Paleo Photography: Natural Pinhole Cameras in Volcanic Vesicles

Paleo Photography explores the possibility that naturally formed vesicles in volcanic rock can occasionally function as extremely long-exposure pinhole cameras. A vesicle provides an opaque cavity, a small natural fracture can provide an aperture, and the inner wall may in some cases retain a persistent light-induced record. Possible recording mechanisms include direct photochemical change, latent chemical or structural change, and electrostatic or trapped-charge effects. The Sun provides the most promising initial target; accumulated solar tracks could preserve information about solar geometry, atmospheric transmission, and potentially Earth’s obliquity. More sensitive surfaces might also retain long-term landscape information. Successive volcanic events and later burial could create records with distinct exposure intervals followed by much longer geological preservation. A non-destructive optical method is proposed for examining the inner surface through the original natural aperture. Similar natural cameras could conceivably form on other volcanic planetary bodies, where preserved optical records might contain information about past illumination geometry or surface conditions. A supplementary PDF reproduces the scientific portion of an unpublished PaleoImagery presentation by the author dated 2 November 2004, which described the core volcanic-vesicle pinhole-camera concept. The scanned pages have been rotated for readability; the original final financial page has been omitted.