Significance of FRST and LST discrimination in Sequence Stratigraphic studies, examples from Asmari and Qum formations

Category Sedimentology
Group GSI.IR
Location The 24 Symposium of Geosciences
Holding Date 18 August 2007


Discrimination of a sequence and its components (system tract, parasequence, parasequence set) is essential in sequence stratigraphic studies. More detailed description of the sequence and its components will provide greater information on the relative sea level change analysis of the basin under investigation. This requires greater attention where discrimination of the system tracts has greater priority. Determination of a system tract on the sea level curve should be carried out based on its position on the sea level curve, stratal surfaces, the nature of constituent facies, the ratio of accommodation to sediment supply, stacking pattern of the constituent parasequences, and geometry. In this regard a given sequence is divided in to 4 system tracts known as forced regressive, lowstand, transgressive, and highstand system tracts (FRST, LST, TST, and HST). The system tracts show various characteristics which reflect various chemical, physical and biological conditions in their deposition site. Occurrence of the FRST in the forms of erosional surface and karstification and scarcity of the FRST sediments in geological records are the main causes for ignorance of this system tract in some studies. This paper discus the requirements of the FRST from LST separation in sequence stratigraphic studies by providing examples from Asmari and Qum formations.

tags: QAZVIN