| PDF: | |
| Time: | 1995 |
| Journal: | The editorial board for sedimentary facies and palaeogeography |
| Volumn: | 15 |
| Issue: | 4 |
| Pages: | 14-20 |
| Type: | Other |
| Author: | Pujun Wang,Xiaodi Du,Dongpo Wang |
Abstract: | Situated in the northeast of China(42-49°N,120-128°E),the Songliao Basin is a Cretaceous nearshore continental basin which has been affected significantly by the adjacent marine transgression/regression.The author have recognized in this paper three main marine transgressive records on the maximum lacustrine transgressive sequences of the basin,which occurred separately during the deposition of the third and fourth menbers of the Lower Cretaceous Quantou Formation(Albian),the top of the second and third members pf the Upper Cretaceous Qingshankou Formatin(Turnian),and the first and second members of the Upper Cretaceous Nengjiang Formation(late Santonian-early Campanian).Besides fossil and mineralogical evidences,the marine transgressive geochemical records on the continental basin sequences are;（1）the sharp increase of the heavier isotopes of 34S,18O and13C,and the ratios of 87Sr/86Sr,even up to those of the synchronous normal marine sequences,and(2)the sharp increase of the geochemical indexes for salinity(Sr/Ba),alkalinity(Ca+Mg)/(Si+Al),reducibility (Ni+Zn)/Ga and sulfur flux (S-normalized concentration). The relative sea-level curves have been reconstructed based on the geochemical records cited above using mass balance equation.The mass ratios of marine water to fresh water range between 0 and 15 which are calculated by the “mixing degree” method. |