Departmentof Industry and Resources

EXPLANATORY NOTES GEOLOGY OF THE HOOLEY 1:100 000 SHEET

by R. H. Smithies

1:100 000 GEOLOGICAL SERIES

Geological Survey of MONTAGUE DRYSDALE- MEDUSA SD 52 SOUND LONDON- BANKS DERRY 12 5,9 10 CAMDEN SOUND ASHTON CAMBRIDGE PRINCE REGENT- GULF 16 15, 13 14 PENDER o YAMPI CHARNLEY MT LISSADELL 16 ELIZABETH 2 3 4 1 2 BROOME DERBY LENNARD LANSDOWNE DIXON RIVER RANGE 6 SE 51 7 8 5 6 LA GRANGE MT NOONKAN- MT RAMSAY GORDON SE 52 ANDERSON BAH DOWNS 10 11 12 9 10 MANDORA MUNRO McCLARTY CROSSLAND MT BANNER- BILLILUNA HILLS MAN PORT 13 14 15 16 13 HEDLAND- 14 YARRIE ANKETELL o DAMPIER ROEBOURNE BEDOUT JOANNA DUMMER CORNISH LUCAS 20 BARROW SPRING ISLAND ISLAND 2 3 1 2 3 4 1 4 1 2 PYRAMID MARBLE NULLAGINE PATERSON SAHARA PERCIVAL HELENA STANSMORE ONSLOW BAR RANGE 8 5 6 7 5 6 7 SF 51 8 5 6 SF 50 BALFOUR ROY HILL RUDALL TABLETOP URAL WILSON WEBB SF 52 NINGALOO MT BRUCE DOWNS 10 11 12 9 10 11 12 9 12 9 10 TUREE NEWMAN ROBERTSON GUNANYA RUNTON MORRIS RYAN MACDONALD SF 49 MINILYA WINNING EDMUND POOL CREEK 15 16 13 14 15 16 13 16 13 14 14 COLLIER BULLEN TRAINOR MADLEY o MT PHILLIPS MT WARRI COBB RAWLINSON 24 QUOBBA KENNEDY EGERTON RANGE 2 3 4 1 2 3 4 1 4 1 2 NABBERU STANLEY HERBERT GLENBURGH ROBINSON PEAK HILL BROWNE BENTLEY SCOTT SHARK WOORAMEL RANGE BAY- 8 5 6 7 5 6 7 SG 51 8 5 6 SG 50 GLENGARRY WILUNA YOWALGA SG 52 SG 49 YARINGA KINGSTON ROBERT TALBOT EDEL BYRO BELELE COOPER 10 11 12 9 10 11 12 9 8,12 9 10 CUE SANDSTONE SIR DUKETON THROSSELL WESTWOOD LENNIS AJANA MURGOO SAMUEL WAIGEN 15 16 13 14 15 13 14 16 13 14 o KIRKALOCKA YOUANMI LEONORA LAVERTON RASON NEALE VERNON 28 GERALDTON- YALGOO WANNA HOUTMAN ABROLHOS 2 3 4 1 2 3 4 1 2 1 MENZIES EDJUDINA PERENJORI NINGHAN BARLEE MINIGWAL PLUMRIDGE JUBILEE MASON

7 8 5 6 7 8 DONGARA- 6 SH 51 5 6 SH 50 JACKSON KAL- SEEMORE LOONGANA HILLRIVER CUNDEELEE SH 52 MOORA BENCUBBIN GOORLIE KURNALPI FORREST 12 9 10 11 5,9 10 11 12 9 10 BOOR- PERTH KELLER- SOUTHERN WIDGIE- ZANTHUS NARETHA MADURA EUCLA BERRIN CROSS ABBIN MOOLTHA 13 14 15 14 15 16 16 13 14 o CORRIGIN HYDEN LAKE NORSEMAN BALLA- CULVER BURN- 32 PINJARRA JOHNSTON DONIA NOONAERA ABBIE 2 3 4 1 2 3 4 1 2 COLLIE DUMBLE- NEWDE- RAVENS- ESPERANCE- MALCOLM- YUNG GATE THORPE MONDRAIN CAPE ARID ISLAND 6 7 8 5 7, 11 BUSSELTON- SI 50 SI 51 BREMER 6, 10 AUGUSTA PEMBERTON- MT BAY 5, 9 IRWIN INLET BARKER- 10, 14 11, 15 12 ALBANY

120 o o 114 o 126

COOYA MOUNT POOYA WOHLER SATIRIST 2355 2455 2555

PYRAMID SF 50-7

MOUNT HOOLEY MILLSTREAM BILLROTH 2554 2354 2454

RHS240 15.05.03 GEOLOGICAL SURVEY OF WESTERN AUSTRALIA

GEOLOGY OF THE HOOLEY 1:100 000 SHEET

by R. H. Smithies

Perth 2003 MINISTER FOR STATE DEVELOPMENT Hon. Clive Brown MLA

DIRECTOR GENERAL, DEPARTMENT OF INDUSTRY AND RESOURCES Jim Limerick

DIRECTOR, GEOLOGICAL SURVEY OF WESTERN AUSTRALIA Tim Griffin

REFERENCE The recommended reference for this publication is: SMITHIES, R. H., 2003, Geology of the Hooley 1:100 000 sheet: Western Australia Geological Survey, 1:100 000 Geological Series Explanatory Notes, 15p.

National Library of Australia Card Number and ISBN 0 7307 8932 2

ISSN 1321–299X

Grid references in this publication refer to the Geocentric Datum of Australia 1994 (GDA94). Locations mentioned in the text are referenced using Map Grid Australia (MGA) coordinates, Zone 50. All locations are quoted to at least the nearest 100 m.

Copy editor: A. Thomson Cartography: D. Sutton Desktop Publishing: K. S. Noonan Printed by Haymarket, Perth, Western Australia

Published 2003 by Geological Survey of Western Australia

Copies available from: Information Centre Department of Industry and Resources 100 Plain Street EAST PERTH, WESTERN AUSTRALIA 6004 Telephone: (08) 9222 3459 Facsimile: (08) 9222 3444 This and other publications of the Geological Survey of Western Australia may be viewed or purchased online through the Department’s bookshop at www.doir.wa.gov.au

Cover photograph: Looking northwest to Mumbillina Bluff where metasedimentary rocks of the Hardey Formation unconformably overlie granite. Contents

Abstract ...... 1 Introduction ...... 1 Access and land use ...... 1 Climate and vegetation ...... 2 Physiography ...... 2 Regional geological setting and previous investigations ...... 4 Archaean rocks ...... 5 Unassigned greenstone units ...... 6 Ultramafic rocks (Au, Auk, Aur) ...... 6 Mafic rocks (Aba, Abal, Abag, Abas, Abu, Abuq) ...... 6 Sedimentary rocks (Asq, Asqn) ...... 6 Yule Granitoid Complex ...... 7 Cheearra Monzogranite (AgYchn) ...... 7 Cockeraga Leucogranite (AgYco, AgYcor, AgYcorx) ...... 7 Hornblende–biotite tonalite (AgYt) ...... 7 Mungaroona Granodiorite (AgYmux) ...... 7 Powdar Monzogranite (AgYpop, AgYpos) ...... 7 Unassigned granitoid (AgY) ...... 8 Metamorphism ...... 8 Structure ...... 9 Hamersley Basin ...... 9 Fortescue Group ...... 9 Mount Roe Basalt (AFr) ...... 9 Hardey Formation (AFh, AFhu) ...... 9 Kylena Formation (AFk, AFkbi, AFkh) ...... 9 Tumbiana Formation (AFt, AFtsv, AFtc, AFtsvs, AFtsvb) ...... 9 Maddina Formation (AFm, AFmk, AFmx) ...... 11 Jeerinah Formation (AFjslg, AFjo, AFjsl, AFjkd) ...... 11 Hamersley Group ...... 11 Marra Mamba Iron Formation (AHm) ...... 11 Structure and metamorphism ...... 11 Dolerite dykes (d) ...... 11 Cainozoic deposits ...... 12 Residual deposits (Czru, Czrk, Czrfb) ...... 12 Colluvium (Czc, Czcb) ...... 12 Alluvial deposits (Czaf, Czag, Czak) ...... 12 Quaternary colluvium and sheetwash deposits (Qc, Qw) ...... 12 Quaternary alluvial deposits (Qaa, Qao, Qab) ...... 12 Economic geology ...... 12 References ...... 13

Appendix

Gazetteer of localities ...... 15

Figures

1. Regional geological setting of HOOLEY ...... 2 2. Physiographic features of HOOLEY ...... 3 3. Igneous layering in hornblende–biotite tonalite ...... 8 4. Structural overview of HOOLEY and adjacent 1:100 000 map areas ...... 10

Tables

1. Summary of the geological history of HOOLEY ...... 4 2. Geochronological data relevant to HOOLEY ...... 5

iii iv GSWA Explanatory Notes Geology of the Hooley 1:100 000 sheet

Geology of the Hooley 1:100 000 sheet

by R. H. Smithies

Abstract

The HOOLEY 1:100 000 sheet lies in the southwestern part of the Archaean East Granite– Greenstone Terrane of the Pilbara Craton. Rocks of the c. 2775–2630 Ma Fortescue Group cover all but the northeastern and southwestern corners of the map sheet. These rocks are mostly shallow dipping, weakly deformed and metamorphosed. A locally angular unconformity separates the Fortescue Group rocks from the Yule Granitoid Complex of the East Pilbara Granite–Greenstone Terrane, which is exposed only in the northeastern part of HOOLEY. The Yule Granitoid Complex consists mainly of c. 2945–2930 Ma granitic rocks but also includes xenoliths and roof-pendants of greenstones belonging to the Pilbara Supergroup. The Punduna greenstone pendant is the largest of these roof pendants. The supercrustal rocks have been metamorphosed to at least lower amphibolite facies, but are now typically strongly retrogressed. Their stratigraphic position within the Pilbara Supergroup is unclear. In the far southwestern corner of HOOLEY, rocks of the Hamersley Group conformably overlie the Fortescue Group. KEYWORDS: Archaean, Pilbara Craton, Pilbara Supergroup, Fortescue Group, Hamersley Group, East Pilbara Granite–Greenstone Terrane, regional geology, structural geology, metamorphism, granitic rock

Ryan, 1967). During 2000 and 2001 the HOOLEY 1:100 000 Introduction geological sheet was mapped using both 1:25 000 colour, and 1:50 000 black and white aerial photographs. The HOOLEY* 1:100 000 geological sheet (SF 50-7, 2554) Relatively easy access to the northeastern corner of the covers the southeastern part of the PYRAMID 1:250 000 map sheet, in the northern Pilbara region (Fig. 1). Bounded by sheet facilitated mapping of that region; however, the latitudes 21°30'S and 22°00'S, and longitudes 118°00'E rugged topography of the Mungaroona and Chichester and 118°30'E, the map area lies within the West Pilbara Ranges (which rise 500 m above sea level) impeded access Mineral Field. to much of HOOLEY. Mapping was restricted to traverses along tracks and to widely spaced sites reached by Exposure is good throughout the sheet area. The north- helicopter. Limited access to large parts of the map sheet eastern corner of HOOLEY contains outcrops of the East have placed significant reliance on Landsat imagery and Pilbara Granite–Greenstone Terrane of the Archaean aerial photographic interpretation. Pilbara Craton. Most of the sheet area, however, is covered by the volcano-sedimentary assemblages that form the lower to middle part of the 2775 to 2400 Ma Hamersley Access and land use Basin (Arndt et al., 1991). These assemblages include the entire Fortescue Group and the Marra Mamba Iron The unsealed road connecting the towns of Wittenoom and Formation, the lowest part of the overlying Hamersley Roebourne passes through the southwest corner of HOOLEY. Group (see Interpreted bedrock geology on main map). Intersecting that road, to the south of the map area, is the The Fortescue Group unconformably overlies the Yule road to Hooley Homestead (the only currently inhabited Granitoid Complex of the East Pilbara Granite–Greenstone homestead), which lies in the south-central part of the sheet Terrane. (Fig. 2). The only other serviced road is in the far northeast corner of the sheet, and connects the Mugarinya Aboriginal The area was originally mapped in 1963 as part of the Community on Yandeearra Station to the north (on PYRAMID 1:250 000 geological map sheet (Kriewaldt and SATIRIST) to Yandeearra Outstation to the east (on WHITE SPRINGS). There is limited access to areas in the northeast, * Capitalized names refer to standard 1:100 000 map sheets, unless south, and west of the sheet by four-wheel drive vehicle otherwise indicated. on unmaintained tracks. Large parts of the sheet area,

1 Smithies

117° 118° 119° 120°

20° INDIAN OCEAN ?

Port ? Hedland

ZONE Karratha TERRANE CENTRAL PILBARA TECTONIC Mallina 21° WEST PILBARA GRANITE–GREENSTONEBasin

Punduna TERRANE greenstone pendant

EAST PILBARA GRANITE–GREENSTONE

22° HOOLEY

RHS241 21.05.03

Mesoproterozoic–Phanerozoic rocks Town 100 km Hamersley Basin Terrane boundary

West Pilbara Granite– Central Pilbara East Pilbara Granite– Other terranes Geenstone Terrane Tectonic Zone Greenstone Terrane Greenstones Greenstones Greenstones Mosquito Creek Basin Pilbara Craton Granitoids Granitoids Granitoids Kurrana Terrane

Figure 1. Regional geological setting of HOOLEY

including most parts of the Mungaroona Range and the , and other major channels and associated Chichester Range, are only accessible on foot or by floodplains, are lined with riverain Sclerophyll woodlands helicopter. of River Gum (Eucalyptus camaldulensis). The northeast corner of the area consists of a shrub steppe of soft The Mungaroona Range Nature Reserve occupies a spinifex (Triodia pungens) with scattered Acacia, northwest-trending strip through the centre of HOOLEY. The Grevillea, and Hakea species. The third, and largest, remaining land is divided between Yandeearra Station regime is a tree steppe of Snappy Gum (Eucalyptus (Mugarinya Aboriginal Community) in the northeast, and brevifolia) with spinifex, and scattered Acacia, Grevillea, in the south. Prior permission must be and Hakea sp. that grow on the dissected plateau that granted by the Mugarinya Aboriginal Community for dominates the sheet area. access to Yandeearra Station. Cattle grazing is the sole agricultural activity. There are no old or active mines. Physiography

Climate and vegetation In the northeast of HOOLEY, tributaries to the , including the Pilbaddy Creek, drain northward, whereas The climate of HOOLEY is arid with an average annual the west-draining Fortescue River cuts the southwest rainfall of 405 mm, most of it summer rainfall relating to corner of the sheet area (Fig. 2). These drainage systems thunderstorms or decaying tropical cyclones. Mean flow mainly during the summer wet season. Physiographic summer maximum temperatures are in the mid-30s (°C), divisions on HOOLEY match major geological divisions. whereas the winters are mild, with mean minimum July Rocks of the Fortescue Group typically form a prominent temperatures of around 15°C. dissected plateau, except in the far southwest of the HOOLEY lies within the Fortescue Botanical District and sheet area, where an alluvial plain marks the Fortescue is broadly divisible into three regimes (Beard, 1975). The River floodplain (Fig. 2). The dissected plateau surface

2 GSWA Explanatory Notes Geology of the Hooley 1:100 000 sheet

21°30'

462 118°30' MungoonaCreek

River Mungaroona Range Nature Reserve 266

Sherlock Powdar Creek 223 Yandeearra 476 Aboriginal Land

467

Creek 281 Sherlock River

Pilbaddy

441 473

Hooley Homestead Hooley Creek 471

473

Fortescue River

384 481 118°00' 22°00' RHS242 19.05.03 Recent land surface Tertiary land surface

Depositional Erosional Dissected Alluvial channel Sandplain with low- Drainage lying granite outcrop plateau Unsealed road Alluvial–colluvial plain 473 Spot height (m) High-level alluvial plain 10 km Nature reserve boundary

Figure 2. Physiographic features of HOOLEY

3 Smithies is approximately 500 m above sea level and part of HOOLEY lies in the southeastern part of the East the peneplain that Campana et al. (1964) called the Pilbara Granite–Greenstone Terrane (EPGGT; Fig. 1). Hamersley Surface. In the far northeast of the sheet area, Regionally, the terrane consists of large ovoid granitic- a sandplain partly covers low-lying granitic outcrop that gneiss complexes partially surrounded by belts of typically marks the alluvial–colluvial plains division tightly folded and near-vertically dipping volcanic (Fig. 2). rocks and sedimentary rocks typically metamorphosed to greenschist facies. The oldest dated greenstones in the EPGGT are the c. 3515–3498 Ma Coonterunah Regional geological setting and Group (Table 1; Buick et al., 1995; Van Kranendonk, 1998; Nelson, 2002). Protoliths to the greenstone previous investigations successions accumulated until c. 2940 Ma, although the majority were deposited before c. 3240 Ma. Felsic The Archaean Pilbara Craton contains some of the oldest magmatism was also periodically active between c. 3600 exposed crustal elements of Australia. It is divided into and c. 2830 Ma, with the majority of granitic rocks in two components (Fig. 1) — a granite–greenstone terrane the eastern part of the EPGGT intruded before c. 3240 Ma. that formed between c. 3600 and c. 2800 Ma (Hickman, In contrast, granitic rocks dated between c. 2945 and 1983, 1990; Barley, 1997), and the unconformably 2930 Ma form a volumetrically significant, and locally overlying volcano-sedimentary sequences (Mount Bruce dominant, component of granitic complexes in the western Supergroup) of the c. 2775 to 2400 Ma Hamersley Basin part of the terrane, including the majority of the Yule (Arndt et al., 1991; Thorne and Trendall, 2001). The Granitoid Complex (Table 1). Champion and Smithies granite–greenstone terrane of the Pilbara Craton is (1998) interpreted these c. 2945–2930 Ma granitoids as exposed mainly in the north and northeast of the craton the products of the remelting of older-than-3240 Ma felsic where erosion has removed all but local remnants of the crust, associated with tectonic activity in the Central Mount Bruce Supergroup. Pilbara Tectonic Zone. Hickman (1983) provided a comprehensive interpret- The boundary between the EPGGT and the Central ation of the geological evolution of the granite–greenstone Pilbara Tectonic Zone is a fault, which locally may be terranes of the Pilbara Craton, and included what was a faulted disconformity, between the Mallina Basin and thought to represent a regionally applicable supercrustal the underlying granite–greenstone sequences. The stratigraphy — the Pilbara Supergroup. Recently, the youngest component of the basement to the Mallina Basin recognition of separate lithotectonic elements with distinct includes a c. 3015 Ma chert assigned to the Cleaverville lithostratigraphy and history has led to the subdivision of Formation of the Gorge Creek Group (Smithies et al., the granite–greenstone terranes into: the East and West 1999). Pilbara Granite–Greenstone Terranes, the northeast- trending Central Pilbara Tectonic Zone, the Mosquito The Mount Bruce Supergroup is the early Creek Basin, and the Kurrana Terrane (Fig. 1; Hickman, (Neoarchaean to Palaeoproterozoic) component of the 2000). A detailed description of the subdivision, Hamersley Basin. The supergroup is a cover sequence of geological setting, and history of the region is presented dominantly basaltic and sedimentary rocks, of very low by Van Kranendonk et al. (2002). metamorphic grade, which unconformably overlie the

Table 1. Summary of the geological history of HOOLEY

Age (Ma) Events

<3515 – >2945 Deposition of greenstone sequences (Pilbara Supergroup), and formation of c. 3060 Ma protolith to the Cockeraga Leucogranite c. 3420 Intrusion of protolith to the gneissic rocks of the Yule Granitoid Complex c. 3240 Amphibolite-facies metamorphism associated with granitic magmatism interpreted from TAMBOURAH (Van Kranendonk, 2003) and WHITE SPRINGS (Smithies, in prep.) <3240 – >2945 Deformation of granite/gneiss and greenstone sequences; 110–160° trending fabric. Age inferred from relationships on TAMBOURAH (Van Kranendonk, 2003) <3060 – 2945 Amphibolite-facies metamorphism, including generation of the Cockeraga Leucogranite from a c. 3060 Ma source region c. 2945 – 2930 Voluminous granitic magmatism in the Yule Granitoid Complex, including intrusion of the Powdar Monzogranite c. 2945 – 2930 Development of northeast-trending foliation throughout the Yule Granitoid Complex c. 2930 – 2775 Erosion c. 2775 – 2630 Deposition of volcanic and sedimentary rocks of the Fortescue Group 2770 and younger Dip-slip faulting along major northeasterly trending faults c. 2600 – 2500 Deposition of lower Hamersley Group <2600 Intrusion of dolerite dykes; east-northeast faulting

4 GSWA Explanatory Notes Geology of the Hooley 1:100 000 sheet

Table 2. Precise U–Pb zircon geochronology (SHRIMP(a)) relevant to units on HOOLEY

Age (Ma) Lithology Formation/Group/Complex Sample Reference

2561 ± 8 Crystal-rich tuff Wittenoom Formation, Hamersley Group 120044 Trendall et al. (1998) 2597 ± 5 Mount Newman Member Marra Mamba Iron Formation, Hamersley Group 120046 Trendall et al. (1998) 2763 ± 13 Lapilli tuff Mount Roe Basalt, Fortescue Group 94792 Arndt et al. (1991) 2775 ± 10 Felsic volcanic rock Mount Roe Basalt, Fortescue Group 86738 Arndt et al. (1991) 2715 ± 6 Pillingini Tuff Tumbiana Formation, Fortescue Group 94775 Arndt et al. (1991) 2719 ± 6 Volcaniclastic sandstone Tumbiana Formation, Fortescue Group 168935 Nelson (2001) 2717 ± 2 Dacite Maddina Formation, Fortescue Group 144993 Nelson (1998) 2684 ± 6 Tuffaceous sandstone Jeerinah Formation, Fortescue Group 94776 Arndt et al. (1991) 2690 ± 16 Tuffaceous sandstone Jeerinah Formation, Fortescue Group 103225 Arndt et al. (1991) 2935 ± 3 Powdar Monzogranite Yule Granitoid Complex 142937 Nelson (2000) 2945 ± 5 Mungaroona Granodiorite Yule Granitoid Complex 142938 Nelson (2000) <3068 ± 22 Cockeraga Leucogranite Yule Granitoid Complex 169014 Nelson (2002) <3066 ± 4 Cockeraga Leucogranite Yule Granitoid Complex 169016 Nelson (2002)

NOTE: (a) Sensitive high-resolution ion microprobe

granite–greenstone terranes. The supergroup has been Leucogranite dominate outcrop. These granitic rocks described in detail by Hickman (1983), Blake (1993), and contain gneissic xenoliths, and locally abundant Thorne and Trendall (2001). The lowest stratigraphic greenstone xenoliths, interpreted as derived from the component is the Fortescue Group that was deposited greenstone pendant into which the leucogranite has between c. 2775 and 2630 Ma (Arndt et al., 1991; Nelson, intruded. The Cockeraga Leucogranite has a maximum 1997; Wingate, 1999: Thorne and Trendall, 2001; Table 2). age of c. 3065 Ma (Nelson, 2002), but is likely to be younger than this (Smithies, in prep.). A hornblende– According to Arndt et al. (2001), Fortescue Group biotite tonalite forms a discrete, approximately 10 km- volcanism is the result of lithospheric melting during long, body close to the southern unconformity with three successive phases of mantle plume activity. Thorne the Fortescue Group. This tonalite is intruded by and Trendall (2001), however, cited the lithological the Powdar Monzogranite, but contact relationships with diversity of the group and the long duration of volcanism the Cockeraga Leucogranite, which is exposed to the (around 140 million years) as evidence against this southeast, could not be determined. The tonalite hypothesis, and described the tectonic setting of the is petrographically and geochemically similar — Fortescue Group in terms of a single, protracted rifting unpublished geochemical data from Geological Survey event. Blake (1993) also suggested that the lower parts of of Western Australia (GSWA) and Geoscience Australia the Mount Bruce Supergroup record a period of late (GA) — to the Mungaroona Granodiorite, which Archaean west-northwest crustal extension, followed by is exposed on SATIRIST (Smithies and Farrell, 2000) south-southwest rifting of the southern margin of the and which has an age of c. 2940 Ma (Nelson, 2000). Pilbara Craton. Greenstones on HOOLEY are restricted to xenoliths in, and roof-pendants on, granitic rocks of the Yule Granitoid Archaean rocks Complex. Due to sparse outcrop and lack of continuity with formally recognized stratigraphic components, these The Archaean geology and geological history of HOOLEY greenstones cannot be confidently assigned to groups or is summarized on Interpreted bedrock geology (see formations within the Pilbara Supergroup. The 12 km- main map) and in Table 1. Geochronological data relevant long, east-trending Punduna greenstone pendant forms the to HOOLEY and surrounding areas is presented in Table 2. largest outcrop of greenstone. The consistent west- northwest strike of the stratigraphy suggests that this Approximately 70% of the EPGGT in the northeastern pendant can be correlated to the Cheearra greenstone belt part of HOOLEY is granitic rock, all of which belongs to in the southern part of SATIRIST (Smithies and Farrell, the Yule Granitoid Complex. Seriate-textured to 2000). The rocks of the pendant are metamorphosed to K-feldspar-porphyritic monzogranites of the c. 2935 Ma amphibolite facies and are largely derived from mafic (Nelson, 2000) Powdar Monzogranite (Smithies and volcanic rocks, although interleaved rocks of sedimentary Farrell, 2000) dominate outcrop, particularly to the west and ultramafic protolith are locally abundant. Rocks of of the large area of greenstones referred to here as the sedimentary or ultramafic protolith form local, discrete Punduna greenstone pendant. North of the Punduna mappable units. Relict olivine-spinifex textures indicate greenstone pendant, the Powdar Monzogranite includes that some of the ultramafic rocks are metamorphosed large xenoliths, up to 2 km long, of gneissic monzogranite. komatiites. These belong to the Cheearra Monzogranite, which forms a major component of the Yule Granitoid Complex on The Neoarchaean to Palaeoproterozoic Hamersley SATIRIST. To the east and south of the Punduna greenstone Basin contains a volcanic and sedimentary succession — pendant, schlieric biotite granitic rocks of the Cockeraga the Mount Bruce Supergroup — that is up to 10 km thick

5 Smithies and covers approximately 100 000 km2 (Trendall, 1990). Mafic rocks (Aba, Abal, Abag, Abas, This succession is subdivided into three lithostratigraphic Abu, Abuq) groups — Fortescue, Hamersley, and Turee Creek. Only the lower two groups are preserved on HOOLEY, with the Most of the unassigned greenstone units on HOOLEY Fortescue Group dominating outcrop. comprise metamorphosed mafic rock. The dominant rock type is fine- to medium-grained, massive to strongly On HOOLEY, rocks of the c. 2775–2630 Ma Fortescue foliated amphibolite-facies mafic rock (Aba). This Group (Arndt et al., 1991; Nelson et al., 1999; Wingate, comprises a typically granoblastic assemblage of 1999; Thorne and Trendall, 2001), and the lowest part of hornblende, plagioclase, and quartz, and locally the Hamersley Group typically dip to the south or clinopyroxene, or less commonly orthopyroxene. The southwest at less than 10°, and are only very weakly rocks are typically melanocratic to mesocratic. Leucocratic metamorphosed. An unconformity is well developed amphibolite (Abal), with less than 20% hornblende, is between the Fortescue Group and the underlying granite– mapped separately along the southern part of the Punduna greenstone terrane. On the map area, all recognized greenstone pendant. Similar rock is well exposed in the formations of the Fortescue Group are preserved; however, foothills of the Mungaroona Range (e.g. MGA 648000E regional topographic variations at the time the group 7606800N). was deposited have resulted in locally incomplete development of the lower units. The Mount Roe Basalt Within the Punduna greenstone pendant, medium- is only developed in the northwest of the sheet. Elsewhere grained amphibolite locally contains abundant layers, on HOOLEY the Hardey and Kylena Formations form veins, and irregular patches of tonalite (Abag; e.g. MGA the base of the Fortescue Group. In the southwest corner, 645000E 7615400N). Where tonalite is abundant the rocks the contact between the Jeerinah Formation and the resemble components of the heterogeneous Cockeraga overlying Marra Mamba Iron Formation marks the Leucogranite (AgYco). boundary between the Fortescue and Hamersley Groups (Thorne and Trendall, 2001). There is no evidence on Amphibolite is partially retrogressed, with variable the map area of an unconformity between these alteration of hornblende to actinolite and chlorite, and of groups. Rather, carbonaceous mudstones and siltstones plagioclase to sericite and epidote. Where metamorphic of the Jeerinah Formation pass conformably upwards retrogression is associated with deformation, the rocks are into the ferruginous mudstones of the Marra Mamba transitional to mafic schist and comprise interleaved Iron Formation. The Wittenoom Formation that amphibolite and actinolite schist (Abas). conformably overlies the Marra Mamba Iron Formation is not exposed on HOOLEY, but is interpreted to underlie Mafic and ultramafic rocks that are stratigraphically Cainozoic calcrete deposits in the far southwest of the interleaved at metre scale (Abu) outcrop west of the sheet area. Punduna greenstone pendant (MGA 634000E 7621700N), and form the southern extension of the Cheearra greenstone belt exposed on SATIRIST. The mafic component of these rocks can be either amphibolite or actinolite– Unassigned greenstone units chlorite schist. The ultramafic component is typically Ultramafic rocks (Au, Auk, Aur) tremolite schist. A similar unit dominates the northern half of the Punduna greenstone pendant, where the mafic and Outcrops of metamorphosed ultramafic rock that are ultramafic rocks are also interleaved with quartz– weathered or strongly deformed have mainly been mapped muscovite schist and quartzite (Abuq). as undivided ultramafic rock (Au). In areas of better exposure, the ultramafic rocks have been subdivided into metamorphosed peridotitic komatiite (Auk) and tremolite- Sedimentary rocks (Asq, Asqn) rich schist (Aur). Quartz–muscovite schist and quartzite (Asq), after Undivided ultramafic rock (Au) includes serpentine subarkose, outcrop to the west of the Punduna greenstone schist, tremolite schist, and talc–tremolite–chlorite schist. pendant (at MGA 635500E 7621700N), in association with These are exposed in the Punduna greenstone pendant and interleaved mafic and ultramafic rocks (Abu) of the also form isolated xenoliths within rocks of the Yule Cheearra greenstone belt. The quartz–muscovite schist and Granitoid Complex. quartzite unit, which is an important component of the Cheearra greenstone belt on SATIRIST (Smithies and Farrell, Serpentine–talc–tremolite rock (Auk) locally preserves 2000), contains between 70 and 95% quartz. Less quartz- olivine-spinifex textures and is metamorphosed peridotitic rich components of this unit are locally well layered, with komatiite. It forms a prominent outcrop along the southern layering defined by feldspar-rich layers, a prominent margin of the Punduna greenstone pendant, and also forms schistosity produced by alignment of muscovite, or a minor xenoliths within rocks of the Yule Granitoid combination of both. The more quartz-rich rocks are Complex (e.g. MGA 642000E 7605500N). typically massive and comprise a granoblastic assemblage of quartz–plagioclase (now epidote and sericite), and rare Tremolite-rich schist (Aur) is the most abundant microcline and clinopyroxene. Actinolite is a late- ultramafic rock type. It is typically fine grained and well crystallizing acicular mineral. Within the Punduna foliated, and comprises acicular or fibrous tremolite, with greenstone pendant quartzite is interleaved with locally subordinate amounts of chlorite, talc, and fine-grained layered quartz and quartz–feldspar–amphibole paragneiss opaque minerals. (Asqn; e.g. MGA 643000E 7620500N, and MGA 647000E

6 GSWA Explanatory Notes Geology of the Hooley 1:100 000 sheet

7613500N). Layering is defined by 10 cm- to 1 m-thick to kilometre-scale blocks, and are sourced from metasedi- layers rich in amphibole, interpreted to be original mentary, granite, and mafic to ultramafic igneous protolith. sedimentary bedding. Schlieren typically represent variably disaggregated xenolithic material, which in some cases is demonstrably Quartz–muscovite schist and quartzite (Asq) is also of local origin. In thicker leucogranite units, schlieren are faulted against rocks of the Fortescue Group, in the typically strongly attenuated, but become more common northwestern corner of HOOLEY (e.g. MGA 607000E and angular towards contacts with greenstone country-rock 7612000N). Here, metamorphic grade is notably lower or xenoliths. The greenstone country-rock or xenoliths are than in the Punduna greenstone pendant. The unit also themselves metamorphosed to at least lower amphibolite includes interbeds of fine-grained tuff as well as pebble facies, and become increasingly invaded (net-veined), or conglomerate (Van Kranendonk, M. J., 2002, written swamped and disaggregated by leucogranite, close to comm.). It is not clear whether this outcrop belongs to the leucogranite sheets. Biotite is the predominant mafic Pilbara Supergroup or to the Fortescue Group. mineral in schlieren, but is accompanied by hornblende where the leucogranite has intruded mafic xenoliths. A flow foliation is particularly well defined in the schlieren- Yule Granitoid Complex rich rocks. It locally wraps around xenoliths and shows irregular ‘swirls’ that do not conform to regional structural Cheearra Monzogranite (AgYchn) trends. Outcrops of gneissic monzogranite to granodiorite (AgYchn) in the far northeast of HOOLEY (MGA 645500E Hornblende–biotite tonalite (AgYt) 7621000N) are interpreted as xenoliths in both the seriate- textured Powdar Monzogranite (AgYpos) and the Coarse-grained and massive, this hornblende–biotite Cockeraga Leucogranite (AgYco). The gneissic unit tonalite (AgYt) forms a discrete, approximately 10 km-long includes hornblende-rich granodioritic and tonalitic body, to the south of Punduna Pool (e.g. MGA 645000E varieties. It is mineralogically identical to, and texturally 7608000N). This mesocratic rock has locally well transitional from, a moderately to strongly foliated developed 10 cm to metre-scale layering that parallels the monzogranite (AgYchm) that outcrops to the north on strike of greenstone units within the Punduna greenstone SATIRIST (Smithies and Farrell, 2000). Mesocratic and pendant. The layering is defined by variations in the leucocratic bands are locally well developed with combined abundance of mafic minerals (Fig. 3) and almost stromatic banding in some outcrops. certainly reflects emplacement of at least parts of the tonalite body via sheeted intrusion. The tonalite is undeformed, and so is younger than the greenstones and Cockeraga Leucogranite (AgYco, gneissic rocks, but older than the c. 2935 Ma (Nelson, AgYcor, AgYcorx) 2000) porphyritic monzogranite of the Powdar Monzogranite (AgYpos), which intrudes it. Mineralogic- The Cockeraga Leucogranite outcrops sporadically near ally, the tonalite differs from the Mungaroona Granodiorite the northeastern boundary of HOOLEY. The unit comprises (AgYmux) only in containing a relatively higher proportion leucocratic biotite(–hornblende) tonalite or granodiorite, of plagioclase; however, the two rocks are geochemically with subordinate monzogranite (AgYco). These rocks very similar (GSWA–GA, unpublished data). Accordingly, commonly show a distinctive, well developed, schlieric it is speculated that the tonalite is similar in age to the banding (AgYcor), and locally also contain abundant c. 2945 Ma Mungaroona Granodiorite (Nelson, 2000). xenoliths of greenstone and gneiss (AgYcorx). The precise age of the leucogranite has not been determined. The youngest population of zircons from two samples collected Mungaroona Granodiorite (AgYmux) on WHITE SPRINGS (GSWA 169014 and 169016, both at MGA 675720E 7595740N) provided a U–Pb sensitive A small outcrop of the Mungaroona Granodiorite, locally high-resolution ion microprobe (SHRIMP) age of containing abundant greenstone xenoliths and rafts c. 3065 Ma (Nelson, 2002). While this may be the (AgYmux), in the northwest of HOOLEY (MGA 611600E crystallization age of the rocks, geochemical data 7622100N), is fault-bounded against rocks of the Fortescue (GSWA–GA unpublished data) suggests that these rocks Group. The rock is typically a medium- to coarse-grained are the result of disequilibrium melting, and might still and mostly equigranular hornblende–(biotite) granodiorite contain abundant restite. Accordingly, the preferred or (rarely) biotite monzogranite. A sample of Mungaroona interpretation is that the age obtained (c. 3065 Ma) Granodiorite from SATIRIST was dated at c. 2945 Ma represents the minimum age of the source and the (Nelson, 2000) maximum age of the leucogranite, which may be as young as c. 2940 Ma, the age of voluminous granite magmatism in the region. Powdar Monzogranite (AgYpop, AgYpos) The Cockeraga Leucogranite ranges from medium- to coarse-grained tonalite or granodiorite. It is composition- On SATIRIST, the Powdar Monzogranite (AgYpo) includes ally and texturally highly variable at outcrop scale, four distinct mineralogical and textural varieties, but on comprising an accumulation of individual sheets and HOOLEY only a porphyritic monzogranite (AgYpop) and veins, readily identified by abrupt changes in grain size seriate-textured monzogranite (AgYpos) are exposed, and mineralogy. Inclusions range from pea-sized clots up differing only in the abundance of K-feldspar phenocrysts.

7 Smithies

RHS246 29.05.03

Figure 3. Layering in hornblende–biotite tonalite defined by variations in the relative proportions of hornblende and plagioclase (typically on a 10–50 cm scale). Mafic xenoliths (left of lens cap) are rounded cognate inclusions of diorite and gabbro

These rocks are typically leucocratic with biotite, the sole and particularly to larger bodies of tonalitic to mafic silicate mineral (now mostly chlorite), comprising granodioritic composition. Metamorphic temperatures in less than 5% of the rock. The rocks are commonly massive the northwestern part of the EPGGT (e.g. SATIRIST), and to weakly deformed, but locally have a strong foliation in the Mallina Basin region, peaked at c. 2950 Ma, defined by flow alignment of K-feldspar phenocrysts. A approximately coincident with voluminous magmatism sample of the Powdar Monzogranite (GSWA 142937) (Smithies and Farrell, 2000). from SATIRIST was dated at c. 2935 Ma (Nelson, 2000). All greenstone assemblages (in xenoliths and roof pendants) on HOOLEY have been metamorphosed to at least Unassigned granitoid (AgY ) lower-amphibolite facies. Although the mineralogy of most rocks reflects extensive retrogression, preservation Surrounded by outcrop of the lower parts of the Fortescue of the peak metamorphic assemblage, hornblende– Group, this strongly weathered granitic rock is of plagioclase(–clinopyroxene), is widespread. Smithies and uncertain age and relationship to other granitic rocks of Farrell (2000) noted that on SATIRIST the metamorphic the Yule Granitoid Complex (AgY; e.g. MGA 629000E mineral assemblages in the pre-metamorphic component 7603000N). It is interpreted to have formed topographic of the Cheearra Monzogranite (AgYch), and in the highs at the time of early Fortescue Group deposition. Cheearra greenstone belt, show a progressive southerly increase in metamorphic grade. It appears that this trend continues onto HOOLEY as evidenced by the prevalence of Metamorphism amphibolite-facies mineral assemblages in rocks of the Punduna greenstone pendant. It is not clear if this Most rocks of the EPGGT are metamorphosed to low- to metamorphic trend is related to local intrusion of granitic middle-greenschist facies, characterized by the presence rocks or is more regional in nature, reflecting a northerly of chlorite–actinolite–albite(–epidote) in mafic rocks, decrease in structural depth. and albite–biotite(–white mica – chlorite) in pelitic metasedimentary rocks. Amphibolite-facies assemblages Furthermore, structures defined by amphibolite-facies are locally developed close to contacts with granitic rocks, assemblages of the Western Shaw greenstone belt on

8 GSWA Explanatory Notes Geology of the Hooley 1:100 000 sheet

TAMBOURAH can be related to an earlier c. 3240 Ma phase includes interstitial chlorite and epidote (after mafic phases of deformation (Wijbrams and McDougall, 1987; Van and glass). The glomeroporphyritic rocks differ from the Kranendonk, 2003). Hence, the metamorphic history of vesicular variety only in that they contain abundant the EPGGT in the HOOLEY region may have been long and aggregates of plagioclase up to 2 cm in size. Both the complex. vesicular and glomeroporphyritic basalt are locally pillowed.

Structure Hardey Formation (AFh, AFhu) All phases of the Yule Granitoid Complex on HOOLEY Regionally, the Hardey Formation (AFh) includes a wide show a weak east-northeasterly trending foliation (S3), and range of sedimentary and volcanic rocks deposited in except for foliations developed adjacent to late faults, this various alluvial (including fan), fluvial, lacustrine, deltaic, is the only deformational fabric developed in the c. 2945 and shoreline environments (Thorne and Trendall, 2001). to 2930 Ma granitic rocks that dominate the complex. It overlies the Mount Roe Basalt in northwestern HOOLEY, but in the central-northern part of the sheet it unconform- In the greenstones, this late east-northeasterly trending ably overlies the EPGGT. This unit was originally referred foliation overprints a strongly developed foliation. In the to as the Hardey Sandstone, but was later renamed by Punduna greenstone pendant, the greenstones are folded Thorne et al. (1991). On HOOLEY the Hardey Formation with steep east-southeasterly trending axial planes (Fig. 4), comprises medium- to coarse-grained, poorly sorted with a strongly developed axial-planar foliation (S ). The 2 subarkose, with locally developed conglomerate, well- age of this early foliation is unknown, but a similarly laminated siltstone, shale, and felsic tuff. It is, however, oriented fabric developed in greenstone xenoliths in the dominated by a sequence of poorly sorted, medium- to eastern part of WHITE SPRINGS (Fig. 4) overprints a fabric coarse-grained, volcanolithic sandstone, interbedded with (S ) that Van Kranendonk (2003) related to a c. 3240 Ma 1 well-laminated siltstone, fine-grained tuffaceous phase of deformation. On this evidence, the age of the sedimentary rock, and conglomerate (AFhu). east-southeast fabric is constrained between c. 3240 and 2945 Ma, as there is no other known phase of deformation during that period in the EPGGT (Van Kranendonk et al., Kylena Formation (AFk, AFkbi, AFkh) 2002). The Kylena Formation (AFk), previously the Kylena Basalt (Kojan and Hickman, 1998), conformably or disconform- ably overlies the Hardey Formation in the northwestern Hamersley Basin part of HOOLEY. Farther to the southeast it forms the basal unit of the Fortescue Group, in direct contact with Fortescue Group basement rocks of the EPGGT. The unit typically The Fortescue Group is a c. 2775–2630 Ma (see Table 2; comprises flows of massive to amygdaloidal basalt and Arndt et al., 1991; Nelson et al., 1999; Wingate, 1999; basaltic andesite, and is known regionally to contain minor Thorne and Trendall, 2001) succession of dominantly intercalations of high-Mg basalt, dacite, and rhyolite basaltic rocks that extends across much of the Pilbara (Kojan and Hickman, 1998). Layers in which basaltic Craton. An angular unconformity defines its contact with andesite, with minor basalt and andesite (AFkbi) are the granite–greenstone terrane. Polymictic conglomerate dominant were mapped separately. Basalt and basaltic containing subrounded clasts derived from the underlying volcaniclastic rocks, including breccia, locally contain granite–greenstone terrane, and a medium- to coarse- sericite and pyrophyllite alteration along epithermal veins grained, poorly sorted sandstone, locally mark the base of and bedding planes (AFkh). This hydrothermal alteration produces bleached zones that are readily identifiable the group on HOOLEY. These units are generally too thin and irregular to be represented at 1:100 000 scale. Rocks on aerial photography (e.g. MGA 646000E 7601300N) of the Fortescue Group typically dip shallowly southward and is interpreted as syn- to late-volcanic, epithermal-style with a resultant gradual southerly progression to higher alteration. stratigraphic levels. All recognized formations of the Fortescue Group are preserved. Tumbiana Formation (AFt, AFtsv, AFtc, AFtsvs, AFtsvb)

Mount Roe Basalt (AFr) On HOOLEY, the Tumbiana Formation (AFt) is a thin The Mount Roe Basalt (AFr) forms the basal unit of the (<200 m) unit comprising mainly coastal and nearshore Fortescue Group. It comprises both subaerial and shelf facies, clastic and volcaniclastic rocks. It includes a subaqueous lava facies, but no reliable indicators were distinctive stromatolitic carbonate horizon and a minor mafic lava component (Thorne and Trendall, 2001) that observed on HOOLEY to establish the local environment of deposition. becomes a locally volumetrically significant component on HOOLEY, and further east on WHITE SPRINGS. The contact This unit is only preserved in the far northwest corner between the Tumbiana Formation and Kylena Formation of the sheet area. Much of the Mount Roe Basalt is has been regarded as a conformity, as it appears on composed of either massive, vesicular or glomero- HOOLEY; however, Hickman (in prep.) documented a porphyritic basalt. The vesicular basalt contains rare, locally unconformable relationship between these two squat, subhedral phenocrysts of plagioclase and units on , in the West Pilbara Granite– clinopyroxene in a plagioclase-rich groundmass that also Greenstone Terrane.

9

Smithies 119' 00° 00° 119' 21° 30' 19.05.03 22° 00' extension Western Shaw greenstone belt Areas of abundant greenstone xenoliths and roof pendants Fault Trend of main foliations Fold hinge 2 3 1 S S S Dyke Supergroup Greenstone Granitic rock Mount Bruce xenolith field Mount Gratwick WHITE

SPRINGS 118° 30' 118° HOOLEY Punduna Cheearra greenstone pendant greenstone belt and adjacent 1:100 000 map areas. Also shown are major greenstone outcrops, and in boxes, areas of abundant and adjacent 1:100 OOLEY greenstone xenoliths and pendants

10 km 118° 00' 118° SATIRIST HOOLEY RHS243 Figure 4.Figure Structural overview of H

10 GSWA Explanatory Notes Geology of the Hooley 1:100 000 sheet

Four subdivisions of this formation are recognized on According to Thorne and Trendall (2001), the Woodiana HOOLEY. The dominant and locally basal package Member reflects deposition in a nearshore shelf comprises metre- to tens of metre-scale interbeds of environment, whereas the middle and upper parts of the volcaniclastic sandstone, carbonate-rich tuff, and Jeerinah Formation reflect deposition within an offshore volcaniclastic mudstone and siltstone (AFtsv). This lower shelf environment. On HOOLEY, rocks characteristic of the package also includes distinct layers of dark-grey, latter facies include variegated, light-coloured mudstone siliceous stromatolitic dolomite and limestone. Where and siltstone (AFjsl), and an overlying unit comprising these carbonate units are abundant or dominant, they were carbonaceous mudstone and siltstone, chert, and local mapped as the Meentheena Carbonate Member (AFtc). dolomite beds (AFjslg). Within this carbonaceous mudstone and siltstone unit, dolomite and dolomitic shale The upper part of the Tumbiana Formation on HOOLEY (AFjkd) form local mappable layers (e.g. MGA 607800E comprises fine- to coarse-grained volcaniclastic sandstone, 7577000N). tuff, and fine-to medium-grained clastic sedimentary rock (AFtsvs), with rare carbonate-rich interbeds. This unit appears to combine parts or all of the upper units, as Hamersley Group mapped to the northwest on COOYA POOYA (Hickman, in prep.). These include sandstone and siltstone (AFtss), Marra Mamba Iron Formation (AHm) tuff, and tuffaceous siltstone, commonly with accretionary Outcrop of the Hamersley Group on HOOLEY is restricted lapilli (AFtt), and arenaceous siltstone and tuff (AFtsl). to the far southwest corner of the sheet. The group typically comprises poorly outcropping interbeds of chert, In the area around Wonga Well, in the central part of banded iron-formation, mudstone, and siltstone of the HOOLEY, the volcaniclastic sandstone, tuff, and clastic Marra Mamba Iron Formation (AHm). No evidence is sedimentary rock unit (AFtsvs) contains abundant preserved of an unconformity between this unit and the basalt sheets and dykes (AFtsvb). Contacts between underlying Jeerinah Formation, although there are basalt and sedimentary rocks are locally peperitic, significant changes from north to south in the thickness evidence of synchronous clastic sedimentation and mafic of units within the latter formation (particularly in AFjslg). volcanism.

Maddina Formation (AFm, AFmk, AFmx) Structure and metamorphism The Maddina Formation (AFm) outcrops over much of the For both the Fortescue and Hamersley Groups, bedding southwestern quarter of HOOLEY. Regionally, the formation surfaces typically dip at a shallow angle, predominantly consists mainly of basalt flows, pillow lavas, and fine- to southwards. The rocks show gentle folding (Fig. 4) and coarse-grained mafic volcaniclastic rocks. Subordinate broad domal features are locally present (MGA 604500E dacite, rhyolite, and non-volcanic sedimentary rock, 7612000N). North-northeasterly trending faults show a including stromatolitic carbonate and quartz sandstone are dip-slip component that has locally juxtaposed quartz– present (Thorne and Trendall, 2001). muscovite schist and quartzite (Asq), in the northwestern part of HOOLEY, against rocks of the Tumbiana Formation On HOOLEY, the Maddina Formation typically consists (MGA 606600E 7611000N), and has uplifted a wedge of of massive, vesicular, and amydaloidal basalt, and basaltic Mount Roe Basalt. These faults typically do not affect the AFm andesite ( ). Included is a distinct layer of mafic Maddina Formation, and it is likely that fault movement volcanicalstic sandstone, mudstone, chert, and dolomite pre-dates deposition of that formation. called the Kuruna Member (AFmk), which Thorne and Trendall (2001) interpreted to have accumulated in a low- Northeast-trending faults are a common and significant energy shallow coastal setting. In the southeast corner of feature throughout HOOLEY, and for many of these the the sheet, the Maddina Formation includes extensive latest phase of movement probably post-dated deposition deposits of basaltic volcaniclastic breccia (AFmx) of the Fortescue Group. These faults contain evidence of consisting of angular basalt fragments, up to 30 cm across, both strike-slip and dip-slip displacements; however, only with a chlorite- and carbonate-rich mafic matrix. the latter appears to typify displacement after deposition of the Fortescue Group.

Jeerinah Formation (AFjslg, AFjo, AFjsl, AFjkd) The rocks of the Fortescue and Hamersley Groups Outcrop of the Jeerinah Formation is confined to the have been subject to low-grade metamorphism, character- southwest corner of HOOLEY. Regionally, this formation ized in mafic rocks by an assemblage containing chlorite includes argillite, sandstone, dolomite, chert, and a variety and epidote. of volcanic rocks including basalt flows, as well as mafic to felsic volcaniclastic rocks (Thorne and Trendall, 2001). Dolerite dykes (d) On HOOLEY the basal unit of the formation — the Woodiana Member (AFjo) — appears to conformably Dolerite dykes (d), of undetermined age are recognized overly the Maddina Formation. It comprises quartz-rich in the southern and northern parts of HOOLEY. They sandstone interbedded with subordinate chert, chert typically trend either east-northeast or north, and are breccia, mudstone, and volcanogenic lithic sandstone, and associated with a late phase of faulting (e.g. MGA is locally well preserved (e.g. MGA 606000E 7584000N). 647500E 7577500N).

11 Smithies

the EPGGT, particularly adjacent to the present channel Cainozoic deposits of Pilbaddy Creek. Alluvial calcrete (Czak) is exposed along the southwestern bank of the Fortescue River, in the Residual deposits (Czru, Czrk, far southwest corner of the sheet, where it is interpreted Czrfb) to overlie the Wittenoom Formation of the Hamersley Group. Massive, grey, siliceous caprock over ultramafic rock (Czru) is associated with altered outcrop of tremolite-rich schist (Aur) in the northern part of HOOLEY (MGA Quaternary colluvium and 643000E 7619400N). sheetwash deposits (Qc, Qw) Massive, nodular, and cavernous limestone of residual origin (Czrk) in the far northeast corner of the map area Colluvium, consisting of sand, silt, and gravel, is locally is developed over rocks of the EPGGT. The deposit is derived from elevated outcrops and deposited on outwash more extensively developed in the southwestern part of the fans, and talus slopes (Qc). In more distal regions, sheet, mainly over mafic rocks of the Maddina Formation. sheetwash deposits (Qw) of silt, sand, and pebbles are deposited on outwash fans. Locally reworked by wind Ferruginous caprock (Czrfb), developed over basalt, action, sand deposits have generally been stabilized by forms small exposures in the northwestern part of HOOLEY extensive grass and shrub cover. (MGA 615000E 7622000N), is more extensively developed to the north, on SATIRIST. It forms laterite platforms that are slightly elevated compared to adjacent colluvial Quaternary alluvial deposits (Qaa, deposits developed over basaltic rocks of the Fortescue Group. Qao, Qab) Present-day drainage channels contain alluvial clay, silt, and sand in channels on floodplains, or sand and gravel Colluvium (Czc, Czcb) in rivers and creeks (Qaa). Alluvial clay, silt, and sand form overbank deposits on floodplains (Qao) and locally Dissected and consolidated colluvium (Czc) forms include gilgai (Qab). outwash fans, flanking elevated outcrop in the northeastern and southwestern parts of the sheet. These deposits consist of clay- or silica-cemented, poorly stratified silt, sand, and gravel, typically with a high proportion of mafic (chloritic) Economic geology detritus, except where derived from granitic rocks. In the southwest part of HOOLEY, a gilgai surface has locally There are no known gold occurrences on HOOLEY, nor are developed over colluvial deposits (Czcb). Gilgai is a clay- there any currently working mines or prospects. In the past rich silt or sand deposit characterized by the development the late (c. 2935 Ma) granitic rocks of the Yule Granitoid of numerous cracks and sinkholes. The clay expands and Complex (AgYpos) have been prospected for pegmatite- contracts according to water content, and in dry conditions hosted beryl (MGA 636900E 7612300N); alluvial produces an irregular ‘crabhole’ surface. corundum has been found in Corung Creek (MGA 647500E 7609810N; Kriewaldt and Ryan, 1967), and iron- rich regolith deposits have been investigated over rocks Alluvial deposits (Czaf, Czag, of the Marra Mamba Iron Formation, in the southwest of HOOLEY (MGA 604200E 7575800N; Ruddock, 1999). For Czak ) a detailed description of the mineral occurrences and exploration potential of the EPGGT see Ruddock (1999). Alluvial deposits dissected by recent drainage are a minor component on HOOLEY. Pisolitic limonite deposits (Czaf ) form two small mesas 1–2 km to the southeast of Hooley Homestead. Alluvial gravel (Czag) is only in the northeastern part of the map, where it overlies rocks of

12 GSWA Explanatory Notes Geology of the Hooley 1:100 000 sheet

References

ARNDT, N. T., NELSON, D. R., COMPSTON, W., TRENDALL, KRIEWALDT, M., and RYAN, G. R., 1967, Pyramid, W.A.: Western A. F., and THORNE, A. M., 1991, The age of the Fortescue Australia Geological Survey, 1:250 000 Geological Series Group, Hamersley Basin, Western Australia, from ion microprobe Explanatory Notes, 39p. zircon U–Pb results: Australian Journal of Earth Sciences, v. 38, NELSON, D. R., 1997, Compilation of SHRIMP U–Pb zircon p. 261–281. geochronology data, 1996: Western Australia Geological Survey, ARNDT, N., BRUZAK, G., and REICHMANN, T., 2001, The oldest Record 1997/2, 189p. contintental and oceanic plateaus: Geochemistry of basalts and NELSON, D. R., 1998, Compilation of SHRIMP U–Pb zircon komatiites of the Pilbara Craton, Australia: Geological Society of geochronology data, 1997: Western Australia Geological Survey, America, Special Paper 352, p. 359–387. Record 1998/2, 242p. BARLEY, M. E., 1997, The Pilbara Craton, in Greenstone belts edited NELSON, D. R., 2000, Compilation of geochronology data, 1999: by M. J. DE WIT and L. D. ASHWALL: Oxford University Press, Western Australia Geological Survey, Record 2000/2, 205p. p. 657–664. NELSON, D. R., 2001, Compilation of geochronology data, 2000: BEARD, J. S., 1975, The vegetation of the Pilbara area: University of Western Australia Geological Survey, Record 2001/2, 205p. Western Australia, 1:100 000 Vegetation Series Map and Explanatory Notes, University of Western Australia Press, 120p. NELSON, D. R., 2002, Compilation of geochronology data, 2001: Western Australia Geological Survey, Record 2002/2, 282p. BLAKE, T. S., 1993, Late Archaean crustal extension, sedimentary basin formation, flood basalt volcanism, and continental rifting: the NELSON, D. R., TRENDALL, A. F., and ALTERMANN, W., 1999, Nullagine and Mount Jope supersequences, Western Australia: Chronological correlations between the Pilbara and Kaapvaal Precambrian Research, v. 60, p. 185–242. Cratons: Precambrian Research, v. 97, p. 165-189. BUICK, R., THORNETT, J. R., McNAUGHTON, N. J., SMITH, J. B., RUDDOCK, I., 1999, Mineral occurrences and exploration potential of BARLEY, M. E., and SAVAGE, M., 1995, Record of emergent the west Pilbara: Western Australia Geological Survey, Report 70, continental crust ~3.5 billion years ago in the Pilbara Craton of 63p. Australia: Nature, v. 375, p. 574–577. SMITHIES, R. H., in prep., Geology of the White Springs 1:100 000 CAMPANA, B., HUGHES, F. E., BURNS, W. G., WHITCHER, I. G., sheet: Western Australia Geological Survey, 1:100 000 Geological and MUCENIEKAS, E., 1964, Discovery of the Hamersley iron Series Explanatory Notes. deposits (Duck Creek – Mt Pyrton – Mt Turner areas): Australasian SMITHIES, R. H., and FARRELL, T. R., 2000, Geology of the Satirist Institute of Mining and Metallurgy, Proceedings, v. 210, p. 1–30. 1:100 000 sheet: Western Australia Geological Survey, 1:100 000 CHAMPION, D. C., and SMITHIES, R. H., 1998, Archaean granites Geological Series Explanatory Notes, 42p. of the Yilgarn and Pilbara Cratons, in Granites, island arcs, the SMITHIES, R. H., HICKMAN, A. H., and NELSON, D. R., 1999, mantle and ore deposits, The Bruce Chappell Symposium New constraints on the evolution of the Mallina Basin, and their Abstracts: Australian Geological Survey Organisation, Record bearing on relationships between the contrasting eastern and western 1998/33, p. 24–25. granite–greenstone terranes of the Archaean Pilbara Craton, Western CHAMPION, D. C., and SMITHIES, R. H., 2000, The geochemistry Australia: Precambrian Research, v. 94, p. 11–28. of the Yule Granitoid Complex, East Pilbara Granite–Greenstone THORNE, A. M., and TRENDALL, A. F., 2001, Geology of the Terrane; evidence for early felsic crust: Western Australia Geological Fortescue Group, Pilbara Craton, Western Australia: Western Survey, Annual Review 1999–2000, p. 42–48. Australia Geological Survey, Bulletin 144, 249p. HICKMAN, A. H., 1983, Geology of the Pilbara Block and its environs: THORNE, A. M., TYLER, I. M., and HUNTER, W. M., 1991, Western Australia Geological Survey, Bulletin 127, 268p. Turee Creek, W.A. (2nd edition): Western Australia Geological HICKMAN, A. H., 1990, Geology of the Pilbara Craton, in Third Survey, 1:250 000 Geological Series Explanatory Notes, 29p. International Archaean Symposium, Perth, 1990, Excursion TRENDALL, A. F., 1990, Hamersley Basin, in Geology and mineral Guidebook No. 5: Pilbara and Hamersley Basin edited by S. E. HO, resources of Western Australia: Western Australia Geological Survey, J. E. GLOVER, J. S. MYERS, and J. R. MUHLING: University of Memoir 3, p. 163–189. Western Australia, Geology Department and University Extension, TRENDALL, A. F., NELSON, D. R., de LAETER, J. R., and Publication no. 21, p. 2–13. HASSLER, S., 1998, Precise zircon U–Pb ages from the Marra HICKMAN, A. H., 2000, Geology of the Dampier 1:100 000 sheet: Mamba Iron Formation and the Wittenoom Formation, Hamersley Western Australia Geological Survey, 1:100 000 Geological Series Group, Western Australia: Australian Journal of Earth Sciences, Explanatory Notes, 39p. v. 45, p. 137–142. HICKMAN, A. H., in prep., Geology of the Cooya Pooya 1:100 000 VAN KRANENDONK, M. J., 1998, Litho-tectonic and structural map sheet: Western Australia Geological Survey, 1:100 000 Geological components of the North Shaw 1:100 000 sheet, Archaean Pilbara Series Explanatory Notes. Craton: Western Australia Geological Survey, Annual Review KOJAN, C. J., and HICKMAN, A. H., 1998, Late Archaean volcanism 1997–1998, p. 63–70. in the Kylena and Maddina Formations, Fortescue Group, west VAN KRANENDONK, M. J., 2003, Geology of the Tambourah Pilbara: Western Australia Geological Survey, Annual Review 1:100 000 sheet: Western Australia Geological Survey, 1:100 000 1997–98, p. 43–53. Geological Series Explanatory Notes, 57p.

13 Smithies

VAN KRANENDONK, M. J., HICKMAN, A. H., SMITHIES, R. H., NELSON, D. R., and PIKE, G., 2002, Geology and tectonic evolution of the Archaean North Pilbara Terrain, Pilbara Craton, Western Australia: Economic Geology, v. 97, p. 695–732. WIJBRANS, J. R., and McDOUGALL, I., 1987, On the metamorphic history of an Archean granitoid greenstone terrane, East Pilbara, Western Australia, using the 40Ar/39Ar age spectrum technique: Earth and Planetary Science Letters, v. 84, p. 226–242. WINGATE, M. T. D., 1999, Ion microprobe baddeleyite and zircon ages for Late Archaean mafic dykes of the Pilbara Craton, Western Australia: Australian Journal of Earth Sciences, v. 46, p. 493–500.

14 GSWA Explanatory Notes Geology of the Hooley 1:100 000 sheet

Appendix 1 Gazetteer of localities

Place name MGA coordinates Easting Northing

Grimms Bore 643600 7575000 Hooley Homestead 626300 7579600 Punduna Pool 642000 7612700 Wonga Well 624100 7592700

15 TheHOOLEY 1:100 000 sheet covers the southeast corner of the PYRAMID 1:250 000 sheet. These Notes describe the stratigraphy, structure, and mineralization of the area, which lies in the central part of the Archaean Pilbara Craton. The Yule Granitoid Complex (2945-2930 Ma) is a major feature of the East Pilbara Granite–Greenstone Terrane onHOOLEY , and contains unassigned greenstones as xenoliths or roof pendants. The Fortescue Group (2775-2630 Ma), and the Marra Mamba Iron Formation of the Hamersley Group unconformably overlie these rocks as part of the Hamersley Basin. They dip shallowly south-southwest with the Fortescue Group dominating outcrop onHOOLEY as a plateau. Pegmatite-hosted beryl, iron-rich regolith, and alluvial corundum have previously been of economic interest on the map area.

Further details of geological publications and maps produced by the Geological Survey of Western Australia can be obtained by contacting:

Information Centre Department of Industry and Resources 100 Plain Street East Perth WA 6004 Phone: (08) 9222 3459 Fax: (08) 9222 3444 www.doir.wa.gov.au AUSTRALIA 1Ý:Ý100Ý000 GEOLOGICAL SERIES GEOLOGICAL SURVEY OF WESTERN AUSTRALIA SHEET 2554

118°00À 10À 20À 118°30À

04 06 08 ì10 12 14 16 18 ì20 22 24 26 28 ì30 32 34 36 38 ì40 42 44 46 48 ì50 52 54 360 Geological boundary

21°30À 360

Órfb ñbu ñsq 180 21°30À

22 220 ñFr d ñur 80 ñgYpos 320 Órk 380 ñbu d ñgYmux ñgYpop 200 d d exposed...... 5 Ôao D d Ôaa Ôao ÔabÔw Ôc

220 400 5 Ôc Ôab 80 ñgYchn 180 Fault 300 Pilbara ñbuq Óc 180 420 80 ñgYcor Corung Yard

280 340 Óag d 85 d Ôw exposed...... 340 ñsqn Pilbaddy Well (abd) Ôaa Alluvial sand and gravel in rivers and creeks; clay, silt, and sand in channels on floodplains

320 80 240 220 220 ñbas 80

180 220 d

200 360 80 Ôao Overbank deposits; alluvial sand, silt, and clay in floodplains adjacent to main drainage channels concealed...... 200 70 300 d ñsqn ñsqn ñur Óc 240 70 Ôab Alluvial sand, silt, and clay in floodplains, with gilgai surface in areas of expansive clay

ñur QUATERNARY 85 îì20 Fold, showing axial trace ñFh 80 80 ñgYchn îì20 Creek ñFhu 75 d 180 Ôw Sheetwash deposits _ silt, sand, and pebbles in distal outwash fans; no defined drainage 80 ñba antiform; exposed, concealed......

260 Óc 400 Ôao Ôc Colluvium _ sand, silt, and gravel on outwash fans; scree and talus 240 380 180 Creek 0 280 landing ground (abd) 40 Óru ñbuq Small-scale fold axis, showing strike and dip 80 ñur ñba d d 40 ñgYpop d ñbag 80 55 syncline......

340 220 260 80 70 0 ñgYchn Z 40

260 ÓafÓak Óc Órfb Órk Óru Z-vergence......

22 ñFkbi Óc d Óag 80 40 Creek 300 ñgYcor Ócb 280 40 d 18 CAINOZOIC 360 PHANEROZOIC 220 75 80 Ôab Bedding, showing strike and dip 360 80 ñgYcorx 460 280 65 10 18 400 ñu ñbuq d ñba d Óaf Pisolitic limonite deposits, developed along palaeodrainage lines; dissected by recent drainage inclined......

280 400 200

ñFr 420 240 ñur 260 Ôc ñbag 60 d ñbas ñu ñu Óag Óag Alluvial gravel, unrelated to recent drainage; variably consolidated; dissected by recent drainage 260 d vertical...... ñur Óak Alluvial calcrete; massive, nodular, and cavernous limestone; variably silicified and dissected 75 ñur Óag d 80 Óc 60 ñbuq ñbas d overturned...... 65 Z Óc Colluvium _ sand, silt, and gravel on outwash fans; scree and talus 260 ñsq 300 40 400 ñFk 240 d 70 85 75 70 80 Ócb Colluvium with gilgai surface in areas of expansive clay; dissected by recent drainage strike and dip estimated from aerial photography RIVERÔaa 440 d Creek ñgYchn ñgYcorx

Spring 70 Ôaa 75 Z Órfb Ferruginous caprock over basalt 5 ñFh 16 5Ê15°...... 320 10 d

16 Peahwarrinah Spring ñur200 Órk Residual calcrete; massive, nodular, and cavernous limestone; mainly silicified

360 440 70

3 landing ground (abd) ñu 15Ê45°...... 00 Pilbaddy Óru Siliceous caprock over ultramafic rock ñbag65 ñbas 420 480 Ôaa 420 220 d Igneous layering, showing strike and dip 300 380 d ñFtsv 5 240 ñu

240 340 d inclined...... 28 ñbal Creek 0 440 200 260 200

220 ñgY d Dolerite dyke; interpreted from aeromagnetic data where dashed 240 480 360 60 Óag Igneous flow banding, showing strike and dip 380 340 420 Aboriginal Reserve 420 400 Óc 14 85 ñba ñu inclined...... 320 85 ñsqn Óag 14 Ôab 60 75 320 80 d Óag Metamorphic foliation, showing strike and dip 400 ñba 45 50 30 300 Punduna Pool 55 inclined...... 5 240 40 ñuk 65 c. 2595 MaÝâ 340 300 Óag ñHm MARRA MAMBA IRON FORMATION: chert, banded iron-formation, mudstone, and siltstone 10 Yard 70 Powdar vertical...... 10 30 40 Óag 280 Mungoona Creek 280 Ôaa 85 Mumbillina 35 d ñu Corung Hamersley Group Gneissic banding, showing strike and dip SHERLOCK d Brl 65 Aboriginal Reserve JEERINAH FORMATION 40 ñsq 12 inclined...... ñFh 240 Ôaa Óc 12 Óc ñgYpos c. 2686Ê2629 MaÝäÝå ñFjslg Carbonaceous mudstone and siltstone, chert, and local dolomite beds 10 380 Cleavage, showing strike and dip 5 ñu Ôc 380 400 Ôaa 80 d ñFhu Ôab inclined...... 240 65 340 d ñFjkd Dolomite and dolomitic shale

380 Óc Ôao 3 260 vertical...... 340 ñFtc 60 Ôc 300 70 ñFm 380 Ôc

220 360 ñFk d 220 35 ñu Crenulation cleavage, showing strike and dip 40 460 Bore 85 20 320 70 Cor îì10 Variegated, light-coloured mudstone and siltstone 3 ñFjsl inclined......

îì10 80 380 400 Ôab landing ground (abd) 220 Airphoto lineament ñbuq Billadunna Spring 400 70 240 ñgYt ñgYt ñbal

240 40

5 Ôc 75 ñFjo Woodiana Member: quartz-rich sandstone, chert, chert breccia, and mudstone; locally includes volcanogenic lithic sandstone fracture pattern...... 10 220 460 5 80

Creek 75 320 ñgYpop Óag Óc 85 4 ñu Formed road......

380 20 440 ñFk c. 2717 MaÝè ñFm MADDINA FORMATION: massive, vesicular, and amygdaloidal basalt and basaltic andesite

360 300 MUMBILLINA BLUFF 80 Ôab 380 280 ñFr 70 08 Major track......

08 260

300 Óc 280 240 Track...... 260 240 Ôao Hope 340 ñu ñFmx Basaltic volcaniclastic breccia 40 ñbal Fence, generally with track...... ñFhu 65 420 420 ñFk 400 Óc ñFkh Homestead...... Hooley 380 Ôc

Ôc Ôc ñgYt Ôaa 75 ñFmk Kuruna Member: basaltic to andesitic volcaniclastic sandstone, mudstone, chert, and dolomite 260 ñgYcorx Building...... 420 Ôaa 460 340 60 06 Yard 70 Miaguarina Pool Óc Yard...... 340 ñgYt 06 3 440 60 TUMBIANA FORMATION: mafic to felsic volcaniclastic sandstone, tuff, and fine- to medium-grained clastic sedimentary rock; minor 20 ñuk ñgYco c. 2719 MaÝê Reserve boundary...... Órk 40 360 ñFt

5 320 ñFkbi 400 300 Óag basalt, chert, dolomite, and limestone 380 landing ground (abd) 420 ñgYpos 45 300 Breakaway......

480 Óag 320 480 60 65 340 ñFkh Contour line, 20 metre interval...... 220 Ôaa 320 340 ñFtsvs Volcaniclastic sandstone, tuff, and fine- to medium-grained clastic sedimentary rock 420 15 ñur ñFkbi 300 240 85 280 HAMERSLEY BASIN 440 460 5 460 ñFk 300 360 30 ñbal ñFkh ñFkbi Mount Bruce Supergroup 50 Ôc 320 ñFkh ñFtsv 60 320 04 ñFtsvb Volcaniclastic sandstone, tuff, and clastic sedimentary rock with locally abundant basalt sheets and dykes with peperitic margins ñFkh Fortescue Group Watercourse with ephemeral pool or waterhole......

460 Ôc 300 340 04 320 Pool 5 ñgYcorx ñgYcorx Volcaniclastic sandstone, carbonate-rich tuff, and volcaniclastic mudstone, and siltstone; locally abundant layers of dark grey Pool...... 40À 460 60 ñFkh 360 2 40À ñFtsv 400 280 siliceous stromatolitic dolomite and limestone Spring...... Spring 10 5 Yard

ñgY Ôc 380 C Bore, well...... Bore Well

Table Top Bore (abd) 380 ñFtc Meentheena Carbonate Member: dark grey stromatolitic dolomite and limestone, carbonate-rich tuff, mudstone, and siltstone 360 460 280 300 280 480 320

340 320 Windpump...... 400 460 B 360 02 Dam, tank...... Dam Tank 02 360 380 440 400 ñFkh 340 ñFk KYLENA FORMATION: massive and amygdaloidal basalt, basaltic andesite, and dacite; local high-Mg basalt and rhyolite Abandoned...... (abd) 380 ñFkh 340 ñFkh ñFkh 360 420 Position doubtful...... (PD) 420 WEST PILBARA MINERAL FIELD Massive and amygdaloidal basalt, and mafic volcaniclastic rocks with sericite and pyrophyllite (hydrothermal) alteration along

440 360 460 340 ñFkh 460 epithermal veins and bedding planes 320 480 380 380 ñFkh 400 Mineral deposit...... ñFm 500 460 ñFkh ñFkh 5 400 300 Mumbillina îì00 ñFkbi Basaltic andesite with minor basalt and andesite Prospect...... 420 îì00 C H I C H E S T E R 400 Ôaa ñFkh 320 Mineral exploration drillhole, showing subsurface data...... ñHm 400 420 ñFtc 5 260 420 Creek 480 400 Mineral occurrence...... 420 4 400 c. 2760 MaÝäÝì ñFh HARDEY FORMATION: sandstone, conglomerate, siltstone, shale, and felsic tuff 40 Bore (abd) 380 360 5 Mineral and rock commodities 5 3 00 5 ñFkh 300 500 440 480 400 ñFtsv ñFhu Felsic tuff, tuffaceous sandstone, siltstone, and shale; interbedded; locally conglomerate Beryl...... Brl 360 ñFkh 360 360 ñFtsvb 340 98 320 300 Corundum...... Cor 98 ñFk 380 480 Ôao Powdar Iron...... Fe ñFm 460 320 ñFk 340 400 c. 2770 MaÝäÝî ñFr MOUNT ROE BASALT: massive, vesicular, and glomeroporphyritic basalt

400 Yard Ócb M U N G A R O O N A R A N G E PILBARA CRATON 5 ñFt 340 360 360 480 380 5 ñgY

ñFtc 96 ARCHAEAN 400 RIVER 380 320

96 320 460 480 400 4 360 RIVER 40 280 420 460 300 360 340 420 360 ñgYpop ñgYpos

480 ñFtsv 380

400 SHERLOCK 420 460 300 INTERPRETED BEDROCK GEOLOGY

360 ñFtc 94 ñgYmux ñgYt 94 300 320 ñgYmu d ñgYch 340 ñbu ñsq SHERLOCK 5 460 ñFh d d ñgYch 480 300 ñsq ñgYi 460 300 ñFtsv ñFh ñgYco ñgYcorx ñFr d ñFm 380 ñgYco ñgYcor ñgYchn ñFk d d d ñgYch Wonga Well 320 Creek ñsq ñgY d ñbu 360 320 340 d ñsq 380 420 5 360 YULE GRANITOID COMPLEX

400 420 280 360 400 92 ñgY Granitoid rock, unassigned; age uncertain; typically strongly weathered; metamorphosed d ñgYpo

ñgYco R A N G E 340 d 92 5 5 2935 MaÝð POWDAR MONZOGRANITE ñFh d 5 ñFm 380 ñgYpop Porphyritic monzogranite ñFh 5 400 380 340 320 ñgYt ñu 440 ñFtsvb 360 360 ñgYpos Seriate-textured monzogranite ñba 480 MUNGAROONA GRANODIORITE 340 Tarraninnia Spring 340 ñu Pilbaddy 320 380 ñgYmux Hornblende(Êbiotite)-bearing granodiorite and monzogranite with greenstone and granitoid gneiss rafts and xenoliths ñba ñFm 300 360 HornblendeÊbiotite tonalite 400 ñgYt îê90 ñgY Órk ñgYco COCKERAGA LEUCOGRANITE: leucocratic biotite(Êhornblende) tonalite and granodiorite and subordinate monzogranite; locally abundant pegmatite, and 380

Sherlock Bore (abd) Hood Well (abd)(PD) 320 îê90 Tanama Spring 360 greenstone and granitoid gneiss xenoliths; weakly metamorphosed 460 320 400 ñFm ñgYcor Leucocratic biotite(Êhornblende) tonalite and granodiorite and subordinate monzogranite with well-developed schlieric banding; locally 400 380 abundant granitoid gneiss xenoliths

380 ñFt ñFt ñFk Tank (abd) ñgYcorx Leucocratic biotite(Êhornblende) tonalite and granodiorite and subordinate monzogranite with well-developed schlieric banding and 360 5 ñFk ñFtsv

460 10 340 locally abundant greenstone and granitoid gneiss xenoliths Ócb Centenary Bore 5 380 Órk 88 CHEEARA MONZOGRANITE 5 ñgYchn Gneissic monzogranite to granodiorite ñFk 88 Óc 480 360 380 440 Ócb 480 400 ñFm Warrina Spring Órk 480

Ôaa 360 ñFjsl ñsq ñsqn Creek 360

Óc Ôab 460 Hooley 400 400 320 10 440 380 440 Cheedy Well ñsq QuartzÊmuscovite schist and quartzite Yard Cheedy Pool 360 86 Goanna Well Yard Yard 400 ñsqn Quartzite with locall banded quartz and quartzÊfeldsparÊamphibole paragneiss 86 Jeffries Well 340

460

460 420 Órk ñFm 5 ñbañbag ñbal ñbas ñbu ñbuq ñFj d 50À 360 50À ñFtsvs 420 ñFjo 5 ñFtsv 10 40 5 5 ñba Amphibolite; fine to medium grained; massive to strongly foliated 0 ñFm 84 ñbag Medium-grained amphibolite with abundant layers, veins, and irregular patches of tonalite; massive to strongly foliated ñHm d 480 420 d ñFm 84 420 Órk ñbal Leucocratic amphibolite; medium grained; massive to strongly foliated 460 40 ñFk ñFjsl 5 0 ñbas Amphibolite and actinolitic schist 400 ñFm 400 ñFtsv 420 ñHd ñbu Interleaved mafic and ultramafic rocks; metamorphosed

Ôab 5 ñFj 440

400 ñbuq Interleaved mafic and ultramafic rocks, quartzÊmuscovite schist, and quartzite 5 400 380 ñFjslg 5 fence (abd) 380 480 Óc SCALE 1:Ý500Ý000 10 Creek 460 4 420 0 5 10 15 20 20 5 Ôaa 82 ñu ñuk ñur Ócb 5 82 Órk Kilometres 5 460 400 Pilbaddy Gap Pool 360 Windinginna Well ñFm 5 380 5 Pilbara Supergroup (no stratigraphic subdivision) ñu Ultramafic rock, undivided; metamorphosed Creek ñFtsv Óc ñuk Metamorphosed peridotitic komatiite; olivine spinifex texture; serpentineÊtalcÊtremolite rock 10 400 d Dolerite dyke 10 5 Ôab ñur Tremolite-rich schist; after ultramafic rock 30 440 Ócb Pindrinna Well (PD) Óaf Ôab 400 Óc ñFm 5 ñFtsv îê80 400 ñHd Wittenoom Formation 420 îê80 380 Yards 5 Ôaa 440 460 d Group ñHm Marra Mamba Iron Formation Hooley Ellina Hooley Hamersley 460 ñFtsv Ôao Yard (abd) Órk 440 Mountbatten Well Óaf ñFj Jeerinah Formation

Ócb WHINGAWARRENA HILL ñFm 480 ñFm Maddina Formation Ôaa 10

Mount Florence Homestead 19 km 19 Homestead Florence Mount A Creek Yard (abd) Creek Óc Tumbiana Formation landing ground 420 ñFt ñFjsl 78

Hooley ñFk Kylena Formation HAMERSLEY BASIN 78 Chudyearina Kyalina Pool

ñFm Fortescue Group ñFjkd Yards (abd) Cheerana Pool Corkbark Well (abd) 5 460 ñFh Hardey Formation Mooliana Well 5 ñFtsvs 10 460 Cheetawona Pool Carlercalera Pool Marie Louise Bore 10 ñFm ñFr Mount Roe Basalt ñFjslg Pool 440 Óak Burgess Bore 460 420 10 d 5 ñFmk Well (abd) 460 ñgY 10 5 Yards 400 5 Hutt Yards Upper Cheetawona 5 76 ñHm Pool ñFm ñgYi ñgYpo 76 ROEBO ñHm Fe Ôab Ócb d TN 440 Grim Well (abd) ñgYmu ñgYt Ôao URNE ñFjslg 480 460 Yard PILBARA CRATON Yammera Ôab GN Ôab Yard Grimms Bore ñsq ñba ñbu ñu ñgYco ñgYch Órk 5 Bore 5 Yards Órk Órk Gap Well Ngulkaminningtha ñsq QuartzÊmuscovite schist and quartzite YULE GRANITOID COMPLEX Kelly Well (abd) 5 Pool Óc 5 Ócb ñbaAmphibolite ñgY Granitoid rock, unassigned (abd) 74 Hancocks Dam WITTENOOM ñFjkd Yandina Bore ñbu Metamorphosed interleaved mafic and ñgYi Interleaved granodiorite, granitoid, and pegmatite 5 Órk ñFm Unassigned 74 5 nce Cottage Well 480 d 480 480 Órk GRID / MAGNETIC 5 Órk fe ultramafic rocks ñgYpo Powdar Monzogranite Ôaa Óc Órk Pilbara Supergroup ñFm 480 ANGLE 2°

460 ñu Ultramafic rock, metamorphosed ñgYmu Mungaroona Granodiorite Ôao ñgYt HornblendeÊbiotite tonalite 480 Clark Well (abd) GRID N.T. 380 C ñgYco Cockeraga Leucogranite ñFjo re ñFmx Órk 480 460 ek Ócb Brookanthana Well CONVERGENCE ñgYch Chearra Monzogranite FORTESCUE Ôab Yard 0.5° Qld 5 72 (abd) Ôab W.A. 72 5 (abd) 440 Óc fence 10 480 Ócb ñFm Óc ROAD Ôaa S.A. 440 fence Ócb Óc ñFmx 420 Ôc N.S.W. RIVER 5 480 460 500 480 Óc 5 Órk A.C.T. 5 80 5 5 îê70 Óak ñHm 5 True north, grid north and magnetic north Vic. îê70 85 Mooliande Well 500 5 Ócb 420 Óc are shown diagrammatically for the centre Carboy Well (abd) 400 480 ñFmx of the map. Magnetic north is correct for Ôab d Órk PEELANGOOTHARANA PEAK landing ground (abd) Tas. Panthangoona Tank 2002 and moves easterly by about 0.1° in

Snakewood ñFm 440 Óc Yard 2 years. G IC A L S U L O R Well 500 V ñFm O E E Ôaa Y 460 Bore (abd) Department of Geological Survey of G

Ôab W A E 68 I Ôaa Mineral and Petroleum Resources Western Australia S L T A ñFm ñFm E T R 420 ñFmx 480 R N A U S Ôao Óc 440 (abd) 480 îê68ôôôÜN fence 480 460 480 Óc Salt Spring Well (abd) 460 460 480 ñFjsl ñFjo Órk ñFm 480 CLIVE BROWN, M.L.A. JIM LIMERICK TIM GRIFFIN Spring MINISTER FOR STATE DEVELOPMENT DIRECTOR GENERAL DIRECTOR 22°00À 22°00À ì04ôôôÜE 06 08 ì10 12 14 16 18 ì20 22 24 26 28 ì30 32 34 36 38 ì40 42 44 46 48 ì50 52 54 Wittenoom 54 km 118°00À 10À 20À 118°30À

PRODUCT OF THE NATIONAL Geology by R. H. Smithies 2000Ê2001 GEOSCIENCE AGREEMENT G E O S C I E N C E Geochronology by: A U S T R A L I A DIAGRAMMATIC SECTIONS (1) A. F. Trendall et al., 1998, Australian Journal of Earth Sciences, v. 45, p. 137Ê142. A B C D (2) N. T. Arndt et al., 1991, Australian Journal of Earth Sciences, v. 38, p. 261Ê281. (3) D. R. Nelson et al., 1999, Precambrian Research, v. 97, p. 165Ê189. SHEET INDEX SCALE 1:100Ý000 (4) D. R. Nelson, 1998, GSWA Record 1998/2, p. 133Ê135. MUNGAROONA RANGE COOYA POOYA MOUNT WOHLERSATIRIST WODGINA NORTH SHAW MARBLE BAR 1000 0 1 2 34 8910 (5) D. R. Nelson, 2001, GSWA Record 2001/2, p. 175Ê177. 56 7 ñFtc (6) R. T. Pidgeon, 1984, Australian Journal of Earth Sciences, v. 31, p. 237Ê242. 2355 2455 2555 2655 2755 2855 ñFk ñFkh PYRAMID MARBLE BAR Metres UNIVERSAL TRANSVERSE MERCATOR PROJECTION Kilometres ñFtsvs ñFm ñFk ñsqn ñbag (7) M. T. D. Wingate, 1999, Australian Journal of Earth Sciences, v. 46, p. 493Ê500. SEA LEVEL ñFm ñFtsvb ñsqn SEA LEVEL SF 50-7 SF 50-8 HORIZONTAL DATUM: GEOCENTRIC DATUM OF AUSTRALIA 1994 ñFtsv ñu ñbag ñba ñgYchn (8) D. R. Nelson, 2000, GSWA Record 2000/2, p. 82Ê85. MILLSTREAM MOUNT BILLROTH HOOLEY WHITE SPRINGS TAMBOURAH SPLIT ROCK ñFkbi ñbal ñu VERTICAL DATUM: AUSTRALIAN HEIGHT DATUM ñuk 2354 2454 2554 2654 2754 2854 ñur Edited by C. Strong and G. Loan ñFk ñgYcorx ñu ñbuq Grid lines indicate 1000 metre interval of the Map Grid Australia Zone 50 ñbal ñbuq Cartography by S. Coldicutt, G. Wright, and B. Williams ñgYpos JEERINAH McRAE WITTENOOM MOUNT GEORGE MOUNT MARSH WARRIE ñbuq Topography from the Department of Land Administration Sheet SF 50-7, 2554, The Map Grid Australia (MGA) is based on the Geocentric Datum of Australia 1994 (GDA94) ñbas ñba 2353 2453 2553 2653 2753 2853 ñu ñbas ñsqn with modifications from geological field survey MOUNT BRUCE ROY HILL GDA94 positions are compatible within one metre of the datum WGS84 positions

ñur GEOCENTRIC DATUM OF AUSTRALIA SF 50-11 SF 50-12 2 km ñgYt 2 km Mineralization and rock commodity information from non-confidential data held in the WAMIN ROCKLEA MOUNT LIONEL MOUNT BRUCE MUNJINA WEELI WOLLI ROY HILL ñu ñur ñgY ñu database, GSWA, at 15 May 2002 2352 2452 2552 2652 2752 2852 ñgYchn d ñba Published by the Geological Survey of Western Australia. Digital and hard copies of this map are available from the Information Centre, Department of Mineral and Petroleum Resources, 1:100Ý000 maps shown in black ñgYpos 100 Plain Street, East Perth, WA, 6004. Phone (08) 9222 3459, Fax (08) 9222 3444 1:250Ý000 maps shown in brown ñgYpos WebÝ www.mpr.wa.gov.au EmailÝ geological [email protected] SHEET 2554 FIRST EDITION 2002 4 km 4 km The recommended reference for this map is: Version 1 Ê June 2002 SMITHIES, R. H., 2002, Hooley, W.A. Sheet 2554: Western Australia Geological Survey, 1:100Ý000 Geological Series. ¦ Western Australia 2002