Holothurian sclerites from the Triassic of Jordan and their stratigraphic importance

Walid Sadeddin

doi:10.1144/jm.15.1.83

Abstract

Abstract. Holothurian selerites are some of the most stratigraphically important microfossils of the middle Triassic of Jordan. Stratigraphically and palaeogeographically important faunas have been obtained by dissolving Triassic carbonate rocks with a dilute acetic acid. The oldest forms, Acanthotheelia jordanica Sadeddin, Priscopedatus quadratus Kozur &amp; Mostler, and Tetravirga perforata Mostler, occur in the Hisban Formation (Anisian) in the area of the northeast corner of the Dead Sea and Wadi Abu Oneiz. North of this area in Wadi Salit, Ladinian holothurian faunas are especially characterized by the mass occurrence of Schizotheelia jordanica and Schizotheelia multiporata Kozur &amp; Sadeddin in the lower part of the section (Fassanian) and Theelia tubercula Kristan-Tollmann in the upper part (Longobardian). In spite of some differences, the Jordanian Middle Triassic holothurian faunas are similar to those from the Northern Alps and Germanic Basin, and the Himalayas. As yet, no holothurian selerites have been recovered from Jordanian Lower or Upper Triassic deposits.

Highlights

Holothurian sclerites are some o f the most stratigraphically important microfossils of the middle Triassic of Jordan
Holothurian :iclerites from Jordan were unknown until Kozur & Sadeddin (1990) described the first holothurian sclerites from Middle Jurassic carbonate rocks
Further investigations by dissolving Triassic carbonate rocks from different localities using dilute acetic acid solutions indicate that Triassic sediments in Jordan frequently contain holothurian sclerites

Summary

Introduction

Sample 8, collected from limestone beds with Trigonodus and Posidonia that are overlain by a 4 m volcanic intrusion (tracyandesite sill), contains the holothurian sclerite Theelia tiihrrc~ula Kristan-Tollmann and yields frequent conodonts (Pseiid~~,fzirni.shizr..ssosiorn.sis Gullo CYC Kozur). Which was collected from the marly limestone contains holothurian sclerites belonging to Theelia riihercirla Kristan-Tollmann, TlircTlirr cf T. harkeyi Kozur & Simon and frequent conodonts comprising exclusively Birrdirrovigntithirs nfiingoerz,si,s (Diebel) and B. nio.stleri Kozur.

Results

Conclusion