North China craton: The conjugate margin for northwestern Laurentia in Rodinia

Abstract

In the Rodinia supercontinent, Laurentia is placed at the center because it was flanked by late Neoproterozoic rifted margins; however, the conjugate margin for western Laurentia is still enigmatic. In this study, new paleomagnetic results have been obtained from 15 ca. 775 Ma mafic dikes in eastern Hebei Province, North China craton (NCC). Stepwise thermal demagnetization revealed a high-temperature component, directed northeast or southwest with shallow inclinations, with unblocking temperatures of as high as 580 °C. Rock magnetism suggests the component is carried by single-domain and pseudo-single-domain magnetite grains. Its primary origin is supported by a positive reversal test and regional remanence direction correlation test, and the paleomagnetic pole (29.0°S, 64.7°E, A95 = 5.4°) is not similar to any published younger poles of the NCC. Matching the late Mesoproterozoic to early Neoproterozoic (ca. 1110–775 Ma) apparent polar wander paths of the NCC and Laurentia suggests that the NCC could have been the conjugate margin for northwestern Laurentia in Rodinia, rather than sitting off the northeast coast of the main Rodinian landmass. Geological data indicate that breakup of the NCC and Laurentia occurred between ca. 775 and 720 Ma.

The late Mesoproterozoic to early Neoproterozoic Grenvillian orogeny and the assembly of Rodinia: Turning point in the tectonic evolution of Laurentia

“…In the reconstruction, Laurentia is conjoined with Siberia (following Evans et al, 2016), North China (following Ding et al, 2021) and Australia+East Antarctica (following Swanson-Hysell et al, 2012). We implement the model that, throughout the late Paleoproterozoic and the majority of the Mesoproterozoic, Baltica was in a configuration where there was a tight fit between northern Norway and the Kola Peninsula of Russia with the east margin of Greenland (Gower et al, 1990).…”

New Paleomagnetic Insights Into the Neoproterozoic Connection Between South China and India and Their Position in Rodinia

“…For other continents in the reconstruction, their positions are according to Ding et al. (2021). (b) Zoom out of the SCC‐India tectonic entity showing the key geological evidence.…”

“…775 Ma Gunbarrel large igneous province in Laurentia (Eyster et al., 2020, and references therein) and the pole of the ca. 775 Ma mafic dykes in the north China craton (NCC; Ding et al., 2021), providing an opportunity of direct comparison between these paleocontinents. The comparison demonstrates that the mid‐to‐high latitudinal SCC‐Indochina‐India landmass was far away from the equatorial Laurentia and the low latitudinal NCC, as well as the major continents located close to Laurentia in some prevailing Rodinia models (Figure 3a).…”

The Precambrian paleogeography of Laurentia

“…The hypothesized connection between Siberia and Laurentia is implemented following Evans et al (2016b) who interpret this relationship as persistent from 1.7 to 0.7 Ga. The reconstruction of North China to Laurentia follows Ding et al (2021). The omission of South China from Rodinia follows Park et al (2021b).…”

“…The latest Mesoproterozoic to earliest Neoproterozoic pole path of the North China craton includes a swath of paleomagnetic poles with a similar arc length to the Keweenawan Track to Grenville Loop of Laurentia's APWP (Zhao et al, 2019;Ding et al, 2021;Zhang et al, 2021). While the chronostratigraphic age constraints on these North China poles are much looser than those from Laurentia, Zhao et al (2019) proposed that the North China poles can be aligned with the Keweenawan Track to reconstruct North China as being conjoined to the northwestern margin of Laurentia from prior to ca.…”