Elements for the Origin of Life on Land: A Deep-Time Perspective from the Pilbara Craton of Western Australia

The “Water Problem”(sic), the Illusory Pond and Life’s Submarine Emergence—A Review

“…Although wet-dry cycling has been around since at least the nineteen seventies as a proposed prebiotic mechanism for polymerizing amino acids [ 9 , 12 , 13 , 14 ], a similar struggle but with RNA led to the re-opening of Darwin’s casket for the resurrection of “pond theory” [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. However, that casket was empty!…”

“…Top-down attempts to mask or muzzle AVT have now been joined by van Kranendonk and colleagues’ [ 31 , 32 ] “bottom up” presentations of geological evidence for AVT’s supposed ‘passing’. The “water problem” is front and center of their argument—a prejudice that harks back to Shapiro’s 1986 isolating assertion: “The enemy is water”!…”

“…[ 40 ]. The van Kranendonk preferred scenario is for a site which has the advantage of “wet–dry cycling and greater chemical complexity (achieved through additional air/volcanic gas-rock, and air/volcanic gas-water interactions, and information exchange between the numerous, chemically variable pools that typify hot spring systems), in addition to the acidic conditions required to form lipid membranes” [ 31 ].…”

“…To gather support for their preferred model, van Kranendonk et al [ 31 ] explore “deep-time” in search of amenable conditions for their “origin of life”. It so happened that a 3.5 billion-year-old, anoxic hot spring setting from the Pilbara Craton (Australia)” revealed “that its hydrothermal veins and compositionally varied pools and springs concentrated all of the essential elements required for prebiotic chemistry (including B, Zn, Mn, and K, in addition to C, H, N, O, P, and S)” [ 31 ].…”

“…To gather support for their preferred model, van Kranendonk et al [ 31 ] explore “deep-time” in search of amenable conditions for their “origin of life”. It so happened that a 3.5 billion-year-old, anoxic hot spring setting from the Pilbara Craton (Australia)” revealed “that its hydrothermal veins and compositionally varied pools and springs concentrated all of the essential elements required for prebiotic chemistry (including B, Zn, Mn, and K, in addition to C, H, N, O, P, and S)” [ 31 ]. Their argument espouses “temporal variability (seasonal to decadal), together with the known propensity of hot springs for wet–dry cycling and information exchange” and suggests that this “would lead to innovation pools with peaks of fitness for developing molecules” [ 31 ].…”