Precambrian • Proterozoic GSP memoir

Petaro-Hyderabad Ridge

Precambrian

Cited in 2 sources Last reviewed Jul 14, 2026

Unit summary

Rank: Not recorded
Status: Published
Age: Precambrian · ProterozoicPrecambrian
Named by: Not recorded
Type locality: Petaro-Hyderabad area, Sindh (subsurface)25.5200°N, 68.3100°E
Thickness: Unknown (buried feature)
Lithology: Crystalline basement (granite, gneiss — subsurface)
Synonyms: Not recorded

A buried Precambrian basement high in Lower Sindh (Petaro-Hyderabad area), identified from gravity and aeromagnetic surveys, separating the Thar Platform from the main Indus Basin.

Buried basement high in Lower Sindh known from gravity and aeromagnetic surveys. Separates the Thar Platform from the main Indus Basin. Important structural control on Mesozoic-Cenozoic sedimentation in Lower Indus.

Fossils

Not recorded

Contacts

In the Sindh Province column

IgneousConformable

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

Sindh Province Indo-Pakistan Shield

Basin: Not recorded
Region: Not recorded
Depositional environment: Not recorded
Coordinates: 25.5200°N, 68.3100°E

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Correlation

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

Economic significance

Reservoir

Controls gas field locations in Lower Sindh

Remarks

An important structural control on Mesozoic-Cenozoic sedimentation in the Lower Indus Basin; known only from geophysics and rare drill data, its crystalline-basement age is unconstrained beyond a general Precambrian assignment.

Sources (2)

Malkani, M.S. & Mahmood, Z. (2017). Stratigraphy of Pakistan. Geological Survey of Pakistan, Memoir Vol. 24.
OpenStreetMap contributors and GEOnet Names Server (public geographic gazetteers), used to geolocate named GSP type localities to approximate decimal coordinates.

Reviewer confidence: low

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: Appears in a single-author Geological Survey of Pakistan memoir (Malkani & Mahmood 2017), not cross-confirmed against the Shah lexicon. The Stratigraphic Committee of Pakistan is largely inactive, so documented provenance — not formal ratification — is the available signal.

Cite this unit

APA

Qudsi, L. (2026). Petaro-Hyderabad Ridge. In Pakistan Stratigraphy Dataset [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21363991

BibTeX

@misc{stratigraphypk_petaroridgebasement,
  author    = {Qudsi, Lareb},
  title     = {{Petaro-Hyderabad Ridge} --- 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/petaro-ridge-basement (accessed August 30, 2026).