Fields / Portal
Layers, Systems, and Sequences
Geology reads the history of the Earth from rock. Superposition says older layers lie beneath younger ones, so depth is a clock. A petroleum system needs a source rock, a reservoir, a seal, and a trap, in the right order. And the research about all of it follows a filing sequence: I processed and filed petroleum research for the Illinois State Geological Survey, and following documents through that sequence taught me more about protocols than any course did.
Principles
Superposition
In undisturbed strata, the lower layer is older. Order in space becomes order in time, as in a version history.
wiki: superpositionA petroleum system
Source, reservoir, seal, trap: miss one element or get the timing wrong and there is nothing to find.
wiki: petroleum geologyA filing sequence
Receive, catalog, cross-reference, shelve. The same path a record takes through a database.
isgsParallel and Competing Theories
Readings of the Earth from eleventh- and second-century China, reached independently and centuries before the European formulations.
Zhang Heng’s seismoscope
In 132 CE, Zhang Heng built a bronze vessel that signaled the direction of a distant earthquake by dropping a ball from a dragon’s mouth.
wiki: Zhang HengShen Kuo on landforms
In the eleventh century, Shen Kuo reasoned from marine shells in mountain cliffs that the land had formed from deposited sediment and later uplift.
wiki: Shen Kuo