Aspects of the Geologic History of Seawater

Abstract

It would be marvelous if I could unfold before you a grand panorama of the chemistry of the earliest oceans; unfortunately I cannot. We now know a good deal about the limits to the chemistry of the oceans during the last 600 m.y., and about the mechanisms that have kept the composition of ocean water within its rather narrow bounds. We also know something, but a good deal less, about ocean water chemistry during the preceding 2500 m.y.; but there are still no compelling geologic data bearing on the chemistry of ocean water during the first 1000 m.y. of Earth history. There are, however, some interesting alternatives; I would like to explore these, because they do set at least some limits on the chemistry of the most likely incubating medium for the earliest organisms.