| To assign the interbedded sedimentary strata to the correct system it is, however, necessary to incorporate biostratigraphic and petrographic data. |
| These are accompanied by much smaller sets of petrographic thin sections from Mesozoic and Cenozoic carbonate strata. |
| It is noteworthy that this map closely matches the petrographic contours of the geological map. |
| They conducted Xray diffraction and petrographic analysis of thin sections from a vessel suspected to have originated in the Caddoan region. |
| The sediments of the Grensen Formation are barren of all organic material and hence must be dated using radiometric and petrographic evidence alone. |
| Various combinations of these processes are invoked to account for the range of geochemical and petrographic features in tale-alkaline continental margin volcanic arc suites. |
