Stratigraphy of the Western channel iron deposits of the Marillana Creek Operations,Western Australia

Abstract

The internal stratigraphy of the Marillana Creek palaeochannel Tertiary channel iron deposits (CIDs) in the Hamersley Province of Western Australia was initially defined in the 1980s and redefined as the Marillana Formation in the early 2000s. Recent drilling, open pit mining and field observations in the Western deposits at the Marillana Creek tenements have revealed some additional details on the extent and detail of some units of the Marillana Formation stratigraphy in this area. The drill hole data at Western 1 South has identified a number of features either not previously documented in this area or whose significance has not been adequately recognised, including a denatured zone at the base of the Upper CID of the Barimunya Member, and variations in the lithology within the Munjina Member at the base of the channel. Additionally, the Western 4 pit walls show evidence of a significant near-surface clay horizon and overlying CID which are suggested to be the equivalent of the Iowa Eastern Member in the Eastern deposits. The deposition of this unit was most likely driven by a regional climatic disruption rather than a change in sediment source area alone. The nature of the Weeli Wolli Formation-derived goethitic peloids in the Western deposits may explain the more extensive denaturing in the Western Lower CID of the Barimunya Member. In contrast, the more robust nature of the hematitic-cored pelletoids in the Central and Eastern deposits has resulted in a less denatured Lower CID in these areas. Such work reveals the value of and need for ongoing face mapping by geologists and detailed drill hole logging, and demonstrates the benefits of querying previously accepted interpretations.

Keywords

CHANNEL IRON DEPOSITS GOETHITE HEMATITE PELOID PELLETOID YANDI HAMERSLEY PROVINCE WESTERN AUSTRALIA

References

Alonso-Zarsa

A. M

. 2003. Palaeoenvironmental significance of palustrine carbonates and calcretes in the geological record Earth Sci. Rev., 2003, 60, 261–298.

Anderson

. 1982. The Yandicoogina pisolitic iron ore deposit, Western Australia — geological evaluation of all investigations pre 1982’, unpublished report, BHP Billiton Iron Ore, pp. 128.

Arvidson

. 2003. Resource modelling of Yandi Western deposits 1 to 6’, unpublished report, BHP Billiton Iron Ore, pp. 91.

Dawson

. 1981. The Yandicoogina pisolitic iron ore deposit, Western Australia — summary and evaluation of programmes completed in the period 1979–1981, unpublished report, BHP Billiton Iron Ore, pp.202.

Hall

G. C.

and Kneeshaw

. 1990. Yandicoogina-Marillana Pisolitic Iron Deposits’, ‘Geology of the Mineral Deposits of Australia and Papua New Guinea, Monograph 14, 1581-1586; 1990. Melbourne, AusIMM.

Heim

J. A.

, Vasconcelos

P. M.

, Shuster

D. L.

, Farley

K. A.

and Broadbent

. 2006. Dating paleochannel iron ore by (U-Th)/He analysis of supergene goethite, Hamersley Province, Australia, Geology, 2006. 34, 173–176.

Kepert

D. A

. 2001. The mapped stratigraphy and structure of the MINING AREA C Region: The Black Monolith, unpublished report, BHP Billiton Iron Ore, pp.320.

Kneeshaw

. 2004. Guide to the geology of the Hamersley and North East Pilbara iron ore provinces: the Blue Book, unpublished report, BHP Billiton Iron Ore, pp.61.

Kneeshaw

, Kepert

D. A.

, Tehnas

I. J.

and Pudovskis

M. A

. 2003. Appendix I: Marillana Formation, Channel deposits in the Marillana Creek palaeochannel of the central Hamersley Ranges, Western Australia, in Channel iron deposits of the Hamersley Province, Western Australia', (ed. Ramanaidou

E. R.

et al), Aust. J. Earth Sci., 50, 669–690.

10.

Kneeshaw

, Kepert

D. A.

, Tehnas

I. J.

and Pudovskis

M. A

. 2002. From Mt Goldworthy to Area C — reflections of forty years of iron ore exploration in the Pilbara, Proc. Iron Ore 2002. 7, 41–56.

11.

Macphail

. 1997. Late Neogene climates in Australia: fossil pollen-and spore-based estimates in retrospect and prospect, Aust. J. Botany, 45, 425–464.

12.

Macphail

M. K.

and Stone

M. S

. 2004. Age and palaeoenvironmental constraints on the genesis of the Yandi channel iron deposits, Marillana Formation, Pilbara, northwestern Australia, Aust. J. Earth Sci., 51, 497–520.

13.

McGowran

and Li

. 1998. Cainozoic climate change and its implication for understanding the Australina regolith, in The State of Regolith, (ed. R. A. Eggleton), Proc. 2nd Aust. Conlon ‘Landscape evolution and mineral exploration’, Geological Society of Australia Special Publication, 20, 86–103.

14.

Morris

R. C

. 1994. Detrital Iron Deposits of the Hamersley Province, CSIRO/AMIRA Iron Ores of the Hamersley Province Project P75G, Report 76R, CSIRO Division of Exploration and Mining, Perth, Australia, 227.

15.

Morris

R. C

. 1997. CID in the Western Yandi Area. Report 2, February 1997, unpublished report, BHP Billiton Iron Ore.

16.

Morris

R. C.

and Ramanaidou

E. R

. 2007. Genesis of the Channel Iron Deposit (CID) of the Pilbara of Western Australia, Aust. J. Earth Sci., 54, 733–756.

17.

Morris

R. C.

, Ramanaidou

E. R.

and Horwitz

R. C

. 1993. Channel Iron Deposits of the Hamersley Province, AMIRA-CSIRO Iron Ores of the Hamersley Province Project P75G, Report 399R, CSIRO Division of Exploration and Mining, Perth, Australia.

18.

Ramanaidou

E. R.

Morris

R. C

and Horwitz

R. C

. 2003. Channel iron deposits of the Hamersley Province, Western Australia, Aust. J. Earth Sci., 50, 669–690.

19.

Sun

S. S.

and McDonough

W. F

. 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composi-tion and processes, in Magmatism in the Ocean Basins', (ed. Saunders

A. D.

and Norry

M. J.

), Special Publication, 42, 313–345, London, Geological Society.

20.

Stone

M. S

. 2005. Depositional history and mineralisation of Tertiary channel iron deposits at Yandi, Eastern Pilbara, Australia, Unpublished PhD thesis, 328.

21.

Stone

M. S.

, George

A. D.

, Kneeshaw

and Barley

M. E

. 2002. Stratigraphy and sedimentology features of the Tertiary Yandi Channel Iron Deposits, Hamersley Province, Western Australia, Proc. Iron Ore 2002, 7, 137–144.

22.

Thorne

A. M.

and Tyler

I. M

. 1997. Roy Hill, Western Australia, 2nd Edn: 1 : 250, 000 geological series, Western Australian Geological Survey, Explanatory Notes, 22.

23.

Trendall

A. F

. 2002. The significance of iron-formation in the Precambrian stratigraphic record, Int. Assoc. Sedimentot Spec Publ., 33, 33–66.