Nari Formation
Oligocene
Paleogene in the time scale →Cited in 10 sources Last reviewed Aug 4, 2026
- Rank
- Not recorded
- Status
- Published
- Age
- Cenozoic · Paleogene · OligoceneOligocene
- Named by
- Blanford (1876)
- Type locality
- Gaj River gorge, Kirthar Range26.8750°N, 67.3200°E
- Thickness
- 300-500 m
- Lithology
- Brown, fine- to coarse-grained sandstone in the upper part with shale and subordinate limestone below.
- Synonyms
- Not recorded
A widespread Oligocene sandstone-and-shale above the Kirthar limestone — coal-bearing and a reservoir.
Named after Nari River. Clastic sequence marking transition from open marine to restricted conditions. Records Tethys closure in lower Indus.
Fossils
Contacts
Band colour = period; texture = dominant rock type. Lines between bands mark the contact type; dotted = no contact recorded in the sources (not a claim of conformity). True scale makes height ∝ recorded thickness; hatched = thickness not recorded. Ages approximate, for ordering.
This unit (highlighted) within its province column; faded ends continue above and below. Line style marks the contact type.
Distribution & setting
- Basin
- Not recorded
- Region
- Not recorded
- Depositional environment
- marginal marine, deltaic
- Coordinates
- 26.8750°N, 67.3200°E
Correlation
Not recorded. Compare this unit against other basins on the correlation panel →
Economic significance
Contains workable coal seams (Nari coal) and forms reservoir intervals.
Remarks
A widespread Oligocene sandstone-shale unit conformably overlying the Kirthar Formation; marks the onset of clastic, marginal-marine deposition before the Miocene Gaj Formation.
Research notes (6)
Field-by-field findings drawn from the cited literature. Every statement is traced to a registered source — follow a citation for the full reference.
Age & correlation (2)
-
Brohi et al. (2009): the Oligocene Nari Formation is part of the measured Khorwari/Surjan Anticline Tertiary succession (Laki → Tiyon → Nari → Gaj → Manchar → Dada), studied for economic potential. Corroborates the Oligocene age.
Brohi, I.A., Bablani, S.A. & Solangi, S.H. (2009)
-
Larger-foraminiferal biozonation near Karachi (Khan, 1968): the Upper Nari Formation ranges Rupelian to Early Aquitanian; its upper part carries fossiliferous marine limestone bands of the Spiroclypeus blanckenhorni ornata Zone (Aquitanian) — Spiroclypeus blanckenhorni ornata, S. ranjae, S. margaritatus, Eulepidina dilatata/formosa, Nephrolepidina cf. angulosa and early Miogypsinoides — whereas the arenaceous fluvio-deltaic facies of northern Sind is Chattian.
Khan, M.H. (1968)
Thickness (1)
-
Type-section thickness (Shah, 2009): Gaj Group: ~660 m type locality; 1700 m Gaj River; 1200–2400 m Mazarani-Miangun; 90–450 m Sulaiman. Type locality: Gaj River area (Gaj Group type locality ~660 m). Recorded from the GSP lexicon (Memoir 22); the existing thickness field is retained.
Shah, S.M.I. (2009)
Depositional environment (1)
-
Ahmedani et al. (2025), Hundi Anticline (Karachi Embayment): outcrop facies analysis of the mixed carbonate-clastic Nari Formation recognises six facies (arenaceous limestone, calcareous sandstone, argillaceous sandstone, laterite/oxidised sandstone, arenaceous shale, calcareous mudstone) and indicates deposition across a range of environments from outer ramp to fluvio-deltaic, in an overall progradational succession interpreted as a response to regional regression during the Himalayan orogeny.
Economic significance (1)
-
Ahmedani et al. (2024), diagenesis of the Nari Formation sandstone at the Nari (Nari Nai) River section, Southern Kirthar Range (petrography, XRD, SEM, EDX): three diagenetic stages are recognised - eogenesis (syn-depositional cementation with minor compaction), mesogenesis (Pliocene compaction, dissolution, alteration and quartz overgrowth) and telogenesis (Pliocene-Pleistocene uplift, grain fracturing and oxidation). Iron oxide is the dominant cement (then calcite and dolomite) and cementation has largely destroyed primary porosity (residual 1-18%), so reservoir quality is diagenetically degraded and controlled by the Oligocene-Pleistocene tectonic evolution of the NW Indian-plate margin.
Ahmedani, S.B., Agheem, M.H., Hakro, A.A.A.D., Halepoto, A.A., Lashari, R.A. & Thebo, G.M. (2024)
Geological significance (1)
-
Ahmedani et al. (2025): petrography distinguishes five limestone-dominated microfacies and two sandstone petrofacies (sub-arkose and quartz arenite), the quartz-rich clastics indicating a granitic source most likely derived from the Indian Craton to the east — tying the Oligocene Nari clastic supply of the Karachi Embayment to eastern cratonic provenance.
Sources (9)
- Malkani, M.S. & Mahmood, Z. (2017). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 24.
- Kazmi, A.H. & Jan, M.Q. (1997). Geology and Tectonics of Pakistan. Graphic Publishers, Karachi.
- OpenStreetMap contributors and GEOnet Names Server (public geographic gazetteers), used to geolocate named GSP type localities to approximate decimal coordinates.
- Indian Plate Lexicon (indplex.geolex.org), Geological Society of India and international compilation.
- Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 22.
- Ahmedani, S.B., Hakro, A.A.A.D., Mastoi, A.S., Halepoto, A.A., Sahito, A.G., Akhtar, S. & Lashari, R.A. (2025). Clastic Source and Depositional Environment of Mixed Carbonate-Clastic Sequences in the Oligocene Nari Formation from the Hundi Anticline, Karachi Embayment, Indus Basin, Pakistan. Earth Sciences Research Journal, 29(2), 149-167.
- Kazmi, A.H. & Abbasi, I.A. (2008). Stratigraphy and Historical Geology of Pakistan. Department & National Centre of Excellence in Geology, University of Peshawar, Peshawar. 524 pp. ISBN 978-969-9119.
- Brohi, I.A., Bablani, S.A. & Solangi, S.H. (2009). Geology and Economic Significance of Tertiary Rocks, Khorwari Section, Surjan Anticline, Thano Bula Khan, Sindh. Sindh University Research Journal (Science Series), 41(1), 95-106.
- Ahmedani, S.B., Agheem, M.H., Hakro, A.A.A.D., Halepoto, A.A., Lashari, R.A. & Thebo, G.M. (2024). Integrated Petrographical, Mineralogical, and Geochemical Investigation to Evaluate Diagenesis of Sandstone: A Case Study of the Oligocene Nari Formation from Southern Kirthar Range, Pakistan. Journal of Himalayan Earth Sciences, 57(1), 1-22.
Reviewer confidence: high
Every fact on this page is source-cited. This entry is part of the peer-archived Pakistan Stratigraphy Dataset (doi.org/10.5281/zenodo.21363991, CC‑BY‑4.0).
Lexicon status: Name attested in the Shah (1977/2009) Geological Survey of Pakistan compilation — the national stratigraphic lexicon. This records where the name is documented; it is not an endorsement of the unit’s definition, age or figures.
Cite this unit
Qudsi, L. (2026). Nari Formation. In Pakistan Stratigraphy Dataset [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21363991
@misc{stratigraphypk_nariformation,
author = {Qudsi, Lareb},
title = {{Nari Formation} --- Pakistan Stratigraphy Dataset},
year = {2026},
publisher = {Zenodo},
doi = {10.5281/zenodo.21363991},
url = {https://doi.org/10.5281/zenodo.21363991}
} Archived dataset: doi.org/10.5281/zenodo.21363991 (CC‑BY‑4.0) · Direct link to this entry: https://stratigraphy.pk/formation/nari-formation (accessed October 29, 2026).
To cite the unit's original definition instead, see: Blanford (1876).
Related units
More from Kirthar Range
Same age (Cenozoic · Paleogene)
Saved on this device only.