Gold flake, I've been checking the map again, but for traces of past human activity. There seems to be a lot of both more ancient and very recent sites. You might want to check some spots for stored processed gold or man made gold objects also.The red boxes must be military relics.
These are the associations for most things I mark in red or green.
Red circles/boxes for loose battlefield relics, coins/jewelry or other artifacts of value, from surface down to 1-2 feet deep. Red Xs usually mark deeper loose coins or artifacts of value, caches, cave/tunnel treasure.
Green for archaeological type of hits, including military battlefields and also the non-metallic targets such as flint points, pottery, carved rocks/trees, old foundation sites, etc.
The color is going out on my old computer monitor, so if the color is off, let me know. I hope to soon have the new laptop with external monitor set up in it's place.