PALAEOZOIC HISTORY OF THE ST. VINCENT GULF REGION, SOUTH AUSTRALIA

1972 ◽  
Vol 12 (1) ◽  
pp. 9 ◽  
Author(s):  
William J. Stuart ◽  
A.T. von Sanden
Keyword(s):  
Lower Cambrian ◽  
Regional Metamorphism ◽  
South Australia ◽  
Lower Permian ◽  
Gulf Region ◽  
Middle Cambrian ◽  
Upper Proterozoic ◽  
Marginal Areas ◽  
Major Fault ◽  
Yorke Peninsula

The St. Vincent Gulf Region comprises portions of the Gawler Craton and Adelaide Geosyncline. It extends from Yorke Peninsula and a portion of Investigator Strait (within the craton) to the Mt. Lofty — Kangaroo Island fold belt (inclusive). An area of potential hydrocarbon accumulation exists in a marginal area of the geosyncline adjacent to the craton.After latest Precambrian deformation of Proterozoic strata, Lower Cambrian deposition commenced with transgressive arkoses, overlain by carbonates. The upper portion of the carbonates near or on the craton grade eastwards into mudstones in the geosyncline proper. A major retreat of the sea from marginal areas of the craton and geosyncline occurred during late Lower Cambrian time. The exposed land mass constituted a source for clastics deposited in the remainder of the geosyncline, which was undergoing strong downwarping movements. Intercalated carbonates and clastics of latest Lower Cambrian and Middle Cambrian age document return of the sea to the craton.Deposition in the geosyncline probably terminated during Middle Cambrian time, with pronounced earth movements and regional metamorphism culminating during Ordovician time. The Palaeozoic and Proterozoic rocks are unconformably overlain by Lower Permian and Cainozoic sediments.Three major fault patterns can be recognized in the region. Within most of the western portion, the fault pattern is similar to that of the Gawler Craton. Two later patterns of faulting in the remainder of the region evolved during Upper Proterozoic-Cambrian and Cambro-Ordovician times respectively, as the consequence of pronounced folding. Episodic movements of blocks bounded by faults in the western and northwestern portions of the region were the result of strong compressional forces directed towards the craton. Weaker earth movements also occurred during Lower Permian-Eocene time rejuvenating some of the old structures.

Cambrian Lagerstätten: their distribution and significance

1985 ◽  
Vol 311 (1148) ◽  
pp. 49-65 ◽  
Keyword(s):  
British Columbia ◽  
Special Reference ◽  
Community Ecology ◽  
Lower Cambrian ◽  
South Australia ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
Exceptional Preservation ◽  
Biotic Diversity

The geological setting, biotic diversity and taphonomy of Cambrian soft-bodied Lagerstätten are reviewed with special reference to the Lower Cambrian Emu Bay Shale (South Australia) and Kinzers Formation (Pennsylvania), and the Middle Cambrian Stephen Formation (Burgess Shale and adjacent localities, British Columbia). Brief mention is made also of a number of more minor occurrences in the U.S.A., China and Spain. Exceptional preservation in the Upper Cambrian is discussed by K. J. Müller (this symposium). These soft-bodied Lagerstätten afford a series of special insights into the nature of Cambrian life. Emphasis is laid on the information they provide with regards (i) levels of diversity and the proportion of skeletized taxa; (ii) the origin and relative success of bodyplans; (iii) community ecology and evolution.

Shelly fossils from the Early Cambrian (Toyonian) Wirrealpa, Aroona Creek, and Ramsay Limestones of South Australia

1993 ◽  
Vol 67 (5) ◽  
pp. 758-787 ◽  
Author(s):  
Glenn A. Brock ◽  
Barry J. Cooper
Keyword(s):  
Sequence Stratigraphy ◽  
Siberian Platform ◽  
South Australia ◽  
Early Cambrian ◽  
Middle Cambrian ◽  
Marine Transgression ◽  
Small Shelly Fossils ◽  
Flinders Ranges ◽  
Yorke Peninsula

Small shelly fossils from the Wirrealpa and Aroona Creek Limestones, Flinders Ranges, and the temporally equivalent Ramsay Limestone, Yorke Peninsula, South Australia, are described and assessed. These formations, deposited during a widespread marine transgression, have traditionally been assigned an early Middle Cambrian age based on lateral facies relationships, lithostratigraphic interpretation, and age diagnostic trilobites. However, new data from regional sequence stratigraphy and mounting paleontological evidence suggest that a late Early Cambrian age (equivalent to the Toyonian Stage from the Siberian Platform) is more appropriate for these units. Twenty-four taxa, including a number of problematica, poriferans, coeloscleritophorans, palaeoscolecidans, “conodontomorphs,” hyolithelminthes, hyoliths, mollusks, and inarticulate brachiopods, are reported herein; many of these have not previously been reported from the Cambrian of South Australia. The enigmatic Chalasiocranos exquisitum n. gen. and sp., known from disarticulated tuberculate cone-shaped phosphatic sclerites, and Protomelission gatehousei n. gen. and sp., a problematic, perhaps colonial organism, known from phosphatic plates, are especially notable. The genus Kaimenella is formally included in the Palaeoscolecida, and two species (including K. dailyi n. sp.) are recognized.

PALEOENVIRONMENTAL AND TAPHONOMIC IMPLICATIONS FOR LOWER CAMBRIAN PHOSPHATIC HARDGROUNDS FROM SOUTH AUSTRALIA

2020 ◽  
Author(s):  
Sarah M. Jacquet ◽  
◽  
April A. Miller ◽  
Laura Speir ◽  
Tara Selly ◽  
...  
Keyword(s):  
Lower Cambrian ◽  
South Australia

Early Paleozoic Hyolitha from North America: reexamination of Walcott's and Resser's type specimens

1988 ◽  
Vol 62 (2) ◽  
pp. 218-233 ◽  
Author(s):  
John Mark Malinky
Keyword(s):  
North America ◽  
Lower Cambrian ◽  
Type Species ◽  
New Genus ◽  
Early Paleozoic ◽  
Type Specimens ◽  
Middle Cambrian ◽  
Upper Cambrian ◽  
New Family ◽  
The Family

Concepts of the family Hyolithidae Nicholson fide Fisher and the genera Hyolithes Eichwald and Orthotheca Novak have been expanded through time to encompass a variety of morphologically dissimilar shells. The Hyolithidae is here considered to include only those hyolithid species which have a rounded (convex) dorsum; slopes on the dorsum are inflated, and the venter may be flat or slightly inflated. Hyolithes encompasses species which possess a low dorsum and a prominent longitudinal sulcus along each edge of the dorsum; the ligula is short and the apertural rim is flared. The emended concept of Orthotheca includes only those species of orthothecid hyoliths which have a subtriangular transverse outline and longitudinal lirae covering the shell on both dorsum and venter.Eighteen species of Hyolithes and one species of Orthotheca from the Appalachian region and Western Interior were reexamined in light of more modern taxonomic concepts and standards of quality for type material. Reexamination of type specimens of H. similis Walcott from the Lower Cambrian of Newfoundland, H. whitei Resser from the Lower Cambrian of Nevada, H. billingsi Walcott from the Lower Cambrian of Nevada, H. gallatinensis Resser from the Upper Cambrian of Wyoming, and H. partitus Resser from the Middle Cambrian of Alabama indicates that none of these species represents Hyolithes. Hyolithes similis is here included under the new genus Similotheca, in the new family Similothecidae. Hyolithes whitei is designated as the type species of the new genus Nevadotheca, to which H. billingsi may also belong. Hyolithes gallatinensis is referred to Burithes Missarzhevsky with question, and H. partitus may represent Joachimilites Marek. The type or types of H. attenuatus Walcott, H. cecrops Walcott, H. comptus Howell, H. cowanensis Resser, H. curticei Resser, H. idahoensis Resser, H. prolixus Resser, H. resseri Howell, H. shaleri Walcott, H. terranovicus Walcott, and H. wanneri Resser and Howell lack shells and/or other taxonomically important features such as a complete aperture, rendering the diagnoses of these species incomplete. Their names should only be used for the type specimens until better preserved topotypes become available for study. Morphology of the types of H.? corrugatus Walcott and “Orthotheca” sola Resser does not support placement in the Hyolitha; the affinities of these species are uncertain.

Hosts of the exotic ornate kangaroo tick, Amblyomma triguttatum triguttatum Koch, on southern Yorke Peninsula, South Australia

2007 ◽  
Vol 101 (5) ◽  
pp. 1323-1330 ◽  
Author(s):  
Helen P. Waudby ◽  
Sophie Petit ◽  
Bruce Dixon ◽  
Ross H. Andrews
Keyword(s):  
South Australia ◽  
Yorke Peninsula

Articulated halkieriids from the Lower Cambrian of North Greenland and their role in early protostome evolution

1995 ◽  
Vol 347 (1321) ◽  
pp. 305-358 ◽  
Keyword(s):  
Body Size ◽  
Molecular Biology ◽  
Lower Cambrian ◽  
Burgess Shale ◽  
Internal Anatomy ◽  
Middle Cambrian ◽  
Functional Consequence ◽  
Primitive State ◽  
North Greenland

Articulated halkieriids of Halkieria evangelista sp. nov. are described from the Sirius Passet fauna in the Lower Cambrian Buen Formation of Peary Land, North Greenland. Three zones of sclerites are recognizable: obliquely inclined rows of dorsal palmates, quincuncially inserted lateral cultrates and imbricated bundles of ventro-lateral siculates. In addition there is a prominent shell at both ends, each with radial ornamentation. Both sclerites and shells were probably calcareous, but increase in body size led to insertion of additional sclerites but marginal accretion of the shells. The ventral sole was soft and, in life, presumably muscular. Recognizable features of internal anatomy include a gut trace and possible musculature, inferred from imprints on the interior of the anterior shell. Halkieriids are closely related to the Middle Cambrian Wixaxia , best known from the Burgess Shale: this clade appears to have played an important role in early protostome evolution. From an animal fairly closely related to Wixaxia arose the polychaete annelids; the bundles of siculate sclerites prefigure the neurochaetae whereas the dorsal notochaetae derive from the palmates. Wixaxia appears to have a relic shell and a similar structure in the sternaspid polychaetes may be an evolutionary remnant. The primitive state in extant polychaetes is best expressed in groups such as chrysopetalids, aphroditaceans and amphinomids. The homology between polychaete chaetae and the mantle setae of brachiopods is one line of evidence to suggest that the latter phylum arose from a juvenile halkieriid in which the posterior shell was first in juxtaposition to the anterior and rotated beneath it to provide the bivalved condition of an ancestral brachiopod. H. evangelista sp. nov. has shells which resemble those of a brachiopod; in particular the posterior one. From predecessors of the halkieriids known as siphogonuchitids it is possible that both chitons (polyplacophorans) and conchiferan molluscs arose. The hypothesis of halkieriids and their relatives having a key role in annelid—brachiopod—mollusc evolution is in accord with some earlier proposals and recent evidence from molecular biology. It casts doubt, however, on a number of favoured concepts including the primitive annelid being oligochaetoid and a burrower, the brachiopods being deuterostomes and the coelom being an archaic feature of metazoans. Rather, the annelid coelom arose as a functional consequence of the transition from a creeping halkieriid to a polychaete with stepping parapodial locomotion.

Sign in / Sign up

Export Citation Format

Share Document