Radiation and extinction patterns in Permian floras from North China as indicators for environmental and climate change

Abstract

Permian continental sequences from North China contain previously unrecognized episodes of plant radiation and elevated extinction. The earliest extinction, in the Lower Shihhotse Formation (Roadian, Guadalupian), records a 45% floral species loss and is tentatively correlated with global extinctions amongst dinocephalian reptiles. Two younger extinctions are dated by correlating the Illawara Reversal and palaeomagnetic polarity sequences from Shanxi Province against global palaeomagnetic history. Missing data from the Shanxi sequence are evaluated using a novel approach estimating likely maximum and minimum sequence changes that provide age estimates for post-Illawara events in North China. The second extinction in the middle Upper Shihhotse Formation is more significant and is dated to the mid-Capitanian, with a loss of 56% of plant species coinciding with two phases of volcanism of the Emeishan Large Igneous Province in South China, previously linked to the mid-Capitanian marine mass extinction. The youngest extinction in the upper Upper Shihhotse Formation (late Capitanian to mid-Wuchapingian) is catastrophic and represents the end of range in the sequence. Changes in sedimentary facies suggest it to be related to global climatic warming and drying. Other viable causal mechanisms for the extinction episodes include plate motion and collision, global climate change, volcanism and biological competition.

When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa

“…[7,11,13,[38][39][40]). The new age of approximately 260 Ma for the top of the Tapinocephalus AZ in South Africa is consistent with a further temporal link between Emeishan volcanism and tetrapod extinctions.…”

“…In the terrestrial realm, at least one extinction event among plant species has been identified in the Capitanian Upper Shihhotse Formation of Northern China, suggesting the loss of at least 56% of plant species within this stage [13]. Unfortunately, the age estimates for this sequence rely on palaeomagnetism and missing data within the stratigraphic profile has led to high uncertainty in their correlation with the marine timescale.…”

Evidence of widespread wildfires in a coal seam from the middle Permian of the North China Basin

“…In the middle Permian there were also some local volcanic eruptions in north China (Zhao et al, 2010). The collision of the North China block with Siberia during the Permian and the Sino-Mongolian seaway closing during the middle Permian resulted in abundant volcanism along the northern margin of north China during this period (Zhao et al, 2010;Stevens et al, 2011). Therefore, these middle Permian eruptions in north China could also have ignited wildfires.…”

“…The pollutant discharge and the concomitant temperature increase might have affected floral growth thereafter. According to Stevens et al (2011), three floral extinction events in north China in the lower Shihhotse Formation (upper-middle Permian Period), which directly overlies the Shanxi Formation, have been found. Therefore, we may deduce that enormous amount of harmful gases released and increased local temperatures could be one of the reasons for the floral extinctions that occurred after the time of the Shanxi Formation.…”

“…High concentrations of inertinite have been found at one section of Dongpang coal mine in the middle Permian coal from the North China Basin by Sun et al (2002); however, they did not recognize widespread wildfire and its significance. Furthermore, three floral extinction events in north China in the upper middle Permian Period (the Xiashihezi Formation; formerly the Low Shihhotse Formation) were reported by Stevens et al (2011).…”