Microfacial Study, Fossil Assemblages and Depositional Environment of Wadi As Sir Limestone Formation, Jordan
This paper studies the microfacies, fossil contents, and the depositional environment
of Wadi As Sir Limestone Formation exposed in the Al-tayyar area
Zarqa Governorate, Northeastern Jordan. A total number of 35 samples were
collected from a 30 m thick quarry section and used to prepare 35 thin sections.
Some samples were washed over a 63 ?m sieve, oven-dried at 50?C,
sieved, and picked for benthic foraminifera analysis. Microscope analysis
used to describe the microfacies and fossil contents. Four microfacies types
and four lithological units are distinguished and described from the bottom
to the top; the chalky unit (Unit-1) composed of bioclastic wackestone and
biomicrite microfacies, and the dolomitic unit (Unit-2) immediately is existed
above unit 1 composed dominantly of bioclastic mudstone and biomicrite
microfacies. Marly limestone (Unit-3) is the following upwardly unit composed
of bioclastic packestone and biosparite Microfacies, and the uppermost
unit is limestone (Unit-4) consisted of bioclastic grainstone and biosparite
microfacies. The fossil contents that were recognized in the studied thin sections
and samples; bivalves, gastropods, pelecypods, cephalopods echinoderms,
radiolarian, stromatoporoids, bone fragments, Saccaminopsis sp., Cibicidoides
sp., Cibicides sp., Cyclammina sp., calcareous algae (Koninckopora
and gymnocodiaceans ), worm tubes, serpulids, and plentiful ostracods. The
current study indicates that the Wadi As Sir Limestone Formation has deposited
in a restricted circulation shallow shelf with low energy conditions most
probably lagoonal environment.