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Description of  Geology of the Sacred Valley of the Incas

The citadel of Machu Picchu sits within a batholith of granitic rock of which material the Incas built the structures. Many of the valleys are formed by glacial action forming large gravel moraines at their terminations. Hiram Bingham re-located the ancient citadel which was known by the local indigenous people, descended from the Incas. Sinkholes at Moray are formed by the dissolution of the underlying Maras formation consisting of salt and gypsum. This process forms the 4 sinkholes of the archeological site of Moray. The dissolved salt flows downstream to form the Salinas where local salt farmers collect the salt. The Vilcanota River is the only major community occupying an Inca temple site. The temple site is built of material from the Ollantaytambo formation of early Ordovician age of quartzites, sandstone, shales and ignimbrites. From across the Vilconota River, large pinkish granite porphyry blocks were dragged to the top to adorn the temple. Pisac is also near the Vilcanota River and made of Permo-Triassic breccias and conglomerates consisting of limestones, volcanic and quartzites clasts. The temple site area is made of Rumicolca andesite ashlars. The flow-banded rhyolite intrusive forms a defensive tunnel within this unit leading to the ceremonial area where the Spaniards had destroyed the Intiwatana. The Inca leader Pachactec was responsible for the construction of the beautiful city of Cusco, Machu Picchu and Sacsayhuaman, the head of the puma. A Cenozoic age diorite intrusive with calcite veinlets, epidote and weak alteration is within this ceremonial place. Glacial grooves are cut into the Rodadero intrusive. Large limestone blocks of many tons of the Upper Cretaceous were quarried from the Sisicancha quarry three kilometers due east of the fortress. This is the place of the winter solecists celebration of Inti Raymi. Qoricancha, the place of the sun, moon and star temples is built of imperial Rumicolca andesite. A large 3-meter golden disc representing the sun and a silver disc representing the moon decorated the temples. Read more