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Showing results for tags 'lava'.
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Hi Guys! I finally cleaned up the last batch of rocks from my papa and grandma‘s estate. I know from my last post that I’m not supposed to get some of them wet but they were filthy so I had to clean them before bringing them into the house. Any feedback you have is appreciated. if you saw one of my previous posts, you’ll know that my grandparents collected rocks in Arizona, Wisconsin and Illinois. Most of these are probably from Arizona. I think the one piece of orangish petrified wood #3 is very cool. I would love to know if any of the other ones are petrified wood. To me it’s sort of looked like a pork tenderloin when I was cleaning it today! Maybe that’s just because I didn’t stop for lunch. Ha ha. It was so fun to spend time looking at each and every one. I have a critter living in one of them. Some sort of insect. I did my best trying to encourage him to get the heck out today using water and air but I might have to pull out the tweezers tomorrow! Thanks for looking and have a great week…
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I have been thinking about going to Iceland for quite a time, but Covid has made travelling a bit complicated, so when everyone was finally fully vaccinated, we decided to hit the road. We were told that June is actually one of the best months to visit Iceland – with the summer (which over there starts in April) in full swing, with crazy 15 to 20 degrees C. Well… we feel super special, as THIS June was actually the coldest in 45 years, so … But, you’ll see what it looked like on pictures. We landed in Keflavik, and after a short stop to get the Covid test result, we started the trip around Iceland. The first thing we saw was the lava flowing from the newest volcano on Iceland – Geldingadalir. Basically, Iceland’s landscape is quite uniform, as the whole island is covered with lava, with very little vegetation. It has a lot of geothermal fields, sulphur springs, hot springs and lakes of course – waterfalls (app. 4500). There are several different types of waterfalls – some are famous because of the volume of water others, because you can actually walk behind them Yet another type is the so-called lava waterfall – as the water comes from hundreds of cracks in the lava field: Lava is (naturally) one of the main attractions in Iceland – I do recommend going to one of the lava tunnels, which have truly fantastic colours: You have to be careful, as there are lots of icicles everywhere The walls show how subsequent layers were accumulated Lava plays also the main part in the Vestmannaeyjar Island, as during the eruption in 1973, it destroyed ¼ of the town – you can still see the remains of houses: But the island is also home to one of Iceland’s symbol – the puffin birds
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The intrusion of magma and some effects on the fossils
Dimitar posted a topic in Questions & Answers
Hello guys! That was outside of my plans to search in such direction, however a small comment started a big discussion about the possibility to have magma melting the rocks and sealing some fossils. In fact what I was suggesting as simple "melting" seems to be a very complex process or group of processes, that I would suggest to discuss here. So it was already commented, that magma can't really melt other rocks. The temperature of magma is not high enough and it will cool down . Still we see many effects of the magma on the rocks and especially on the sediments and fossils. Here I will try to explain some, so let try to discuss it in the best scientific way . First of all - we talk for underwater sediments. Most likely the intrusion of magma happened when there was still water on the surfice. The main difference between LAVA and MAGMA - these are both the same, however the lava is a magma, that reach the surface and errupt as volcanic activity. But we don't discuss such lava. Most of the time we will see some effects of the magma, intruding near the surface . 1. First effect of the magma - high temperature. Because of the high temperature - the sediments where magma is intruding will be heated. In fact we may not see real melting of these sediments, but because of the high temperature - it will cause these sediments to undergo termal processing which is similar to ceramic production. The water will evaporate. And the clay will harden into very solid hard matterial. 2. The effect of the pressure . Because the magma will erupt from the lower layers - it is under high pressure there. If there is way to the survice it will cause volcanic erruption. It the pressure is not high enough or no such way, the molten magma will try to find any possible space and will fill it. Together with the high temperature - the magma will burn some organic materials and will fill its space. So we may see the exact copy / matrix/ of the organic material but filled and formed by the magma. 3. Chemical processes. Some minerals from the magma may reacct with water or dissolve under hither temperature with water and this may create some kind of magmatic liquid - which would be boiling water with all kind of chemical elements in it. This water may fill the gaps on the bottom, it will be heavier than the normal water and it may create a layer of sediment. 4. The evaporation of water. This is only for a case if water layer is very low and high temperature from underground to evaporate the water, causing all the sediments to form a solid crust. 5. Effects of gases. 6. Cracks - usually the magma will come near the surface through the cracks, so we can see the magma or some products created by magma to fill the cracks in the rocks. The color of such magma or magmatic liquid substances is usually red-brown or black. With all the mention here possibilities I will try to provide some examples of rocks and fossils that I found and to give some explanation, but I should tell that I am not a chemist, I am not geologist. So my explanations are weak. There should be better explanations by the specialists in this field. What is very clear for me: For some very specific rocks and fossils - I may suspect or I recognize some effects of the magma . These are not difficult to recognize. There are many hints to suggest such magmatic activity . I fully understand this is a complex problem and I don't have the background to do such scientific research, I would like to share some observations and to discuss with other participants about such effects and fossil affected by magma actions. First , I will give some examples of rocks, affected by the magma. -
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Here is a cool semi humanite that might be considered a trace fossil someday from the Pinal Geology and Mineral Museum in Coolidge, Arizona. No complaining about the penny for scale. At least they did not use a 1922 plain penny.
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It appears to me that lava flowed over a scallop bed followed by weathering in the surf - i think some mineralization has occured but I cant be positive. Seems a bit rare to me but I don't know anything about it. Any information would be helpful. Could it have come from Hawaii?