The Pho Han Formation is exposed on southernCat Ba Island,Hai Phong Province in northeasternVietnam,and intercalates the Devonian and Carbonif-erous(D-C)boundary(Ta and Doan,2017;Komatsu etal.,2017).The D-C boundary section consists mainlyof limestone beds,numbered from1to167,interca-lated with alternating black organic-rich shales.Thelimestone yields abundant brachiopods,crinoid-stemsand conodonts.Preliminary investigations on strati-graphy(conodont biostratigraphy andδ13C)and se......(论文页数是:1页) ,越南语毕业论文,越南语论文 |