Mesozoic • Cretaceous In GSP lexicon

Sinjrani Volcanic Group

Middle to Late Cretaceous (Aptian-Santonian)

Cited in 5 sources Last reviewed Jul 18, 2026

Unit summary

Rank: Not recorded
Status: Published
Age: Mesozoic · Cretaceous · Late CretaceousMiddle to Late Cretaceous (Aptian-Santonian)
Named by: HSC (1961)
Type locality: Chagai (after the Sinjrani tribe)
Thickness: 900-1200 m
Lithology: Agglomerate, volcanic conglomerate, tuff and basaltic-andesitic lava with subordinate shale, sandstone and limestone.
Synonyms: Not recorded

The oldest volcanic pile of the Chagai arc — Cretaceous lavas and tuffs that also host part of the region's copper mineralisation.

Named after Sinjrani tribe of Chagai. Volcaniclastic sequence with minor sedimentary interbeds. Invaded by Chagai intrusions.

Fossils

Algae Foraminifera Corals (in limestone interbeds)

Contacts

In the Chagai Hills column

LimestoneShale / mudIgneousFossils recordedConformable

Band colour = period; texture = dominant rock type. Lines between bands mark the contact type. 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

Chagai Hills

Basin: Not recorded
Region: Not recorded
Depositional environment: volcanic-arc, submarine
Coordinates: Not recorded

Correlation

Not recorded. Compare this unit against other basins on the correlation panel →

Economic significance

Metals & minerals

One of the sedimentary/volcanic wall-rock units that host the Chagai porphyry copper deposits (Saindak, Reko Diq).

Remarks

The basal Cretaceous volcanic pile of the Chagai–Raskoh magmatic arc, recording the early (tholeiitic) stage of subduction-related volcanism; intruded by the Chagai batholiths.

Sources (4)

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.
Perelló, J., Razique, A., Schloderer, J. et al. (2008). The Chagai Porphyry Copper Belt, Baluchistan Province, Pakistan. Economic Geology, 103(8), 1583-1612.
Shah, S.M.I. (2009). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 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

APA

Qudsi, L. (2026). Sinjrani Volcanic Group. In Pakistan Stratigraphy Dataset [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21363991

BibTeX

@misc{stratigraphypk_sinjranivolcanicgroup,
  author    = {Qudsi, Lareb},
  title     = {{Sinjrani Volcanic Group} --- 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/sinjrani-volcanic-group (accessed September 5, 2026).

To cite the unit's original definition instead, see: HSC (1961).

Above · younger

Humai Formation

Cretaceous