Zhen & Nicoll: Canning Basin Serratognathus bilobatus Fauna 
3 
LU 
Balto-Scandian 
Canning Basin, WA 
CD 
< 
conodont Zones 
Lithostratigraphy 
Conodont Zones 
O. evae 
Gap Creek 
Formation 
? 
Z 
P. elegans 
O. communis 
< 
O 
_| 
C 
upper 
? 
LL. 
O 
fa 
(150 m) 
P. adami- 
S. bilobatus 
P. proteus 
E 
o 
Ll_ 
"33 
middle 
(143 m) 
z 
< 
o 
ra 
E 
LU 
lower 
(142 m) 
P. parallelus 
o 
Q 
< 
5 
P. deltifer 
Kudata Dolomite 
? 
LU 
0£ 
1- 
Cordylodus 
Kunian Sandstone 
Guizhou 
South China 
Hebei 
North China 
Newfoundland 
Canada 
> = 
is 
— <D 
O. evae 
O. communis 
P honghua- 
yuanensis 
S. diversus 
T. bifid us 
Tongzi 
Formation 
lower 
Beianzhuang 
Formation 
P. paltodiformis 
S. extensus 
S. bilobatus 
Scalpellodus 
tersus 
Yeli Formation 
O. evae 
P elegans 
P ad ami 
P. oepiki 
P giberti 
Fig. 2. Conodont biostratigraphy of the Emanuel Formation (late Tremadocian to early Floian, Early Ordovician) of the Canning Basin, 
and correlation with coeval successions in other regions in South China (Zhen et al., in press a), North China (An et al., 1983) and western 
Newfoundland (Stouge & Bagnoli, 1988). 
Gondwanan plates and terranes. Regional correlation with 
coeval Serratognathus- bearing faunas from the Arafura 
Basin and from China, Korea and Malaysia, defines a distinc¬ 
tive Australasian Province in eastern Gondwana (Zhen et al. 
in Webby et al., 2000) during the latest Tremadocian to early 
Floian (Early Ordovician). Moreover, as the S. bilobatus 
fauna from the Emanuel Formation contains a number of 
pandemic species, it serves as an ideal bridge correlating 
the S. bilobatus faunas in China and the more intensively 
studied Balto-Scandian and North American Mid-continent 
successions. 
Regional geological setting and lithostratigraphy 
The Canning Basin is an intracratonic sag basin, bounded by 
Precambrian rocks of the Kimberley Block to the north and 
the Pilbara Block to the south, occupying about one-sixth of 
Western Australia’s onshore area (Fig. 1). Sparsely inhabited 
and covered largely by flat-topped hills and sand dunes, it is 
dominated by a Palaeozoic-Mesozoic sedimentary succes¬ 
sion more than 15 km in thickness. Extensive geological in¬ 
vestigations have been carried out in the region for more than 
a century (Purcell, 1984), spurred on by its high potential 
for fossil fuel reserves. 
The Early Ordovician Prices Creek Group, representing 
the oldest stratigraphic unit in the basin, is only exposed 
along its northern margin (Lennard Shelf) where it rests 
unconformably on Precambrian basement. This basal 
contact is observable only in drillcore. The Prices Creek 
Group is overlain paraconformably by the Middle Devonian 
(Givetian) Cadjebut Formation (Hocking et al., 1996). 
The group was initially subdivided into a lower Emanuel 
Limestone (subsequently renamed Emanuel Formation) and 
an upper Gap Creek Dolomite (later amended to Gap Creek 
Formation) with a measured thickness of 595 m for the 
Emanuel Formation in the type section along Emanuel Creek 
(Guppy & Opik, 1950; Guppy et al., 1958). Exploration drill 
holes in the area revealed an additional unexposed section 
between the Emanuel Formation and metamorphic rocks of 
the Precambrian basement, comprising a dolomitic interval 
88 m thick underlain by 82 m of arkose (Veevers & Wells, 
1961; Henderson, 1963; McTavish & Leg, 1976; Towner 
& Gibson, 1983). Nicoll et al. (1993) formally named the 
dolomitic unit the Kudata Dolomite and the arkose unit the 
Kunian Sandstone, and revised the Emanuel Formation as 
consisting of limestone intercalated with shale and siltstone 
with a total thickness of 435 m exposed in the type section 
(Fig. 1). 
Regionally the Emanuel Formation conformably overlies 
the Kudata Dolomite and is conformably overlain by the Gap 
Creek Formation of mid-late Floian age (Fig. 2). The basal 
arkose of the Kunian Sandstone was deposited in a major 
transgressive phase flooding the Canning Basin during the 
Tremadocian (Nicoll et al., 1993). This age determination 
was based on the regional tectonic framework and event 
stratigraphy, as well as fossil evidence from the overlying 
Kudata Dolomite, as no fossils were found in the arkose 
unit. The Emanuel Formation was subdivided into three 
informal members (Nicoll et al., 1993). However, in the 
type area, both lower and upper members with intercalated 
shale, siltstone and lim estone (or nodular limestone in the 
upper member) are poorly exposed, whereas the limestone- 
dominated middle member with a thickness of 143 m is 
better exposed forming a more or less continuous section. 
The Emanuel Formation has not only yielded a rich conodont 
fauna, but also trilobites (Legg, 1976; Laurie & Shergold, 
1996a, 1996b), graptolites (Thomas, 1960; Legg, 1976), 
nautiloids (Teichert & Glenister, 1954), gastropods (Gilbert- 
Tomlinson, 1973; Jell et al., 1984; Yu, 1993), brachiopods 
(Brock & Holmer, 2004) and various other invertebrate and 
microfossil groups (Guppy & Opik, 1950; Brown, 1964; 
Schallreuter, 1993a, 1993b). 
