GeoLog

imaggeo on mondays

Imaggeo On Monday: Geometric Microscape of Agate

Imaggeo On Monday: Geometric Microscape of Agate

“Crazy Lace” is an agate collected in Mexico, which offers great opportunities for aesthetic photomicrography. Here we see the common arrangement of fibers of chalcedony (microcrystalline quartz) in parallel bands alternating with black thin layers of Fe oxides. Polarized light photomicrograph, crossed polarizers and red tint plate. width 5.4 mm. Sample kindly provided by Denise M. Har ...[Read More]

Imaggeo On Monday: A meander in the meltwater valley

Imaggeo On Monday: A meander in the meltwater valley

At the edge of the Greenland Ice Sheet, surface melt releases old layers of dust, that have travelled thousands of years into the ice. Under sunny weather, the dust heats up with radiation, melts the ice underneath, and thus accumulates in tiny potholes and meltwater creeks. However, this photo was taken after a rainy day. The rain triggered increased melt on the surface of the ice irrelevant of i ...[Read More]

Imaggeo On Monday: Contorted Streams on the Gates Glacier

Imaggeo On Monday: Contorted Streams on the Gates Glacier

Annual ridges and troughs (called wave ogives) are formed as the ice of the Gates Glacier (in Alaska’s Wrangell Mountains) flows through a steep icefall. Down-glacier, as the ice melts, the rushing meltwater is funnelled into streams, carving ice canyons as it flows, but ultimately directed by these topographic constraints.   Description by Allen Pope, after the description on imaggeo.e ...[Read More]

Imaggeo On Monday: Ice caves in high altitude karstic areas

Imaggeo On Monday: Ice caves in high altitude karstic areas

High altitude karstic environments often preserve permanent ice deposits within caves, representing a lesser-known portion of the cryosphere. Despite being not so widespread and easily reachable as mountain glaciers and ice caps, ice-caves preserve a great deal of information about past environmental changes and paleoclimatic evolution. Since one of their main characteristics is to have ground-ice ...[Read More]