The masks seems to defy pure origins, bearing the hallmark of synthetic craftsmanship and deliberate placement upon the rock.
Is the masks a part of an historical statue, or does it stand alone? What significance would possibly its placement maintain, might it signify a sacred relic from an historical civilization that when inhabited the planet or would possibly the masks function a homage to an historical deity?
But, who created this masks?
Hyperlinks:
SOL 4168: https://mars.nasa.gov/raw_images/1326548/
SOL 4168: https://mars.nasa.gov/raw_images/1326546/
Gigapan Neville Thompson: