Abstract

The Tibetan plateau is associated with a pronounced satellite magnetic low. Forward modeling of this anomaly demonstrates that the crust underlying the Tibetan plateau is weakly magnetic compared to the crust on either side, and that the boundaries of the weakly magnetic region coincide closely with the topographic edges of the plateau (Himalaya, Kun Lun). Because there are no obvious changes in the bulk magnetization of the crust associated with the principal terrane boundaries within the plateau (Banggong and Yarlung-Zangbo sutures), the low likely manifests hot crust beneath Tibet. Forward modeling of the magnetic anomaly with simple assumptions suggests that the Curie isotherm is likely to reside in the upper crust across the Tibetan plateau (∼15 km depth), implying that granite minimum melt temperature (∼600–650 °C) is also achieved in the upper crust across the plateau (∼16–18 km depth). This inference is consistent with the shallow depth extent of earthquakes in Tibet, and with the recent suggestion that melt may be areally widespread within the Tibetan crust.

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