PALEONTOLOGICAL NOTES ABOUT TERTIARY ECHINODERMS FROM NORTHEAST LIBYA

Echinoderabstractms are good indicators of paleoenvironment and paleotemperature around the world. These marine organisms are well represented in the geologic record from the Cambrian to the Holocene, with five extant classes in the modern oceans. In Tertiary rocks of northeastern Libya, fossil echinoderms are widely distributed, with high genus and species diversity. One hundred-fifty echinoderm–bearing samples were collected from several sections in Northeast Libya to aid in paleoenviromental reconstruction.

One hundred and fifty fossil echinoderms from the Oligocene and Miocene rocks of the northeastern Libya vary from section to section in diversity and abundance, but all appear to be associated with lagoonal or backreef conditions. An exception to this may be the fossil echinoderms collected from the Faydiah Formation. These fossils appear to be in a deep-water setting, but may have been transported down slope from a relict deposit representing a shallow water environment. Allowing for the possibility of transport, in situ echinoderm fossils may be a good indicator of lagoonal environmental conditions in the Oligocene and Miocene of northeastern Libya.

In the Al Fatayah Quarry, the lower portion of the Oligo-Miocene AlFaydiah Formation contains abundant Echinoderms of only one species. In the Daryanah Al Abyar road cut, the lower Oligocene Al Abraq Formation contains an abundant, well-preserved echinoderm fauna consisting of three species associated with green and red algae found in the lower part of the section. In the sluq Al Abyar road cut, the lower part of the Miocene Benghazi Formation (Ar Rajmah Group) contains a high diversity of macro- and micro-invertebrates, including calcareous green and red algae, foraminifera, and echinoderms. In the Ashabi area, Formation (M) outcrops in rocks of middle Miocene to middle Pliocene age. This section has an abundant vertebrate (mammalian) fauna, and newly-described the micro-and macro-invertebrate fauna in it. Interestingly enough, most of the echinoderms are associated with Miocene aged reefs in the lower part of this section. The abundance of calcareous algae indicates a lagoonal paleoenvironment for the echinoderm-bearing samples.