ammonites
Longing Gap Radiolarians, K 47 (Jurassic of Antarctica)

Where: Antarctica (64.5° S, 59.0° W: paleocoordinates 54.9° S, 35.5° W)

• coordinate based on unpublished field data

• hand sample-level geographic resolution

When: Ameghino Member (Ameghino Formation), Late/Upper Tithonian (150.8 - 145.5 Ma)

• bed-level stratigraphic resolution

Environment/lithology: basinal (); lithified, concretionary, tuffaceous, black mudstone

• Anoxic conditions prevailed especially in the Longing Member; this is indicated by the often lacking bioturbation and rare horizons with benthonic fossils. In the Ameghino Member moderately intense bioturbation (Zoophycos, Chondrites, Planolites) and a consequent destruction of lamination indicate dysaerobic conditions. Doyle and Whitham (1991) attribute this environmental change to an uplift of the depositional environment above a permanent pyknocline. The submarine relief was very low and a simple hemipelagic sedimentation was dominant.
• Mudstone concretion with tuff layers

Size class: microfossils

Preservation: concretion

Collection methods: bulk, chemical, hydrochloric, sieve,

• Radiolarians only. Additional faunal elements are sponge spicules and very rare foraminifera.

Primary reference: W. Kiessling. 1999. Late Jurassic radiolarians from the Antarctic Peninsula. Micropaleontology 45(S1):1-96 [W. Kiessling/W. Kiessling] more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 46969: authorized by Wolfgang Kiessling, entered by Wolfgang Kiessling on 27.01.2005