e a t h ce n o z o i c c o v e r i n t h e e x t r e m e n o r t h e a s t e r n c o r n e r o f t h e s h e e t a r e a . th e h y d r o g e o l o g y a n d g r o u n d w a t e r r e s o u r c e s o f t h e ti - tr e e Basin have been studied in detail by McDonald (1990). on l y t h e e a s t e r n m a r g i n o f t h e b a s i n , a n d a s s o c i a t e d p a l a e o c h a n n e l s , a r e p r e s e n t w i t h i n Woodgreen, b u t t h i s b a s i n p r o v i d e s t h e m o s t r e l i a b l e w a t e r r e s o u r c e s i n t h e a r e a . AcKnowlEdgEMEntS the a ut hor s gr a t e f ul l y a c know l e dge t he f r i e ndl y c oo pe r a t i on of pa s t or a l i s t s on mount ski nne r a nd Woodgr e e n s t a t i ons during fieldwork. John Dunster (NTGS, Darwin) contributed t o t he E conomic geology s e c t i on. da vi d gr e e ne (de ni s on uni ve r s i t y , ohi o, usa) i s t ha nke d f or di s c us s i on s on t he s t r uc t ur a l ge ol ogy of t he r e gi on. Fi gur e s w e r e pr e pa r e d by Kathy Johnston, who also formatted the document. rEFErEncES Buick IS, Miller JA, Williams IS and Cartwright I, 2001. or dovi c i a n hi gh- gr a de m e t a m or phi s m of a ne w l y r e c ogni s e d l a t e ne opr ot e r oz oi c t e r r a ne i n t he nor t he r n H a r t s ra nge , c e nt r a l aus t r a l i a . J ournal of M etamorphic Geology 19, 373394. Chuck RG, 1982. Annual report for EL 2654 Mount Skinner, NT for the period 24/1/81 23/1/82. Alcoa of Australia lt d. N orthern Territory Geological Survey, O pen F ile Company Report CR19820183. Chuck RG, 1983. Base metal exploration in EL 2654, Mount Skinner, central Australia, final report. Alcoa of Australia lt d. N orthern Territory Geological Survey, O pen F ile Company Report CR19830125. ClaouLong JC and Hoatson DM, 2005. Proterozoic maficultramafic intrusions in the Arunta Region,