Mansehra Granite

Updated from the older Early Cambrian Rb-Sr whole-rock estimate (~516 Ma) to Early-Middle Ordovician crystallization ages (~478 Ma Mansehra, ~475 Ma leucogranites, ~466 Ma Hakale) from modern SHRIMP and LA-ICP-MS U-Pb zircon dating (Naeem et al. 2016). Era remains Paleozoic.

Naeem, M., Burg, J.-P., Ahmad, N., Chaudhry, M.N. & Khalid, P. (2016)

Kazmi & Jan (1997): the porphyritic two-mica Mansehra Granite (Hazara District) is an Early Palaeozoic, calc-alkaline S-type granite–granodiorite (quartz–albite/oligoclase–K-feldspar–biotite ± garnet, with feldspar megacrysts to 15 cm and a strong gneissose fabric; Susalgali Gneiss + Mansehra porphyritic granite + andalusite granite), intruding the Precambrian Tanawal Formation of the Hazara Nappe as thick folded sheets over >2,000 km². Rb-Sr isochron 516 Ma (Le Fort et al. 1980), variously termed 'Late Cambrian'/'Cambro-Ordovician' — slightly older than the curated ~478–466 Ma (Early–Middle Ordovician), recorded as a note.

Kazmi, A.H. & Jan, M.Q. (1997)

Kazmi & Abbasi (2008): the book calls the Mansehra Granite an Early Palaeozoic / Late Cambrian pluton with a 516 Ma Rb–Sr age (Le Fort et al. 1980), and treats a regional 466 ± 2 Ma date (Baig et al. 1989) as a later metamorphic event, not the intrusion age. The curated value (~478–466 Ma, Early–Middle Ordovician) is retained because it derives from a modern U–Pb zircon study (mansehra-upb-2016), which supersedes the 1980 Rb–Sr figure; the two are recorded together as the Rb-Sr-vs-U-Pb methodological difference.

Kazmi, A.H. & Abbasi, I.A. (2008)

Calkins et al. (1975): originally assigned the Mansehra Granite a Late Cretaceous to early Tertiary age (~80 Ma K-Ar, R.G. Davies) and interpreted it as synorogenic with the early Himalayan orogeny. This is SUPERSEDED by modern geochronology, which places the Mansehra Granite in the Cambrian–Ordovician (~470 Ma) Himalayan granite belt; the curated Ordovician age is retained and the Calkins assignment recorded only as a historical note.

Calkins, J.A., Offield, T.W., Abdullah, S.K.M. & Ali, S.T. (1975)

Ogasawara et al. (2018): zircon U-Pb dating gives 206Pb/238U crystallisation ages of 483–476 Ma (Early Ordovician), confirming and refining the curated Ordovician age (and definitively superseding the Late-Cretaceous ~80 Ma K-Ar age of Calkins et al. 1975). The Mansehra granite is a typical S-type Lesser Himalayan granite; inherited zircon cores at 889–664, 1862–1595 and 2029 Ma indicate a Late Neoproterozoic–Cambrian sedimentary protolith (max age ~664 Ma) derived from Paleoproterozoic crust (high initial 87Sr/86Sr 0.7324–0.7444; eNd(t) −9.2 to −8.6).

Ogasawara, M., Fukuyama, M., Siddiqui, R.H. & Zhao, Y. (2018)

LA-ICP-MS U-Pb zircon chronometry confirms an early-Palaeozoic (Cambro-Ordovician), Andean-type crystallization for the Mansehra Granitic Complex, consistent with the ~478-466 Ma assignment (Naeem et al. 2016).

Naeem, M., Burg, J.-P., Ahmad, N., Chaudhry, M.N. & Khalid, P. (2016)

DiPietro & Pogue (2004, after Treloar et al. 1989a): the ~500 Ma Mansehra augen orthogneiss is interlayered with Tanawal pelitic schist across the NW Indian-plate cover — corroborating the Cambro-Ordovician (~500 Ma) age of the Mansehra granite.

DiPietro, J.A. & Pogue, K.R. (2004)

Calkins et al. (1975, after Shams 1961): a light-coloured, medium- to coarse-grained, foliated (except around Mansehra) granite characterised by large twinned microcline phenocrysts (locally up to 5 in), with microcline–oligoclase–quartz and minor biotite/muscovite; a tourmaline-rich variety (the 'Hakale granite') and a foliated 'Susal Gali granite gneiss' are genetically related. Gravity and field data indicate a sheet-like body folded with its Tanawal Formation country rock; contact aureoles are weak (local cordierite schist).

Calkins, J.A., Offield, T.W., Abdullah, S.K.M. & Ali, S.T. (1975)

Shams & Ahmed (1968): the Paleozoic schists, gneisses and granite of the Mansehra-Amb area are cut by concordant tholeiitic dolerite sills (inches to >100 ft thick) along foliation planes, with unusually magnesian pyroxenes and highly magnesian olivine (Fo80–91) defining a tholeiitic iron-enrichment differentiation trend.

Shams, F.A. & Ahmed, Z. (1968)

In the Mansehra-Batgram area, quartz, quartz-ilmenite and quartz-kyanite veins cut the Mansehra Granite and associated gneisses/schists (Ashraf & Chaudhry 1974): simple quartz veins (98-99% quartz; a Chitta Batta dyke 34 ft wide and 1 mile long) occur within the granite, whereas ilmenite- and kyanite-bearing veins (kyanite blades 3-6 cm, locally after andalusite/chiastolite) are confined to the metamorphic host rocks.

Ashraf, M. & Chaudhry, M.N. (1974)

Ashraf & Chaudhry (1974) described six zoned granite pegmatites in the Dadar area (Basala village), emplaced in Barrovian kyanite-grade schists ~2 furlongs from the Mansehra Granite; the bodies (up to 6 x 3 m) grade from a cleavelandite-muscovite-garnet wall zone through beryl-bearing intermediate zones (with relict microcline perthite) to a milky quartz core (93-97% SiO2), extensively albitised during a late pneumatolytic stage — interpreted as granite pegmatites genetically linked to the Mansehra Granite.

Ashraf, M. & Chaudhry, M.N. (1974)