Paleomagnetic insights into the Cambrian biogeographic conundrum: Did the North China craton link Laurentia and East Gondwana?

Abstract

Redlichiid trilobite and small shelly fossils indicate strong ties of the North China craton (NCC) to Gondwana during the early Cambrian, while recent discoveries of the characteristic fossils of Laurentia in Wuliuan shales in the eastern NCC imply its possible connection with Laurentia during the middle Cambrian. Here we report a new paleomagnetic pole at 31.8°S, 140.4°E (radius of 95% confidence cone of paleomagnetic pole, A95, = 5.3°), obtained from the Wuliuan (ca. 505 Ma) Hsuchuang Formation, by averaging our new data and existing virtual geomagnetic poles acquired from different parts of the NCC. A positive regional tilt test and the presence of geomagnetic reversals demonstrate that the remanence was primary. The paleomagnetic data permit placing the NCC near 20°N between Laurentia and Australia at ca. 505 Ma, suggesting that the NCC may have played the role of biogeographic link between East Gondwana and Laurentia in the middle Cambrian. Low-latitudinal westward ocean currents may have facilitated faunal migrations from Laurentia to East Gondwanan blocks via the NCC as well as the newly formed tectono-paleogeographic archipelago, which likely further enhanced biological exchange in the late Cambrian.

The first systematic description of Cambrian fossils from Myanmar: Late Furongian trilobites from the southern part of the Shan State and the early Palaeozoic palaeogeographical affinities of Sibumasu

“…However, palaeomagnetic data for the Cambrian of Baoshan (Li et al, 2004, Fig. 4) suggests a low latitude Cambrian setting, similar to that for North China (Huang et al, 1999(Huang et al, , 2000Zhao et al, 2020), South China, and Australia (Li et al, 2004, Fig. 4) during that period, although the reliability of these data has been queried (Burrett et al, 2014).…”

First Report of Small Shelly Fossils from the Cambrian Miaolingian Limestones (Zhangxia and Hsuzhuang Formations) in Yiyang County, Henan Province of North China

“…Besides, North China Platform also has a relatively high similarity with Laurentia, especially in the brachiopod fauna. As proposed by Zhao et al [48], NCP may link the Laurentia and Australia promoting the exchange of faunas during the middle Cambrian. However, further studies of middle Cambrian faunas from North China are required to determine the more precise palaeogeographic location of NCP.…”

“…Both palaeomagnetic insights and fossil correlation aspects (especially trilobites, brachiopods and other SSFs) have been used to understand the palaeogeographic location of the NCP, during the latest Ediacaran and the early to middle Cambrian [8,26,48,49]. Previous studies point a relatively close palaeogeographic location between the independent NCP continent and the East Gondwana, especially South Australia [8,34].…”

The first Middle Ordovician and Gondwanan record of the cincinnaticrinid crinoidOhiocrinus byeongseonin. sp. from South Korea: biostratigraphy, paleobiogeography, and taphonomy

“…It is of interest that they interpreted the relationship as suggesting a possible, although unsubstantiated, paleobiogeographic connection between the two areas. In addition, a recent paleomagnetic study proposed a radical view about the position of North China, including the Korean Peninsula, during middle Cambrian (Zhao et al, 2021). They positioned North China between Laurentia and East Gondwana, including Australia, and interpreted that it perhaps acted as a paleobiogeographic link.…”