@article{Hung*_Minh_Hung_Hung_2017, title={New discovery of late early ordovician graptolites and discussion on stratigraphic sequence of paleozoic sediments in the Dinh Ca - Trang Xa Section, Vo Nhai Disctrict, Thai Nguyen Province, Northeast Vietnam}, volume={39}, url={https://vjs.ac.vn/index.php/jse/article/view/9229}, DOI={10.15625/0866-7187/39/1/9229}, abstractNote={<p>Sandstone, quartzitic sandstone rhythmically interbedded with siltstone, calcareous siltstone and cherty shale are largely exposed in the Dinh Ca - Trang Xa area, Vo Nhai District, Thai Nguyen Province, NE Vietnam. In previous studies, they were described as Mo Dong or Than Sa Formations (Middle-Upper Cambrian). The graptolite faunas newly discovered from the Dinh Ca Market - Na Mo - Dong Bo cross section are composed of <em>Expansograptus urbanus </em>(Monsen)<em>,</em><em> Expansograptus abnormis</em> (Hsu),<em> Tetragraptus quadribrachiatus </em>(Hall)<em>, T. approximatus </em>Nicholson<em>, T. pacificus </em>Ruedemann<em>, T. decipiens </em>T.S. Hall<em>, Schizograptus</em> sp<em>., </em>belonging to the <em>quadribrachiatus</em> Biozone, indicating Floian Stage or late Early Ordovician. This serves as the basis for age determination and for establishing new lithostratigraphic units termed as the Dinh Ca Formation (O<sub>1 </sub><em>dc</em>) and the Ba Nhat Member. The stratigraphic sequence of Paleozoic sediments in the Dinh Ca - Trang Xa area is also discussed in this paper.</p><p><strong>References</strong></p> <p>Bergstöm S. M., Löfgren A., and Maletz J., 2004. 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