oa Magnetic Susceptibility Observation Across Himalaya-Karakoram Range, Northern Pakistan

Low field magnetic susceptibility was observed for the rocks exposed along Karakoram Highway, northern Pakistan, traversing from Hasan Abdal town, north western margin of Indo-Pakistan subcontinent to Ghunjerab river, southern part of the Karakoram block which is a part of Eurasian continent. The Kohistan block between these two terranes has relatively higher values of magnetic susceptibility values Koenigsberger ratio shows that gabbro-norite layering in the Kohistan block might has significant effect of natural remanent magnetization on geomagnetic anomalies. Most of granitic rocks of the block are correlated with ilmenite series showing low magnetic susceptibility while granotoids in northern part of the Kohistan block and Indo-Pakistan subcontinent belong to magnetite series. In the Kohistan block, pre-collisional granites are of magnetite series, while in the case of Indo-Pakistan subcontinent the granitic rocks yielding old age (e.g. 550 Ma) are of magnetite series and granitic rocks with younger radiometric age correspond to ilmenite series.