Follow-up to the video:  The last U. S. national landslide risk assessment was done in 1982 by the USGS – before GIS and computerized mapping were available. This was at a small map scale – not sufficiently detailed to make decisions about single sites.  A decade ago, Congress authorized the USGS to set national policy to minimize landslide risks. The USGS estimated the cost at $25 million per year; the National Academy of Sciences (NAS) estimated it would cost $50 million. Congress authorized $2.5 million, which has slowly grown to $3.5 million – about 1/10 the value of 17 homes that went down the cliffs at Laguna Beach, California, in  In 2010, following devastating landslide losses in western North Carolina, 6 state geologists set out mapping landslide hazards in the state. In 2011, the newly elected Republican legislature cancelled funding – and five of them were laid off. They were "suppressing business and interfering with peoples' property rights."

Next on the agenda: CLAYS: Where it's all happening!

Secondary Minerals: the Clays These are SHEET SILICATES composed of stacked tetrahedral layers and octahedral layers ( = silica sheets and alumina sheets). These can be stacked in a ratio of 1:1 or 2:1. In most real clays, minor Al for Si substitution in the tetrahedral layers gives them a small (-) net charge The 2:1 clays are most typical of areas with limited water availability.

These clays can ALSO be either DI- or TRI-octahedral: e.g., Kaolinite is DIoctahedral - only 2/3 of octahedral sites are occupied, by trivalent (+3) cations - like Al +3, Fe +3 ; Mn +3, Cr +3, B +3 etc., can also fit here. xx x = M +2 if red dots instead represent other divalent cations TRIoctahedral clays have all three sites occupied, but by divalent (+2) cations. So, the net charge for three octahedral sites remains at a total of +6. TRIoctahedral clays have all three sites occupied, but by divalent (+2) cations. So, the net charge for three octahedral sites remains at a total of +6.

A clay with a CEC of 10 means it can potentially hold 10 meq of cations loosely on and/or in its structure per 100 grams of clay.

xxx 4M +++

The BIG FOUR:

Artichokes, asparagus and rhubarb are among the very few perennial vegetables.

Sulfur 4. Sulfur (S)

Next: Mass Wasting: It's not just in Cotter Union on Friday Night!