One comment regarding Lake Manly. Its namesake William Manly was the guide who saved a party of settlers. He walked the entire distance from Death Valley to Los Angeles to get help, then returned with draft animals (only one mule survived), and led the party to safety along the route he had discovered. The distance between Death Valley and LA is about 260 miles, so that rescue was nearly 800 miles of travel--nearly all of it on foot. Everyone who trusted him survived.

Excellent presentations!

Thank you for the descriptions at Death Valley. Your slides are fascinating,

Wow! The sand discussion totally amazed me. Many thanks!!!

Thanks for the vid. I'm a gold prospector in Alaska. If you ever need some Alaskan sand from far out places let me know. I'm always bringing a backpack full rocks home so some sand samples would be know problem be glad to. I would love to see some studies on Alaskan sands. I have found what i think may have been a tektite or volcanic glass it was the size of a baseball the young kid I was with made a joke and pitched it down and it shattered. I never got to see it for more that 10 seconds i was so shocked i had a tektite in my hand i showed him and he broke it:( kids. In 2011 I did find what looks to be a crater of some kind in some muskeg looks like a big drill bit cut a prefect 20 to 30 foot circle it was 20+ feet deep it looked fresh no water in it like the normal swamp ponds in the area it may be overgrown now i never had a ladder to climb down to metal detect it. im guessing bedrock was near the bottom maybe this summer ill try to find that hole again.

Can concrete be recycled? Perhaps crushed and reused (to an aggregate or other useful material)? Very much enjoyed the sand presentation.

they decant the micrometeorites magnetically then melt them down and do a refraction test. jfc, I almost want to memorize the lore of magic the gathering to unlearn the feldspars I just learned. I'm not ready for this level of sand. thank you for your service

16th of a mm. Jesus fucking Christ, just use 132ths of football fields, you broke my freedom measurements.