Masol (India, Punjab): Horses (Equus) and hominins in the sub-Himalayan floodplain as early as 2.95 Ma. A pluridisciplinary synthesis and a hypothesis of dispersal routes from North America (Equus) and North Africa (hominins)

Late Pliocene fossil deposits outcrop in the Siwalik Frontal Range along the North Western Himalayas. These formations are located in the Subathu sub-basin dispersed over 70 km in different fossiliferous sectors between the 30th and 31st parallels north: the Chandigarh anticlinorium, the Ghaggar-Moginand and Khetpurali sectors and then the Saketi-Kanthro and Haripur sections. Undisputable marks of butchery and lithic industries have been regularly collected between 2008 and 2019 in the fossiliferous Quranwala Zone (QZ) of the Masol Formation located in the Chandigarh anticlinorium. The production of lithic tools was definitively confirmed in 2017 by at least one chopper in situ. This biozone, 50 meters thick, perfectly circumscribed and geomorphologically isolated, yielded the First Appearance Datum (FAD) of Equus in Eurasia and its oldest co-existence with Hipparion. Our magnetostratigraphy dated the Quranwala Zone and hominin activities thanks to a short excursion measured at its lower limit and whose minimum age can be the one at 2.68 Ma and the oldest at 2.95 Ma (Huahine). We present a synthesis of the different fossiliferous localities with their sedimentation rates on a regional scale and which have constrained the age of the excursion to 2.95 Ma. This date allows us to reconstruct the environmental and climatic factors responsible for the appearance and disappearance of the Quranwala Zone by placing them on both regional and global scales. The FAD of Equus is explained by its dispersal from North America to Asia thanks to the formation of Beringia during the cold and dry interval MIS G 20 (3.043–3.025 Ma). The FAD of hominin activities since 2.95 Ma can be explained by a northward shift of the Summer Inter-Tropical Convergence Zone (ITCZ) during the final peak of a warming at the end of the Piacenzian at 2.97–2.96 Ma and allowing a dispersal in western Asia. We propose the most parsimonious and consistent paleoclimatic hypothesis of hominin dispersal from latitudes 30°–31° that covered the river systems along the ITCZ from Northern Africa to the Sub-Himalayan plain and which accounts the formation of the Quranwala Zone including Equus before the onset of glaciation at 2.75 Ma with a common passage through the Afghan depression of Seistan.