Page 305 - Introduction to Paleobiology and The Fossil Record

292 INTRODUCTION TO PALEOBIOLOGY AND THE FOSSIL RECORD

small favositid and
heliolitid tabulate corals
clusters of crinoids

small stromatoporoids

generalist brachiopods
and molluscs

fasciculate rugose corals
(a)
large, platy to domed favositid and
heliolitid tabulate corals
diverse crinoids

cerioid, astraeoid,
thamnasterioid and
aphroid rugose corals massive stromatoporoids

specialist, small to large brachiopods
and mollusks

(b)
Figure 11.34 Pioneer (a) and climax (b) reef communities in Silurian and Devonan reef systems. (From
Copper, P. 1988. Palaios 3.)

long and up to 300 km wide and visible from facies can be mapped in considerable detail,
space. It is a long-lived structure dating back as the Windjana Gorge dissects the near-
to the Miocene. The reef extends from 9˚ to horizontal strata of the northern margin of
25˚ south and comprises many multicolored the Canning Basin (Fig. 11.35). An unbedded
scleractinian corals together with many other core of calcareous algae, corals and stromato-
invertebrates and calcareous algae. The fore- poroids sheltered a back-reef and lagoonal
reef deposits tumble eastwards into the environment packed with calcareous algae,

western Pacific; landward back-reef lagoons corals, stromatoporoids and crinoids together
are developed against eastern Australia. Can with brachiopods, bivalves, cephalopods and
such reef constellations really be recognized gastropods. In front the fore-reef was steep
in the fossil record? On the adjacent continent and littered by reef talus. However, during the
the Upper Devonian rocks of the Canning Late Devonian extinction event, at the end
Basin contain fossil barrier reefs dominated of the Frasnian, associations dominated by
by calcareous algae and tabulate and rugose rugose and tabulate corals together with stro-
corals together with stromatoporoids and matoporoids disappeared; this type of reef
microbiolites. The reef and its associated ecosystem never recovered.