Rugose coral distribution as a test of Devonian palaeogeographic models

Abstract

A data bank, based on stage by stage distributions of 420 rugose coral genera in 25 regions of the world is analysed, mostly by means of Otsuka coefficients, to test an Emsian reconstruction of the world proposed by Scotese. Devonian rugose corals inhabited a narrower range of facies than some other benthic groups, and even without regard to facies, provide a tool for testing geographic reconstructions. Basin dwelling coral genera typically have longer temporal and broader geographic ranges than corals living in shallower environments, and are less suitable for palaeogeographic studies. They are treated separately in this work.For the most part, conclusions drawn from the analysis are either consistent with, or positively supportive of, the Scotese reconstruction. However, large but poorly known rugose coral faunas from Mongolia and the Amur Basin are at about 60~ in the reconstruction, and other well known coral faunas, from Altai-Sayan, are at 45~176In the light of known distributions of both modern corals and Devonian southern hemisphere corals, in all recently proposed palaeogeographic reconstructions, it is questionable that the original latitude of any large northern hemisphere Devonian coral fauna would have exceeded 45 ~ .

Siluro‐Devonian paleomagnetic results from the Tuva Terrane (southern Siberia, Russia): implications for the paleogeography of Siberia

“…Whereas paleomagnetic data [Khramov, 1991;Khramov and Rodionov, 1980] indicate a position of southern Siberia between 40 ø and 50 ø N, the geographical occurrence of climatically sensitive sediments [Scotese and McKerrow, 1990], and the distribution of stromatoporoids [Nestor, 1990], gastropods [Blodgett et al, 1990], rugose corals [Pedder and Oliver, 1990], algae [Poncet, 1990] and miospores [Streel et al, 1990] [ 1998], using the data available, constructed an APWP for Siberia. However, given the sparse and often poorly constrained data set and as discussed by the original authors, the mid-Paleozoic segment of this APWP can only be considered as a first approximation.…”

Lochkovian Rugosa of Nevada

“…Problems associated with the enigmatic benthic faunas of the Balhkash terrane have been discussed previously from the perspectives of both coral (Pedder and Oliver, 1990) and brachiopod workers (Talent et al, 1987;Hou and Boucot, 1990) without firm conclusions. The even greater dissimilarity between Nevada Lochkovian Rugosa of the Old World Realm and those of the Appalachian fold belt, in the Eastern Americas Realm, is best explained by the relatively high Lochkovian latitude of the Appalachian corals, shown as about 30°S on Scotese's reconstruction, and by the barrier effect of a transcontinental arch.…”

“…Its application to Devonian coral faunas, and the bearing such coefficients have on the elucidation of Devonian geography, was most recently discussed by Pedder and Oliver (1990). To optimize results, those authors discarded poorly dated faunas, eliminated long-ranging basin-dwelling genera from their computations, made efforts to ensure that the boundaries of regions compared were rational in light of current plate tectonic doctrine, and above all, attempted to apply uniform generic diagnoses to all faunas and regions.…”

Early Devonian reefs at Reefton, New Zealand: guilds, origin and paleogeographic significance

“…Farther north in Queensland, Early Devonian coral faunas were also present. Pedder & Oliver (1990) consider the latitudinal range for the Early Devonian coral faunas in eastern Australia as 22°S-42°S.…”