Palaeobathymetry of the Abderaz Formation using foraminifera, Iran

• Main Authors: Meysam Shafiee Ardestani, Ebrahim Ghasemi-Nejad
• Format: Manuscript
• Language: unknown
• Published: 2009
• Subjects: Ecology; Earth & Environment; Planktonic foraminifera
• Online Access: http://precedings.nature.com/documents/2787/version/1; http://hdl.handle.net/10101/npre.2009.2787.1

Abderaz Formation at its type section with an age of Turonian-early Campanian and a thickness of 300 m contains light grey shale and marl. The study of the planktonic foraminifera in isolated form led to differentiate three morphotype groups. The first group is characterized by trochospiral tests usually indicate shallow waters, the second group contains forms with strong ornamentations and the primary keels representing mid waters and finally compact trochospiral tests with keels known as deep water indices are included in the third group. Studies on the morphotypes showed a regressive cycle for Abderaz Formation. Also the planktonic to benthic ratio was calculated using Depth = e^(3.58718 + (0.03534 × %*p)^ equilibrium which explains that at the deposits 400 meter at total part of in this Formation. This study was intended to explore the marine sedimentation of Abderaz Formation in (outer neritic-upper bathyal) restrict and the provided curves from morphotypes changes are in full agreement with the curves of the sea level changes and planktonic foraminifer to epifauna benthic ratio.