Could an iron oxide form of photosynthesis in early life existed 3.8 billion years ago?
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> http://www.newscientist.com/article/mg21729055.100-rusty-rocks-reveal-ancient-origin-of... now:-"Microorganisms that photosynthesize in the absence of oxygen assimilate carbon by using iron oxide (Fe(II)) as an electron donor instead of water. While oxygenic photosynthesis produces oxygen in the atmosphere (in the form of dioxygen), anoxygenic photosynthesis adds an electron to Fe(II) to produce Fe(III).-"In other words, they oxidize the iron," explains Pecoits. "This finding is very important because it implies that this metabolism was already active back in the early Archean (ca. 3.8 Byr-ago).""-
 Read more at: http://phys.org/news/2014-11-life-history-iron.html#jCp-Imagine this. A very complex chemical process in very ancient life. Just popped up by chance, of course.