Bir Zidan Member, Al Jir Formation (Eocene of Libya)

Where: Libya (30.9° N, 15.5° E: paleocoordinates 24.4° N, 11.7° E)

• coordinate stated in text

• local area-level geographic resolution

When: Bir Zidan Member (Al Jir Formation), Lutetian (47.8 - 41.3 Ma)

• LITHOSTRATIGRAPHIC RELATIONSHIPS: From the Bir Zidan Mbr of the Al Jir Fm (formerly Gir Fm of Bar and Weegar, 1972), which disconformably overlies the Bishimah Fm (Late Paleocene-Middle Eocene), and is overlain with the Wadi Thamet Fm (Middle-Late Eocene). AGE: Lutetian, on the basis of microfossil (foraminiferal) and molluscan biostratigraphy. THICKNESS: Approximately less than 20 m.

• member-level stratigraphic resolution

Environment/lithology: poorly lithified, dolomitic, shelly/skeletal, white, yellow limestone

• ENVIRONMENT: Shallow marine neritic to lagoonal environment, with local brackish influence.
• GENERAL LITHOLOGY: Several lithologies including light cream colored chalky limestone, unfossiliferous white chalky limestone, cream to dull white chalky limestone with regular patches of marly and dolomitized limestone rich in molluscan fossils, slightly dolomitized fossiliferous chalky limestone, and chalky limestone with rare fossils. LITHIFICATION: Poorly-lithified, not stated, but apparent from facies description.

Size classes: macrofossils, microfossils

Collection methods: surface (in situ),

• COLLECTORS: Not stated, possibly multiple collectors. REPOSITORY: Unknown.

Primary reference: M. F. Megerisi and V. D. Mamgain. 1980. The Upper Cretaceous-Tertiary Formations of northern Libya: a synthesis. Department of Geological Researches and Mining Bulletin 12:1-85 [A. Hendy/A. Hendy]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 42125: authorized by Austin Hendy, entered by Austin Hendy on 24.07.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Limited, but including bivalvia, gastropoda, echinoids, algae, and foraminifera. NOMENCLATURE: Somewhat antiquated nomenclature, but identified to species and subgenus resolution.
unclassified
  -
Foraminifera
 Globigerinina - Truncorotaloididae
Globothalamea
 Rotaliida - Discorbidae
Discorbis sp. Lamarck 1804
Foraminifera
 Lituolida - Ammobaculinidae
 Globigerinoidea - Globorotaliidae
Globorotalia sp. Cushman 1927
 Globigerinoidea - Globigerinidae
Globigerina sp. d'Orbigny 1826
 Textulariacea - Valvulinidae
Lituonella sp. Schlumberger and Douvillé 1905
Tubothalamea
 Miliolida - Soritidae
 Miliolida - Peneroplidae
Spirolina sp. Lamarck 1804
 Miliolida - Alveolinidae
Alveolinidae indet. Ehrenberg 1839
Fasciolites sp. Parkinson 1811
 Miliolida - Rhapydioninidae
 Miliolida - Hauerinidae
Quinqueloculina sp. d'Orbigny 1826
 Miliolida - Miliolidae
Spiroloculina sp. d'Orbigny 1826
Foraminifera
 Rotaliacea - Rotaliidae
 Nummulitacea - Nummulitidae
 Charales - Characea
Chara sp. Linnaeus 1753 stonewort
Algae
 Charales - Characeae
Raskyella
  -
Raskyella pecki
Algae; SUBSPECIES: Raskyella pecki meridonale
Psilochara
  -
Psilochara sp. Grambast 1959
Algae
Chlorophyceae
 Dasycladales - Dasycladaceae
Neomeris sp. Lamouroux 1816
Algae
 Dasycladales -
Acicularia sp. d'Archiac 1843
Algae
Ulvophyceae
 Bryopsidales - Halimedaceae
Halimeda sp. Lamouroux 1812
Algae
Gastropoda
 Cerithioidea - Turritellidae
 Sorbeoconcha - Cypraeidae
"Gisortia (Vicetia) gigantea" = Gisortia gigantea
"Gisortia (Vicetia) gigantea" = Gisortia gigantea Munster 1828 cowry
 Sorbeoconcha - Naticidae
Bivalvia
 Pectinida - Anomiidae
 Ostreida - Malleidae
 Ostreida - Gryphaeidae
 Ostreida - Ostreidae
"Ostrea multicostata" = Cubitostrea multicostata Deshayes 1832 oyster
SUBSPECIES: O. multicostata strictiplicata
Ostrea cymbula Lamarck 1806 oyster
SUBSPECIES: O. cymbula ramosa
 Carditida - Carditidae
Echinoidea
 Clypeasteroida - Fibulariidae
 Clypeasteroida - Laganidae
Sismondia ocitana sand dollar