Blogostratigraphy

This week, I was thinking about how to get back into the flow of blogging, after a long hiatus in which my time and energy were sapped by other projects. First, I considered writing a piece about the exhibit work largely responsible for the hiatus. (I will. Later.) But then I began thinking about that word, hiatus, which is also often used in geological conversations. And I realized that any blog is similar to a sedimentary succession, to such an extent that a new term may be required: blogostratigraphy.

Colourful Paleozoic strata at Valaste waterfall, the highest waterfall in Estonia

Stratigraphy is the study of the arrangement and succession of strata. All sedimentary successions follow a few basic rules, our understanding of which has been gradually refined over the past four hundred years. According to  the principle of original horizontality, sedimentary layers were originally horizontal, while the  law of superposition states that “sedimentary layers are deposited in a time sequence, with the oldest on the bottom and the youngest on the top.” Similarly, the great majority of blogs are composed of horizontal posts, each of which is accreted above the previous one. This current post is like sediment being deposited on the Earth’s surface; if you drill down you will see that the layer below is dated February, underneath that are posts extending back into late 2009, and if you go to the very beginning of this blog you may find yourself somewhere in the Younger Dryas.

Ordovician carbonates in northern Kentucky

Strata are typically laid down in sedimentary basins, low areas in the Earth’s crust (such as Hudson Bay) where sediment is able to accumulate. For sediment to accumulate, it has to be generated, and some geologists like to talk about the “sediment factory.” Large amounts of sediment are typically produced under specific conditions, such as when corals and other organisms are growing great volumes of carbonate skeleton, or when actively-rising mountains are shedding vast quantities of freshly-eroded sand and silt.

When the sediment factory is switched off (as it is, for example, during some sea level changes), then sediments stop accreting in the basin. This hiatus may last years, decades, or millennia. The net effect is that the sedimentary record is not continuous: the record of time provided by sedimentary rocks is of fits and starts, feast or famine. In any one region the rocks may give a wonderful documentation for one period of geological time, but then for the next period there is no evidence whatsoever (we get a much more complete story when we compare several regions). Much modern stratigraphy is focused on recognizing and analyzing the hiatuses, because these can tell us so much about the geological history of basins and continents.

A simple-minded interpretation of the law of superposition might suggest that Steve Kershaw (Brunel University) is older than the Silurian carbonates he has burrowed beneath on the island of Saaremaa, Estonia. Some people will go to extreme lengths to find stromatoporoids!

Blogs are also produced in discrete intervals. No human being is capable of mechanically producing a volume of readable text every day, and a blog is thus a stratigraphic record of the individual’s life. Each post could be considered as a single depositional event. These blogging events are of interest, of course (at least to a few readers), but future blogostratigraphers may well be as interested in the relationship between event and hiatus. How was the blogger able to produce a continuous stream of quality pieces during this interval?  What was responsible for this smattering of drivel? Was this gap related to a a traumatic event in the individual’s life, or did he just wander off and immerse himself in Facebook applications? I imagine a cadre of academic blogostratigraphers, each applying sequence stratigraphic methods to studying the bloglives of the obscure but interesting.

OK, now my idea factory has dried up. Time to think about something else.

© Graham Young, 2010

Next time, maybe I will tell you about my other new blog …