New Permo-Carboniferous geochemical data from central Thailand: implication for a volcanic arc model

Current ideas and models of geotectonic reconstructions of Southeast Asia are reviewed and new data on Late Carboniferous through Middle Permian tuffites and sills from central Thailand are presented in the light of the problems of Southeast Asian palaeogeography. The volcanic rocks of quartz-keratophyric to spilitic composition are associated with platform carbonates and deep basin sediments. Their geochemistry and the character of the accompanying sediments suggest the existence of a Late Palaeozoic volcanic arc separating a subduction zone in the west from a back arc basin to the east. The geotectonic frame of Southeast Asia is explained in terms of repeated accretion of volcanic arcs by the Late Palaeozoic subduction zone along the northern Tethys margin

Permian fusulinacean faunas of Thailand — event controlled evolution

The evolution of the fusulinacean faunas of Thailand during Permian times is controlled by bioevents. The first bioevent happened in the upper Lower Permian and is characterized by the disappearance of the Arctic-Tethyan elements. This bioevent can be correlated with the closure of the Urals and a worldwide regression. The second bioevent happened at the boundary Middle/Upper Permian to lower Upper Permian (Midian). It is characterized by the extinction of approximately 90 % of the fusulinaceans. This bioevent is controlled by the orogenic evolution of the Kunlun and the Petchabun fold and thrust belt, which again led to a worldwide regression. The third bioevent happened at the boundary Permian/Triassic. It is characterized by the final extinction of the fusulinaceans and might be controlled by the isostatic uplift of the newly formed mountain belt

Sponge assemblage of some Upper Permian reef limestones from Phrae province (Northern Thailand)

The sponge fauna of uppermost Permian reef or reefal limestones of the Phrae province in northern Thailand include representatives of hexactinellida, sclerospongea,"sphinctozoans", and "inozoans". The "sphinctozoans" and "inozoans"are described in detail. Following taxa are new:"Sphinctozoans": Phraethalamia tubulara n. gen., n. sp., Ambithalamia pérmican. gen., n. sp."Inozoans": Bisiphonella tubulara n. sp., Solutossaspongia crassimuralis n.gen., n. sp.The genus name Belyaevaspongia nom. nov. is proposed for PolysiphonellaBelyaeva, 1991 (in Boiko et al., 1991), non Polysiphonella Russo, 1981

Long-lived Paleotethyan pelagic remnant inside Shan-Thai Block: Evidence from radiolarian biostratigraphy

Newly identified radiolarians from ribbon chert in the Mae Hong Son-Mae Sariang area, northwestern Thailand covered Early Carboniferous, Late Permian, and Middle-Late Triassic in age, which indicate that there was a pelagic basin during the Late Paleozoic and Triassic in this region together with the published radiolarian biostratigraphic data. This basin is joined with the Chiang Dao and Changning-Menglian oceanic basins, which represent the main oceanic basin of Paleotethyan Archipelago Ocean. The main oceanic basin was situated in the traditional "Shan-Thai Block". Therefore, "the Shan-Thai Block" was not a single block during that stage, but composed of the Paleotethyan Ocean and two continental terranes that affiliated to Gondwana and Cathysian domains respectively

Correlation of Triassic stratigraphy between the Simao and Lampang-Phrae Basins: implications for the tectonopaleogeography of Southeast Asia

Based on our extensive fieldwork in southwestern Yunnan and northern Thailand, followed by detailed stratigraphic and paleontological studies, we propose that the Triassic Simao Basin in Yunnan can be correlated with the Triassic Lampang-Phrae Basin in Thailand. Strata equivalent to those in the southern Lancangjiang sub-basin have not been identified in northern Thailand. We consider that during the Triassic the Simao and the Lampang-Phrae Basins belonged to the same tectonopaleogeographic unit. The orogenic belt to the east of this unit includes the Nan-Uttaradit and Ailaoshan sutures. The 'Shan-Thai Block' in northern Thailand, can be divided from east to west into the Sukhothai, the Inthanon, and the Shan terranes. According to tectonopaleogeographic correlation, our results support the idea that the Sukhothai Terrane, including the Lampang-Phrae Basin, belongs to the Cathaysian domain and not to Gondwana domain, and that the geosuture corresponding to the Changning-Menglian Suture in Yunnan must lie to the west of the Sukhothai Terrane in Thailand. © 2005 Elsevier Ltd. All rights reserved

Early Carboniferous radiolarians from north-west Thailand: Palaeogeographical implications

Moderately well-preserved radiolarian assemblages are described from bedded cherts south of Mae Hong Son, north-west Thailand. Twenty species and subspecies are identified, including one new species (Archocyrtium sashidai Feng sp. nov.). The assemblages belong to the middle Early Carboniferous Albaillella indensis and Eostylodictya rota zones. The new data suggest that there was a pelagic basin between the Shan-Thai terrane and Gondwana during the Early Carboniferous. This implies, contrary to previous interpretations, that the Shan-Thai terrane had already rifted apart from Gondwana during the Early Carboniferous

Comparison of the Paleozoic sequences from the Padaukpin area (Northern Shan States, Union of Myanmar) and the Baoshan region (Western Yunnan, P. R. of China)

The Paleozoic sequences of the Padaukpin area of the Northern Shan States (Union of Myanmar) and the Baoshan region in Western Yunnan (P. R. of China) are compared. They show many similarities. A hiatus in sedimentation during the Carboniferous is developed in both regions and is therefore of regional importance. The Middle Devonian rugose coral fauna of both regions are typical for the Old World Faunal Realm and especially corals from the Padaukpin area (Northern Shan States), show strong affinities to the Rhenish faunas from the German Eifel mountains. While the "pebbly mudstones" of Early Permian age from the Baoshan region are usually discussed in the literature as glaciomarine deposits, similar strata in the Shan States are described as oligomictic conglomerate facies at the base of the Thitsipin Limestone Formation.Die paläozoischen Schichtfolgen des Gebietes von Padaukpin in den Nördlichen Shan Staaten (Union von Myanmar) und der Baoshan Region in West Yunnan (Volksrepublik China) werden verglichen. Sie zeigen eine große Übereinstimmung. Eine Schichtlücke im Karbon ist in beiden Gebieten ausgebildet; sie ist deshalb von regionaler Bedeutung. Die mitteldevonischen rugosen Korallenfaunen beider Regionen sind typisch für den Old World Realm und insbesondere die Fauna von Padaukpin (Nördliche Shan Staaten) zeigt Affinitäten zu den Rheinischen Faunen aus der Eifel. Während die unter-permischen "pebbly mudstones" der Baoshan Region in der Literatur im Allgemeinen als glaziomarine Ablagerungen diskutiert werden, werden ähnliche Sedimente in den Shan Staaten als oligomikte Konglomeratfazies an der Basis der Thitsipin Limestone Formation beschrieben