ABSTRACT.
The elevate� range east of Point Pass is defined by a sequence of 3,650 metres of Late Prt5ambrian glacial and post-glacial sediments.
The glacial sequence is composed of 1,850 metres of pebbly tillite and bedded arenaceous interglacials, which unconformably,overlie the laminated Saddleworth Siltstones. The 1,800 metres of sediment conformably overlying the glacial sequence are generally composed of calcereous and non-calcereous argillites and feld
sarenites which have been deposited under a shallow sea in the slowly subsiding Adelaide Geosynclinal Basin.
Major block-faulting has resulted in the trun
cation and subsequent disappearance of the upper beds of the Tarcowie Siltstone, which represents the
youngest Pre-Cambrian sediments exposed in the area.
PLATE D,
A, Pebbly clasts showing tectonicly induced elongations within a silty-sand matrix.'
Lower Gilbert Range Quartzite. (T.S, 379/11).
B. Micro-graded bedding development in varve sediments. Lower Hansborough Tillite, (T,S. 379/A3),
C. Broad lamination development due to grain size variations, Upper Saddleworth
siltstone, (T.S, 379/Al),
PLATE E.
A, Cross-stratification defined by heavy mineral concentrations in a fine grained siltstone.
Middle Tarcowie Siltstone, (T.S. 379/A26).
B. A banded Stilpnomelane schist erratic.
Lower.Hansborough Tillite. (T.S. 379/B5).
C. Calcite filled cleav age plane in a fine grained, laminated dolomite.
Shale. (T.S. 379/AlS). Tindelpina
ACKNOWLEDGMEN'l'S.
This study was carried out under the supervision of Dr� V. Gostin whose advice and criticism are grate
fully acknowledged.
Field work was carried out in association with A.J. Drummond and.L,J. Morris. Helpful discussion with E.M. McBriar, R.J. Love, N,M. Lemon,
c.
Coin,P.G. Haslett and J, Sumartojo was also gratefully appreciated,
The general assistance of P. Stafford and R,C.
Hamdorf is also acknowledged.
