Scleractinian Corals from the Early and Late Aptian of Baghin Area (Southwest of Kerman, Iran): Introduction and Paleoenvironmental Analysis

From the Early and Late Aptian sediments of the Baghin area, southwest of Kerman, Iran, a fairly low diverse scleractinian coral assemblage is described on the basis of paleoenvironmental factors for the first time. The fauna, collected from 6 stratigraphic horizons, encompasses 21 species from 15 genera, belonging to the families Actinastraeidae, Caryophylliidae, Columastraeidae, Eugyridae, Lasmogyridae, Latomeandridae, Rayasmiliidae, Solenocoeniidae and Stylinidae. The fauna is dominated by low corallite integration forms (plocoid and cerioid arrangements), while highly integrated corals (hydnophoroid, thamnasteroid, meandroid types) and solitary forms are subordinated. In the Baghin section, the δ¹³C values present a prominent negative excursion followed by a major positive excursion, which is considered geochemically characteristic of Oceanic Anoxic Event 1a (OAE1a). Additionally, the δ¹⁸O values suggest a pronounced warming of oceanic waters throughout the studied interval. Although the corals generally had favorable ecological conditions for development, no coral fabric was observed that would suggest biohermal development. The Aptian scleractinian assemblage of the Baghin area exhibits an example of a non-reef-building coral population, that thrived on marly substrate, along the southern rim of the eastern Tethys.