Stratno | Stratigraphic Name | Category | Contents | Last update 
88|Acton Shale Member|Name source|After the suburb of Acton, Canberra, ACT (Opik 1958).|16-MAY-23
88|Acton Shale Member|Unit history|Originally a distinct formation conformably overlying the Pittman Formation (Opik 1958). Subsequently redefined as a member high in the Pittman Formation (Strusz and Henderson 1971). In the Gundaroo-Nanima area the 'Picaree Formation' (Best and Other 1964).|16-MAY-23
88|Acton Shale Member|Type section locality|South of the ANU Staff Centre at Lat 35o 17'S Long 149o 06'E (Owen 1987).  Rubbly outcrops of thinly laminated siliceous black shale dipping 20o E.  (Original type locality of Opik 1958 at the old race course, Acton is now mostly inundated by Lake Burley Griffin).  No type section exposed. REFERENCE LOCALITIES: Ridges east of Aranda suburb (Owen 1987); vicinity of Lake Ginninderra (Henderson 1980) and Picaree Hill (GR963/231).|16-MAY-23
88|Acton Shale Member|Extent|Low ridges and scattered outcrops in the Canberra-Queanbeyan district, the Gundaroo-Namina area Lake George Range.|16-MAY-23
88|Acton Shale Member|Thickness range|Estimates of up to 60 m in Canberra district (Henderson 1981) and Gunderoo-Namina area (Smith 1964).|16-MAY-23
88|Acton Shale Member|Lithology|Thinly laminated siliceous shale - dark grey where fresh but otherwise whitish-grey where weathered - graptolites preserved as black carboneous films on bedding planes.|16-MAY-23
88|Acton Shale Member|Depositional environment|Marine-reducing environment in association with distal outer submarine fans on the abyssal plain or locally within proximal zones such as inner fan levees or abandoned feeder channels.|16-MAY-23
88|Acton Shale Member|Relationships and boundaries|Conformable lithology in the upper part of the Pittman Formation. South of Queanbeyan overlain unconformably by Late Silurian Colinton Volcanics.|16-MAY-23
88|Acton Shale Member|Age reasons|Late Ordovician (Gisbornian to Bolindian) in age based on graptolites (Opik 1958, Webby 1981)|16-MAY-23
88|Acton Shale Member|Correlations|With scattered outcrops in the Gundaroo-Namina and Queanbeyan areas and the Lake George range; may in part correlate with Merigan Black Shale and Bullongong Black Shale (Webby 1981) further to the east.|16-MAY-23
