Geology Reference
In-Depth Information
The “Boring” Billion
The Mineral Revolution
Earth's Age: 2.7 to 3.7 billion years
Australian geologist Roger Buick, a dynamic, wiry firebrand of the early-Earth science
community, once summed up the period sandwiched between the Paleoproterozoic Era
(punctuated by the Great Oxidation Event) and the Neoproterozoic Era (which would see
globe-spanning glaciers dominate the surface and life begin to evolve in interesting ways)
with these stark words: “The dullest time in Earth's history seems to have been the Meso-
proterozoic.”
That supposedly uneventful time, the billion years between 1.85 billion and 850 million
yearsago,isthesubjectofthischapter.Thisvastinterval,dubbedtheintermediateocean(or
more sardonically, the boring billion, by some scientific wits), appears to have been a time
of relative biological and geological stasis. No obvious dramatic transformative events took
place. At first blush, the rock record reveals no epic, game-changing impacts or sudden cli-
mate perturbations. The interface between the ocean's more oxidized near-surface layer and
theanoxicoceandepthsmayhavegraduallygottendeeperanddeeper,butnofundamentally
new life-forms seem to have emerged; nor is it generally thought that many new rock types
or mineral species arose. At least that's the conventional wisdom.
But
boring
is a risky term. I once made the mistake of calling lipids, the rich and varied
class of life's molecules that includes fats and oils and waxes, boring. This remark, made
during a public lecture and in ignorance of the nuances of lipid chemistry, was a mistake
on two counts. First, lipids are, in fact, amazingly diverse. They play all sorts of interesting
roles in regulating life's chemical reactions and crafting its intricate nanoscale structures.
Lipids divide the insides from the outsides of most living things. Without them, life as we
knowitwouldnotbepossible.ThesecondreasonmyremarkwasamistakewasthatImade
itunwittinglyinthepresenceofanattentive,humorlesschemistwhohadspentherentirere-
searchcareerstudyinglipids.Sherightlytookmetotaskandsentmelotsofhighlytechnical
literature to set the record straight. My penance was to read these detailed (and somewhat
boring) tomes.
The point is that
boring
may speak more to our profound state of ignorance than to any
intrinsic dullness. Earth's boring billion may, in fact, be analogous to human civilization's
so-called Dark Ages—that dynamic interval of great innovation and experimentation, inex-
