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Chapter 3.6 The Narryer Terrane, Western Australia: A Review

Chapter 3.6 The Narryer Terrane, Western Australia: A Review

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276



Chapter 3.6: The Narryer Terrane, Western Australia: A Review



Fig. 3.6-1. Map showing Superterranes, Terranes and the Murchison Domain in the Yilgarn Craton

of Western Australia (based on Cassidy et al., 2006).



3348 ± 43 Ma using multicomponent samples. This age was comparable to those obtained

by Arriens (1971) from the southwestern Yilgarn Craton and appeared to substantiate the



Fig. 3.6-2. (Next page.) Map of the Western Gneiss Terrane as originally defined by Gee et al. (1981)

and modified from Myers (1990), illustrating the earlier interpretation of distribution of gneissic

rocks along the western margin of the Yilgarn Craton.



3.6-2. Historical



277



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Chapter 3.6: The Narryer Terrane, Western Australia: A Review



link between the southern and northern parts of the ‘Western Gneiss Terrain’. Subsequent

dating (de Laeter at al., 1981b), using the Sm-Nd whole-rock technique, of two of these

samples yielded model ages (TCHUR ) of 3630 ± 40 Ma and 3510 ± 50 Ma, considerably

older than any ages previously obtained from the Yilgarn Craton. The oldest model age

was obtained from layered monzogranitic gneiss, whereas the younger age was obtained

from more leucocratic granitic gneiss that was intrusive into the former.

A detailed map of the Mt. Narryer area was prepared by I.R. Williams in 1981–1982

and J.S. Myers in 1983, but not published until 1987 (Fig. 3.6-3) (Williams and Myers,

1987). As a consequence, the subdivision of the gneisses proposed therein was published

first in Myers and Williams (1985). The rocks at Mt. Narryer were later referred to as the

‘Narryer Gneiss’ (Myers, 1988a).

Investigations of the area coincided with the development of the SHRIMP ion microprobe at the Australian National University (ANU) in Canberra (Compston et al., 1984).

This instrument allowed, for the first time, precise in situ Th-U-Pb analysis of individual

zircon grains at a ∼25 micron spot size, with the possibility of placing more than one

analytical site per grain. Following a detailed investigation of the ancient gneisses and

quartzites in the Toodyay area by Nieuwland and Compston (1981) using conventional

multigrain zircon U-Pb methods, it was a natural progression for the Canberra group to

undertake a detailed study of the recently-identified rocks of apparently similar age near

Mt. Narryer.

An initial investigation of the Mt. Narryer area commenced using the SHRIMP ion

microprobe, including not only a study of the ancient gneisses, but also of the detrital zircon

population in the granulite facies quartzites and conglomerates. This led to the exciting

discovery of four detrital zircon cores with ages ranging from 4110 to 4190 Ma, the oldest

crustal remnants identified on Earth at that time (Froude et al., 1983). The four grains were

interpreted to have the same age (∼4150 Ma; no uncertainty quoted) and were obtained

from a quartzite (GSWA sample 71932) collected ∼2.5 km NNE of Mt. Narryer. This

finding led to additional studies and ultimately to a major field and analytical program

by the Australian National University (the ‘First Billion Years’ project) aimed at further

characterising the area.

In 1983, as part of a program to examine the five greenstone belts that had been identified within the Western Gneiss Terrain by Gee et al. (1981) (Fig. 3.6-2), the first detailed

mapping of the Jacks Hills at a scale of 1:10,000 was completed by final year undergraduate students of the Western Australian Institute of Technology (now Curtin University of

Technology) under the guidance of John Baxter, Robert Pidgeon and Simon Wilde. The

Jack Hills was initially considered to be a greenstone belt (Elias, 1982), but was found

to consist predominantly of metasedimentary rocks, including both chemical and clastic

varieties, enclosed by granitic gneisses (Baxter et al., 1984). However, unlike Mt. Narryer, the metamorphic grade was greenschist to amphibolite facies (Baxter et al., 1984).

A suite of samples, including quartzite and conglomerate, was collected for U-Pb zircon



Fig. 3.6-3. (Next page.) Detailed map of Mt. Narryer (modified from Williams and Myers (1987)).



3.6-2. Historical



279



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Chapter 3.6: The Narryer Terrane, Western Australia: A Review



geochronology in both 1983 and 1984, when the mapping exercise was repeated. In order

to test if there was any similarity with the Mt. Narryer metasedimentary rocks, zircons

obtained from a greenschist facies conglomerate exposed on Eranondoo Hill (Fig. 3.6-4)

were run on the ANU SHRIMP I ion microprobe. Two zircons with ages of 4276 ± 12 Ma

were identified, making these the oldest known crustal components on Earth at that time

(Compston and Pidgeon, 1986).

In subsequent years, further detailed mapping and geochronological investigations in

the northern Yilgarn Craton led to the better characterisation of the Narryer Terrane

(Williams et al., 1983; Williams and Myers, 1987; Myers, 1988a, 1988b; Kinny et al.,

1988; Kinny et al., 1990; Wilde and Pidgeon, 1990; Myers, 1990a; Nutman et al., 1991;

Maas and McCulloch, 1991; Maas et al., 1992; Myers, 1993; Kinny and Nutman, 1996;

Pidgeon and Wilde, 1998). However, the level of activity had started to wane by the mid1990s.

Following Compston and Pidgeon (1986), some further work was undertaken on the

same suite of zircons extracted from the metaconglomerate at Eranondoo Hill. Köber et al.

(1989) published the results of stepwise single zircon evaporation measurements, whilst

Amelin (1998) analysed crystal fragments by standard U-Pb isotope dilution using thermal

ionisation mass spectrometry; both studies essentially reproducing the earlier SHRIMP

results.

In 1998, a re-investigation of the ancient zircon population from Eranondoo Hill at

Jack Hills was undertaken by a team from Curtin University and the University of Wisconsin, incorporating both SHRIMP U-Pb and CAMECA IMS 4f oxygen data on a new

suite of zircon grains extracted from the same sample (W74) analysed by Compston and

Pidgeon (1986). This led to the identification of a zircon that contained a portion with

an age of 4404 ± 8 Ma (Wilde et al., 2001); by far the oldest age ever obtained from

crustal material on Earth. A companion investigation began in 1999 with a team from

UCLA and Curtin University collecting new material from the area, including from the

same sample site where W74 was obtained. Importantly, both studies obtained evidence

from the W74 site for elevated δ 18 oxygen values in the ancient zircon population, implying zircon growth in rocks previously subjected to interaction with surface waters

(Wilde et al., 2001; Mojzsis et al., 2001; Peck et al, 2002). This has led to the hypothesis of a cool early Earth (Valley et al., 2002; Valley, 2005), implying the early

development of oceans on the planet. As with the initial studies in the 1980s, these recent investigations coincided with new technological advances, this time involving the

ability to analyse oxygen isotopes of single zircon grains in situ with great precision

using the CAMECA IMS 1270 (and now the 1280) ion microprobe (Cavosie et al.,

2005) and this has opened up an exciting new time for studying these earliest remnants of Earth’s continental crust. The ability to measure precise hafnium ratios in single zircon crystals has also provided an important new advance (Harrison et al., 2005).

These aspects are more fully described in a companion paper (Cavosie et al., this volume).



3.6-2. Historical

281



Fig. 3.6-4. Sketch map of the Jack Hills (modified from Spaggiari (2007a)).



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Chapter 3.6: The Narryer Terrane, Western Australia: A Review



3.6-3. CHARACTERISTICS OF THE NARRYER GNEISS COMPLEX

3.6-3.1. Overview

Myers (1990a) presented the first attempt at subdividing the Yilgarn Craton into a number of tectonostratigraphic terranes, and further developed this idea in subsequent years

(Myers, 1993, 1995). He proposed the term ‘Narryer Terrane’ to cover the area previously

referred to as the ‘Narryer Gneiss Complex’, at the same time recognising that the latter is

merely a subcomponent of the terrane, since extensive areas of Late Archean granites had

subsequently been recognised throughout the area. In the most recent revision of terranes

in the Yilgarn Craton, Cassidy et al. (2006) have retained this terminology and we have

adopted this in the present paper. However, we retain the term “Narryer Gneiss Complex”

when referring to the >3 Ga rocks present within the area.

The Narryer Gneiss Complex is one of the largest intact pieces of ancient continental

crust remaining on Earth, occupying a significant portion of the Narryer Terrane, which

exceeds 30,000 km2 in area (Myers, 1988a). The western margin of the Narryer Terrane

(Fig. 3.6-5) is defined by the Darling Fault, and the northern margin by the Errabiddy

Shear Zone, along which the Glenburgh Terrane was accreted to the Yilgarn Craton during the 2005 to 1960 Ma Glenburgh Orogeny (Occhipinti et al., 2004; Occhipinti and

Reddy, 2004). The southern margin marks the boundary with the Younami Terrane, a major

granite-greenstone association in the Yilgarn Craton (Cassidy et al., 2006), and is defined

by the Balbalinga and Yalgar Faults; the latter interpreted as a major dextral strike-slip

fault (Myers, 1990b, 1993). The structural history of this fault is poorly understood, and

the boundary is likely to have been reworked and cryptic (Fig. 3.6-5) (Nutman et al., 1993a;

Spaggiari, 2007a; Spaggiari et al., in review).

The Narryer Gneiss Complex (Myers, 1988a) is composed of granitoids and granitic

gneisses ranging in age from Paleo- through to Neoarchean (Kinny et al., 1990; Nutman et

al., 1991; Pidgeon and Wilde, 1998). These rocks are locally interlayered with deformed

and metamorphosed banded iron formation (BIF), mafic and ultramafic intrusive rocks,

and metasedimentary rocks (Williams and Myers, 1987; Myers, 1988a; Kinny et al., 1990).

More extensive sequences of amphibolite to granulite facies metasedimentary rocks occur

at Mt. Narryer, whereas greenschist to amphibolite facies BIF, mafic and ultramafic rocks,

and both Archean and Paleoproterozoic clastic metasedimentary rocks occur at Jack Hills

(Elias, 1982; Williams et al., 1983; Wilde and Pidgeon, 1990; Cavosie et al., 2004; Dunn

et al., 2005; Spaggiari, 2007a).

The early Archean gneisses of the Narryer Terrane have been interpreted as an allochthon that was thrust over ca. 3000 to 2920 Ma granitic crust of the Youanmi Terrane,

prior to, or during, the period of late Archean granitic magmatism that stitched the two

terranes (Nutman et al., 1993a). Although there is evidence of deformation prior to the intrusion of these granites, the deformation that produced the main tectonic grain is believed

to have occurred at amphibolite facies between ca. 2750 and 2620 Ma, and to have affected

both terranes (Myers, 1990b). Three phases of folding are recognised; recumbent folding



3.6-3. Characteristics of the Narryer Gneiss Complex



283



Fig. 3.6-5. Reduced to pole, total magnetic intensity image of the northwestern Yilgarn Craton

showing the Narryer Terrane and part of the Murchison Domain of the Youanmi Terrane. Terrane

boundaries and major faults modified from Myers and Hocking (1998), and after Occhipinti et al.

(2004) and Spaggiari (2006).



associated with thrusting (D1 ), followed by two phases of upright folding with generally

northeast or east-northeast trending axes (D2 and D3 ; Myers, 1990b).

The Paleoproterozoic Capricorn Orogeny (1830–1780 Ma) produced intracratonic, predominantly greenschist facies, dextral transpressional reworking of both the northern and

southern margins of the Narryer Terrane. These effects are evident in the Errabiddy Shear

Zone (Occhipinti and Reddy, 2004), the Jack Hills metasedimentary belt (Spaggiari, 2007a;

Spaggiari, 2007b; Spaggiari et al., 2007) and the Yarlarweelor Gneiss Complex in the



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Chapter 3.6: The Narryer Terrane, Western Australia: A Review



northern part of the Narryer Terrane. The latter was deformed, metamorphosed and intruded by granites and dykes between approximately 1820 and 1795 Ma (Sheppard et

al., 2003). This involved a two stage process of intrusion during compression, followed

by intrusion during dextral strike slip deformation. Deformation related to the Capricorn

Orogeny has been interpreted to extend as far south as the northern end of the Mingah

Range greenstone belt within the Murchison Domain of the Youanmi Terrane (Fig. 3.6-5;

Spaggiari, 2006; Spaggiari et al., in review). There is evidence that the Yalgar Fault was

probably active during the Capricorn Orogeny, but whether the Yalgar Fault is a true terrane

boundary is unclear.

3.6-3.2. Mt. Narryer Region

Myers and Williams (1985) recognised that most rocks at Mt. Narryer have been metamorphosed to granulite facies and undergone multiple deformation episodes. They identified

two major suites of granitic gneisses: the older Meeberrie gneiss and the younger Dugel

gneiss, which yielded Sm-Nd (TCHUR ) model ages of 3630 ± 40 Ma and 3510 ± 50 Ma,

respectively (de Laeter et al., 1981b). Within the Dugel gneiss, fragments of a layered basic

intrusion were recognised and referred to as the Manfred Complex (Myers and Williams,

1985; Williams and Myers, 1987). In addition, quartzites and metaconglomerates make up

the core of Mt. Narryer itself.

3.6-3.2.1. Meeberrie gneiss

The Meeberrie gneiss is composed of alternating bands of quartzo-feldspathic and biotiterich units that define a prominent layering (Fig. 3.6-6(a,b)). Some components were

originally porphyritic, now occurring as deformed augen porphyroclasts, and the whole

sequence is dominantly composed of monzogranite. However, later work has shown that

many rocks are really part of the tonalite-trondhjemite-granodiorite (TTG) suite (Nutman

et al., 1991; Pidgeon and Wilde, 1998). The early biotite granitoid was intruded by pegmatites and the whole complex brought into layer-parallelism by subsequent deformation.

Sm-Nd (TCHUR ) model ages of 3630 ± 40 Ma (de Laeter et al., 1981b), and 3710 ± 30 Ma

and 3620 ± 40 Ma (de Laeter et al., 1985) were obtained from near Mt. Narryer, whereas

zircon cores from the sample giving the 3630 ± 40 Ma Sm-Nd age, obtained 7.5 km NNE

of Mt. Narryer, gave SHRIMP U-Pb ages of 3678 ± 6 Ma (Kinny et al., 1988). The oldest

known component of the Meeberrie gneiss is a tonalite collected 3 km south of the Jack

Hills, with a SHRIMP U-Pb age of 3731 ± 4 Ma (Nutman et al., 1991): this is the oldest known rock in Australia. Another Meeberrie gneiss sample, collected 1 km east of the

above, has a distinctly younger age of 3597 ± 5 Ma, indicating the composite nature of

the Meeberrie gneiss. Biotite from two samples of Meeberrie gneiss recorded K-Ar ages

of 1887 ± 34 Ma and 1778 ± 32 Ma (Kinny et al., 1990), clearly establishing that younger

events have affected the Mt. Narryer area.

A later SHRIMP ion microprobe zircon U-Pb study by Kinny and Nutman (1996), centred around Mt. Narryer, identified three main age populations in the Meeberrie gneiss:

at ∼3670, 3620 and 3600 Ma, with minor older components at ∼3730 Ma and younger



3.6-3. Characteristics of the Narryer Gneiss Complex



285



Fig. 3.6-6. Field photographs of gneisses and granitoid rocks in the Narryer Terrane. (a) Meeberrie

gneiss at site C of de Laeter et al. (1981a) that formed part of the data-set recording a Rb-Sr isochron

age of 3348 ± 43 Ma; hammer is ∼32 cm long. (b) Meeberrie gneiss at site Y21, 3 km south of

Jack Hills, where sample 88–173 was collected. It yielded an age of 3731 ± 4 Ma (Nutman et al.,

1991), making it the oldest rock in Australia; length of photo ∼1 m. (c) Dugel gneiss at type locality,

10 km NNE of Mt. Narryer. The gneiss is cut by a Neoarchean aplite dyke; hammer is ∼30 cm long.

(d) Single plagioclase crystals and anorthosite pods in Dugel gneiss at same locality as (c); hammer

is 32 cm long. (e) Eurada gneiss at type locality near Eurada Bore, where a ∼3480 Ma zircon age was

obtained from sample MN 10 by Kinny (1987); length of photo ∼60 cm. (f) Deformed porphyritic

granite, ∼1 km south of Meeberrie gneiss at site C of de Laeter et al. (1981a); pencil is 15 cm long.

All photographs courtesy of Pete Kinny.



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Chapter 3.6: The Narryer Terrane, Western Australia: A Review



Fig. 3.6-6. (Continued.)



components at ∼3300 Ma. Kinny and Nutman (1996) showed that the gneiss consisted of

multiple components down to centimetre scales and they emphasized the importance of

working in low strain zones, where original intrusive relationships may still be preserved:

elsewhere, the rocks approach migmatite. A simple age population of ∼3620 Ma was also

obtained from a gneiss at Mt. Murchison (Fig. 3.6-5) by Kinny and Nutman (1996), who

emphasised that it was impossible to quote a single age for the Meeberrie gneiss in the Mt.

Narryer region; it is a polyphase migmatite with ages ranging from 3730–3300 Ma.

3.6-3.2.2. Dugel gneiss

The Dugel gneiss occupies large areas of the Narryer Gneiss Complex and is dominantly

syenogranite, although it ranges to monzogranite in composition (Fig. 3.6-6(c)). Veins of



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