Tag Archives: basalt

Sliced thin; time and process recorded in igneous rocks

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This is the second in a series on the geological world under a microscopeThin section of olivine undercrossed nicols showing a kaleidoscope of interference colours

Geologists, it seems, are never satisfied with just looking at rocks from a distance; there is some innate need to wield their pointy geological hammer. Break that rock; give it a good bash! To the uninitiated, this may seem a bit pugilistic, a kind of primal wonton destruction. But a good geo won’t hit rocks just for the hell-of it; a good Geo will be selective. Most of my field assistants and post-graduate candidates needed to be reminded of this. Find something of interest? Before you do anything else, sketch and photograph it; no one will be interested in looking at photos of rubble.

Looking ‘inside’ rocks serves a unique purpose; it allows you to travel back in time, to picture the ancient world, ancient events, outcomes of processes that involve the benign and the brutal, terrifyingly beautiful. Rocks contain memories of all these. And that is why we sometimes break them apart. The optical, or polarizing microscope allows us to unlock these rock memories in a uniquely visual way.  Continue reading

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The Architecture of Connected Holes; A Different Way to Look at the Liquid Earth

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2nd in the Series on Groundwater

lake taupo

We commonly differentiate the solid earth in terms of its architecture, whether it is the foundations of great mountain ranges, or the solidified magmas that underpinned ancient volcanoes.  All rocks, whether layered sedimentary rocks or massive intrusive granites, have unique characteristics that define their physical, chemical and biological make up – their architecture.

WE can also think of groundwater in terms of its own architecture.  The productivity of an aquifer depends first and foremost on its porosity and permeability.  We can use these two fundamental properties to define the architecture of earth materials.

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