Wednesday, July 24, 2013

The Ontology of Geology

The notion of ‘ontology’ does not loom large in the science of geology.   In part, this is because geology is wedded to geological history, which, as in the case of its human counterpart, does not self-dissect neatly into freestanding classes of elements.  Further, even synchronically,  the various rocks and minerals don’t form anything like the brilliantly ordered structure of the Periodic Chart of the Elements.

Still, as a finger-exercise, joining our “The Ontology of … “ hit-parade --
-- we try our hand at it here.

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We now return you to your regularly scheduled essay.

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Consider orology:  the study of the structure and genesis of mountains.
Notoriously (this is a chestnut within semantics), the notion ‘mountain’ is vague in two quite different ways:  (1)  what counts as a single mountain, rather than a blip in a ridge;  (2) what counts as a mountain at all, rather than a hill or ‘eminence’.

Similarly, the idea of a ‘continent’ :  (1) what counts as a single continent (is Eurasia one or two?)  (2) what counts as a continent at all, rather than an island or atoll.

Only with tectonics did the notion of a continent  become crisp and interesting.

It was realized later that the true edges of the continents lay  not where the shorelines happened to be, but at the edges of the continental slabs themselves, below sea level.
-- Richard Fortey, Earth (2004), p. 142

The tectonic criteria in hand, it was then concluded that, 200 years ago, theory required a meta-entity, Gondwana, a  supercontinent, consisting of several that are separate today.

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