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Proposal for Three Middle Permian Foraminiferal Paleobiogeographic Provinces in three stratigraphic settings for Eastern Myanmar
- Eastern part of Myanmar has long been regarded as a part of Sibumasu in the Eastern part of the Cimmerian Continent that drifted northward from Gondwana in Permian time. As a result of some studies on Permian foraminifers in last decade, foraminiferal paleobiogeographic provinces discrimination could be carried out for this region. Here, we proposed three Middle Permian foraminiferal paleobiogeographic provinces in three main stratigraphic settings for the Eastern part of Myanmar. For the purpose, six foraminiferal researches from western part of Eastern Myanmar were accessed and the geographic relationships with the neighbouring Changning-Menglian Belt of West Yunnan and the Inthanon Zone of northern Thailand were considered. The three middle Permian foraminiferal paleobiogeographic provinces from east to west are as follows. The Provinces (I) is designated by potential existence of a belt with PaleoTethyan seamounts; a probable continuation of the Changning-Menglian Belt of the West Yunnan in the north and the Inthanon Zone of northern Thailand in the south. The foraminiferal fauna (Early Carboniferous to Middle-Upper Permian) of the province might be correlable with that of equatorial Paleo-Tethyan regions. Province (2) is characterized by two stratigraphic settings; the first one with middle Permian carbonates resting unconformably upon lower Paleozoic sediments such as Ordovician and Silurian , and the second one with intensely deforming carbonate beds lying conformably over Carboniferous to early Permian clastics. In the Murgabian foraminiferal assemblage, Cimmerian genera are primarily dominant and the Midian ones with both of the Cimmerian and the Paleo-Tethyan affinities but with lower biodiversity. Province (3) is marked by a stratigraphic setting with nearly horizontal or comparatively less deformed carbonate beds resting unconformably over Carboniferous to early Permian clastics. Its fusuline fauna occurs only in the upper part and can be provisionally assigned as Midian. On the other hand, fusuline assemblages similar to those of the Province (2) had been documented from Shazipo Fm. in Xiaoxinzhai section, near Gengma county in the Baoshan Block of West Yunnan and from Thung-Yai area in Peninsular Thailand. Again, Middle Permian fusulines from the Dadongchang Fm. of the Tengchong block of West Yunnan is correlable with those of the Province (3). Here, we concluded that the foraminiferal paleobiogeographic province (2) does extend northward to West Yunnan in Baoshan tectonic block and southward to Thung-Yai area, Peninsular Thailand while the Province (3) extends northward to Tengchong block of West Yunnan.
Tin Tin Latt
Z aw Win
- Conference paper
- The 7th AUN/SEED-Net GeologicaL Engineering Conference (AGEC) & The 2nd AUN/SEED-Net Natural DIsaster Conference (ANDC)