ammonites
Ridge north of Wadi Alwa, Wadi Alwa I, collection 118B (Triassic of Oman)

Where: Oman (23.1° N, 58.4° E: paleocoordinates 28.3° S, 54.5° E)

• coordinate estimated from map

• small collection-level geographic resolution

When: Spathian (251.3 - 247.2 Ma)

• Wadi Alwa I. The maximum dimension is at least 100 m. It is tabular preserving about 25 m of strata, mostly red limestone. The strata dip easterly at a low

•angle. Beds form a small bluff where a sequence of three ammonoid beds (ll8A,B,C) was determined in a stratigraphic thickness of about 25 m. Collection 118B.

• bed-level stratigraphic resolution

Environment/lithology: basinal (); lithified, argillaceous limestone

• 'From a lithofacies standpoint these rocks are more comparable with the 'Ammonitico Rosso'. The Ammonitico Rosso facies, like the Hallstatt, is restricted to the Tethys but the typical occurrences are Jurassic, not Triassic.

•The environment indicated by this facies was probably not exactly like that of the Halltstatt limestones, but was perhaps influenced by the presence of fine-grained terrigenous sediment.'

• 'red rocks, but different from the Hallstatt-type limestones, being nodular and of a marly nature.'

Size class: macrofossils

Collection methods: Localities at Wadi Alwa were found in the winter of 1980-1981 by members of an expedition organized by Imperial College, London. The party included G. Loftus and G. Nichols. In 1984 the writers spent three days studying three localities at Wadi Alwa.

Primary reference: E. T. Tozer and T. J. Calon. 1990. Triassic ammonoids from Jabal Safra and Wadi Alwa, Oman, and their significance. In: Robertson, A. H. F., Searle, M. P. & Ries, A. C. (eds) The Geology and Tectonics of the oman Region Geological Society, London, Special Publication (49)203-211 [M. Aberhan/S. Nurnberg] more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 73253: authorized by Martin Aberhan, entered by Sabine Nürnberg on 07.06.2007