A palaeomagnetic and palaeobiogeographical perspective on latest Neoproterozoic and early Cambrian tectonic events

Abstract

During the latest Neoproterozoic to Mid-Cambrian time (580-505 Ma ago), the Earth underwent significant changes in palaeogeography that included rifting of a possible supercontinent and the near simultaneous formation of a second, slightly smaller supercontinent. It is against this tectonic backdrop that the Cambrian radiation occurred. Although the general tectonic setting during this interval is fairly well constrained, models of the exact palaeogeography are controversial because of the lack of reliable palaeomagnetic data from some of the continental blocks. Palaeogeographical models based on palaeomagnetic data range from a high-latitude configuration for most continents, to a low-latitude configuration for most continents, or to rapid oscillations in continental configurations triggered by inertial changes within the planet. Palaeobiogeographical data can also be used to help constrain palaeogeographical models. To this end we use vicariance patterns in olenellid trilobites to determine their compatibility with three end-member palaeogeographical models derived from palaeomagnetic data for the Neoproterozoic and early Cambrian. The most congruent palaeogeographical model with respect to the palaeobiogeographical data described herein is the high-latitude configuration for most continents. Those palaeomagnetic models that predict inertial interchange true polar wander or multiple episodes of true polar wander differ significantly from the results from palaeobiogeography. The low-latitude palaeogeographical models also differ from the results from palaeobiogeography, but this may partly arise because of a lack of palaeomagnetic and palaeobiogeographical data from many parts of present-day South America and Africa.

Sulfur and strontium isotopic compositions of carbonate and evaporite rocks from the late Neoproterozoic–early Cambrian Bilara Group (Nagaur-Ganganagar Basin, India): Constraints on intrabasinal correlation and global sulfur cycle

“…Palaeogeographic reconstructions for this time by Gorin et al (1982), McKerrow et al (1992), and Meert and Lieberman (2004) support an equatorial position of the northern part of Gondwanaland.…”

“…Enhanced burial of reduced sulfur, such as pyrite, would shift the marine sulfate sulfur isotopic signal towards enriched values, whereas enhanced pyrite weathering and a concomitant fluvial flux of dissolved sulfate would result in a decrease in δ 34 S (Kampschulte and Strauss, 2004). The geochemical changes recorded across the terminal Neoproterozoic and its transition into the early Cambrian have been linked to geological (rearrangement of landmasses: e.g., McKerrow et al, 1992;Meert and Lieberman, 2004) and biological (evolutionary: e.g., Glaessner, 1984;Conway Morris, 1987; changes.…”

Species’ Geographic Distributions Through Time: Playing Catch-up with Changing Climates

“…might be seen as fairly unlikely to have influenced major features of species' distributions. However, such changes have been documented to have had significant effects on species' distributions and phylogenetic patterns in the distant geological past, for example, the Cambrian and the Devonian (Lieberman and Eldredge 1996;Lieberman 2000bLieberman , 2003Meert and Lieberman 2004;Rode and Lieberman 2005). Even since the Late Pleistocene, some Earth regions have shown substantial uplift or subsidence (Harff et al 2007), and major Earth features, such as the Andean mountain chain, have arisen relatively recently (Hartley 2003), creating important new distributional opportunities and barriers for species and biotas.…”

A comparison of the biological, geological events and environmental backgrounds between the Neoproterozoic-Cambrian and Permian-Triassic transitions

“…The re-assembly witnessed the appearances of multicellular algae, biodiversification of metazoans and the Cambrian Explosion. The Gondwana played a critical role in palaeobiogeographical and palaeogeographical re-configuration during the entire Palaeozoic [71].…”