Geologyhound

I am curious where and when you picked up this rock. The where and when may help identify the type of rock and the process which may be responsible. Obviously a picture is not the best substitute for a rock in hand with a 10 power hand lens. That being said, my initial guesses for type of rock would be shale, basalt or amphibolite. The fact the rock split so nicely makes me inclined to think it is a sedimentary rock like shale which would have planar partings. It is possible for fracture surfaces in other rocks to imitate shale partings at least on a small scale. My guess is the orange material is actually a hydrated iron oxide like limonite and goethite. A limonite/goethite crust would be relatively soft and could probably be rubbed or scraped off. These minerals would be deposited in the fracture or parting when water and iron minerals, or iron sulfide minerals, are present. Basically, when water is under pressure in the pore space of a rock it can hold more minerals and solution. When such water enters a fracture, the pressure drop means water can longer hold as much minerals in solution, and minerals are deposited in the fracture or parting. As I’m sure you are aware, when water freezes it takes up more space. As such “Frost – jacking“ is a major component in mechanical weathering of rocks. Pre-existing features like parting planes in sedimentary rocks or fractures are ideal locations for water accumulation. When this water freezes, it jacks the rock apart. Take a close look at your rock and see if the “crystal shadows” are actually just absence of the orange material. If so, I have to wonder if what you’re looking at is actually more recent ice crystal formation pushing or washing off some of the limonite in the fracture or parting as the rock was finally “jacked“ apart by the ice crystals. Again, without the rock actually in hand, I am guessing.

Air photos can be collected by many different companies or government agencies. As such there is no one central location for the most current air photos of any particular location. I agree with CPT_GhostLight that Google Earth is very useful. Depending on your location, Bing maps (bing.com/maps) may also be useful - especially if you have Birdseye coverage. Over here in the states, various State agencies may also keep online air photo libraries - especially those that deal with soil and groundwater contamination issues - for example the Indiana Department of Environmental Management or the Ohio Department of Natural Resources. The US Department of Agriculture - Farm Service Agency also posts airphotos, but they are still posting for 2021 and 2022 is not yet available. You may need to do some Internet research to see if Spain has an equivalent government agency. For environmental work, various firms offer historical air photo packages for sale. However that is typically on a per-site basis and may cost more than you want to spend for recreational detecting. Environmental Data Resources (EDR) would be one vendor here in the states. Again, all of these sources are simply going to have the most recent air photo available to them. There is no guarantee that is recent enough for your needs. Good luck!

Thanks! I graduated from OSU in ‘93 (geology), so we were there at the same time. Although some of the settings appear to have different names, it looked like there were a lot of similarities between the XLT and the Deus 2 - at least as far as the menu options. Of course I am only judging the Deus 2 by the manual - I haven’t gotten one yet.

Beautiful stone, and you captured the star very nicely! As an Oregon State grad, I may have been in that park (but probably before I got a metal detector...). I have been swinging an XLT for the last 25 years or so and I’m looking to upgrade. I’ve pretty much decided on the Deus II with a 9” coil. I understand the tether and remote connection are issues. However, I noticed you’re an old XLT user, so I wanted to ask what are the main issues you had transitioning to the Deus II?