Proportion of total sediment Deposited rock volume (km3) Sedimentary basin Total sediment volume (km3) Average porosity % Rock equivalent (km3) 36-24 Ma 24-8 Ma 8-0 Ma 36-24 Ma 24-8 Ma 8-0 Ma Hanoi Basin 18750 30 13125 0.125 0.635 0.24 1641 8334 3150 Song Hong Basin 750000 20 600000 0.248 0.465 0.285 148800 279000 171000 Paracel Basin 100000 22 78000 0.34 0.3 0.36 26520 23400 28080 Beibu Gulf 87500 33 58625 0.8 0.1 0.1 46900 5863 5863 Total 956250 749750 223861 316597 208093 Grand total 748550 Source Area Width (km) Length (km) Area in Red River drainage (km2) Depth of exhumation (km) Volume of eroded rock (km3) 36-24 Ma 24-8 Ma 8-0 Ma 36-24 Ma 24-8 Ma 8-0 Ma N. Ailao Shan 20 200 4000 3 7 5 12000 28000 20000 S. Ailao Shan 20 250 5000 3 10 2 15000 50000 10000 Day Nui Con Voi 20 270 5400 3 10 2 16200 54000 10800 Song Chay Massif 40 70 2800 3 3 2 8400 8400 5600 Gorges 0 15000 40000 Total 51600 155400 86400 Grand total 293400