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Biostratigraphy and Paleoecology of Maastrichtian Sediments in the Zagros Basin, Iran
Author(s) -
SHIRAZI Mahnaz Parvaneh Nejad,
SHAMS Pegah,
BAHRAMI Mohammad
Publication year - 2013
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.12136
Subject(s) - foraminifera , marl , geology , paleontology , benthic zone , paleoecology , cretaceous , biostratigraphy , sedimentary depositional environment , structural basin , salinity , oceanography
To enable the lithostratigraphic and biostratigraphic study of the Gurpi Formation, within the ‘Dezak’ or Globigerina Marl, a stratigraphic section at Booraki, located to the NNW of Shiraz, SW Iran, through the late Cretaceous was examined. The formation consists of shale and greenish‐gray marls interbedded with cream limestone, brown sandstones and siltstones with an exposed thickness of 160 m in the studied section. Samples were taken at regular intervals in all yielding 14 genera and 16 different species of benthic and planktic foraminifera that allowed determination of the age of the beds as Maastrichtian. To examine the paleoecology of the formation, some important ecological factors including water level, salinity, and oxygen regime change during the depositional courses of the formation were analyzed. The density of foraminiferans decreases from the base to top of the Gurpi Formation whereas the ratio of planktic to benthic Foraminifera (i.e., P/B) and proportion of shallow‐water fauna increase. These foraminiferal changes indicate an increase and decrease in depth, temperature, salinity and oxygen, respectively, at the base and top of the Formation.