Unlike other cart ruts found elsewhere in the world, the Azorean cart-ruts, engraved on volcanic stone, at the middle of the Atlantic, raise many questions: How old are they? Who created them? Were they made during a short or long time? These mysteriously enigmatic parallel grooves are noticed on the hard volcanic rock of the nine Azorean Islands in several locations. Recent scientific evidences have provided some support to the hypothesis of human presence in the Azores Islands before Portuguese settlement during the 15th century. Are the Azorean cart-ruts pre-Portuguese? Here we try to establish a chronology for the cart-ruts of Terceira Island, Azores, Portugal, using a historical approach, a geological approach and also a 14C dating approach, the last one obtained by dating a placic horizon found in the grooves of the cart-ruts named “Passage of the Beasts”, which indicates the presence of human activity in the island at least during the 11th century, or probably before. The date obtained is consistent with another date achieved through similar methods for a man-made basin in the same island and is also consistent with the historiographical records.

Source: Dating the Cart-Ruts of Terceira Island, Azores, Portugal

https://www.scirp.org/Journal/PaperInformation.aspx?PaperID=86557&fbclid=IwAR2gI_cr_uIsfE5EL7rMdyBPv6-UpMjk_3q8QYzByErhxlINmFbm478M-_U