Alan Fm
Period:
Jurassic
Age Interval:
Toarcian, Iq2
Province:
Iraq, Iran
Type Locality and Naming
Column: Central Iraq, Column: Zagros belt (general), Column: Iran East; Uppermost formation in Khane Khat Fm in Iran
Synonym:
Lithology and Thickness
Consists of bedded anhydrites with subordinate pseudo-oolitic limestones. Lateral changes, i.e. the frequent wedging out by the anhydrites are typical for the formation and greatly affect its thickness. 87m thick at type section.
Lithology Pattern:
Evaporite
Relationships and Distribution
Lower contact
Regionally, the schematic strat column indicates the next older unit as Mus Fm
Upper contact
Regionally, the schematic strat column indicates the next younger unit as Muhaiwir Fm. In Iran, it is Sargelu Fm
Regional extent
The equivalent formation on the surface in Rutba Uplift (W Iraq) may be the upper part of the Amij formation.
GeoJSON
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Fossils
Age
Toarcian
Age Span:
Beginning stage:
Toarcian
Fraction up in beginning stage:
0.7
Beginning date (Ma):
177.55
Ending stage:
Toarcian
Fraction up in the ending stage:
0.8
Ending date (Ma):
176.60
Depositional setting
Depositional pattern:
Additional Information
Compiler:
From S. Z. Jassim and J. C. Goff, Geology of Iraq, 2006. pg 105, Fig. 9-1: "Stratigraphic correlation of the Late Permian-Liassic Megasequence (AP6)."