Fars Gr

Cenozoic

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Early Paleozoic

Fars Gr

Period:

Neogene

Age Interval:

Late Oligocene – earliest Pleistocene, On (1,2)

Province:
Oman

Type Locality and Naming

Type Section: Fars Province, southern Iran. "The ‘Fars’ is an Iranian rock-unit term widely and loosely applied around the Gulf area outside Iran to embrace younger Tertiary sediments that were, in many areas, not further subdivided." In Oman subsurface, it is considered a Group status (unlike the Fars Fm elsewhere) with 2 formations: a lower Taqa Fm with carbonates, and an upper Dhalaima Fm of dolomites to shales. Oman outcrop has Barzaman Fm and Sawadi Fm. Column: Oman Subsurface, Oman Outcrop

Synonym:

Lithology and Thickness

In northern Oman, the Fars Group is represented by the Dhulaima Fm (formerly Clastics and Evaporites Fm), consisting largely of dolomites, limestones, evaporites and shales. The dolomites are often rich in gastropods and bivalves. In South and Central Oman, the Group is represented by the Taqa Fm (generally much thinner), consisting largely of limestones and dolomites. These interfinger in central Oman.

In outcrop, the generalized succession is sandstone-evaporites above limestone; see Barzaman Fm and Sawadi Fm. Sequence Stratigraphy: Part of Megasequence AP11 (Sharland et al., 2001). Sharland et al. (2004, see also 2001) place their renumbered Early Miocene MFS Ng10, and their Oligocene MFS Pg50 (previously Ng10), MFS Pg40 and MFS Pg30 surfaces within the Taqa Formation of southern Oman."

Lithology Pattern:

Clayey limestone

Relationships and Distribution

Lower contact

"The base is effectively defined by a region-wide event involving a hiatus or marked change of sedimentary regime during the Late Eocene – Oligocene." The Fars Gr in Oman unconformably overlies the Hadhramaut Gr (Dammam Fm)

Upper contact

This is the youngest unit

Regional extent

"The Group occurs throughout Interior Oman up to outcrop areas to the north, east and south. It is limited to the west, at approximately E55°15’ by a north- south outcrop of the Hadhramaut Group."

GeoJSON

null

Fossils

"Biostratigraphy: Biozones F78 (Peneroplis farsensis, Miocene) and F77 (Miogypsina sp., Nummulites intermedius, Oligocene) (formerly referred to as FZV and FZU, respectively)."

Age

Chattian – Gelasian. "ca. 33–1.8 Ma . . . Although Hughes Clarke (1988) stated an Oligocene to Pliocene age for the Fars Group in general, the oldest and youngest limits of the Group are poorly defined in Oman. Often only Miocene fauna are recorded with any degree of confidence (Figure 3.2). The presence of Nummulites intermedius is used to confirm an Early Oligocene age (in northern Oman), but care must be taken as reworked Oligocene and Eocene taxa can be recorded in Miocene Fars sediments."

Age Span:

Beginning stage:

Chattian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

25.16

Ending stage:

Gelasian

Fraction up in the ending stage:

1.0

Ending date (Ma):

1.80

Depositional setting

Depositional pattern:

Additional Information

Compiler:

Forbes, G.A., Hansen, H.S.M., and Shreurs, J., 2010. Lexicon of Oman: Subsurface Stratigraphy. Gulf Petrolink, 371 pp. (plus enclosures and CD); and Forbes, G.A., Hansen, H.S.M., and Shreurs, J., 2010. Lexicon of Oman: Subsurface Stratigraphy. Gulf Petrolink, 371 pp. (plus enclosures and CD); and Middle East Geological Timescale 2008 Al-Husseini, Journal of Middle East Petroleum Geosciences v 13. no. 4