Late Permian to Middle Triassic radiolarian faunas from northern Thailand

Abstract

Moderately well-preserved Late Permian to Middle Triassic radiolarians are identified in chert beds that occur in the Shan-Thai Block of northern Thailand. These radiolarians are identical to the faunas of the Late Permian Neoalbaillella ornithoformis and N. optima Assemblage Zones and the Triassic Parentactinia nakatsugawaensis and Triassocampe coronata Assemblage Zones reported in chert sequences of Japan. We discovered the radiolarian faunas, apparently indicating Late Permian and Early Triassic ages, in almost continuous sequences of chert and shale exposed in the north of Chiang Mai. The occurrence of these radiolarian faunas provides important data to solve the P/T (Permian/Triassic) boundary in pelagic sequences. Our present discovery also furnishes significant data to reconstruct the paleobiogeography of Mainland Thailand during Late Permian to Middle Triassic times. Fifty species belonging to 35 genera, including three unidentified genera, are investigated taxonomically. Four new species Pseudospongoprunum? chiangdaoensis, Cenosphaera igoi, Cenosphaera? rugosa, and Tlecerina? apsornae are described.

Radiolarian evolution during the latest Permian in South China

“…Significant progress has been made in recent years regarding the biotic extinction pattern of this event and about the survival and recovery after the mass extinction. For Radiolaria, extensive literature is available on the taxonomy and biostratigraphy of Permian and Triassic radiolarians from Europe (Kozur and Mostler, 1994;Kozur et al, 1996), North American Reed, 1992, 1995), Japan (Sashida, 1983;Caridroit and De Wever, 1986;Sashida, 1991;Sugiyama, 1992;Nagai and Mizutani, 1993;Sugiyama, 1997;Kuwahara, 1999;Kuwahara and Yao, 2001;Xia et al, 2004), northeastern Russia (Bragin, 1991;Vishnevskaya, 1997), China (Wang et al, 1994;Wu et al, 1994;Feng et al, 1996;Yao and Kuwahara, 1997;Feng et al, 1998;Kuwamura, 1999, 2000;Feng et al, 2000;Feng et al, 2001;Feng and Gu, 2002;Kuwahara et al, 2003), Thailand (Sashida and Igo, 1992;Caridroit, 1993;Sashida et al, 1998Sashida et al, , 2000a, Philippines (Cheng, 1989), and New Zealand (Kamata et al, 2003(Kamata et al, , 2005. Some paleontologists have attempted to analyze and elucidate the evolution of radiolarian faunas across the Permian-Triassic transition and found that about 80% of radiolarian taxa became extinct by the endPermian and that some Paleozoic taxa have been observed to survive into the Mesozoic (Kozur and Mostler, 1982;Sashida, 1983;Baumgartner, 1984;Yeh, 1987;…”

Differential severity of Permian–Triassic environmental changes on Tethyan shallow-water carbonate platforms

“…8.3) with an elongate test and a two-layered wall (Vachard et al, 2002) and the radiolarian Entarctinia sp. with a simple single-layered shell (Sashida et al, 2000;He et al, 2005). The radiolarian species is indeterminable because of poor preservation.…”

Geochemical constraints on the depositional environment of Upper Devonian radiolarian cherts from Loei, north-eastern Thailand

“…This first report on geochemistry of cherts in Thailand indicates that the main Palaeotethys should be located further to the west of Nan-Uttaradit Suture. Beside the Triassic cherts, there are Devonian, Carboniferous and Permain radiolarian cherts which have been reported in northern, western, southern and north-eastern Thailand (e.g., Caridroit, 1993;Sashida and Igo, 1999;Sashida et al, 2000;Sashida and Salyapongse, 2002;Feng et al, 2002, 2004, 2005, Thassanapak et al, 2007.…”