Polished limestone from Marston Magna, U.K. with a calcite vein which runs across the fossil. This piece shows many cross-sections of ammonites (Promicroceras marsdonensis). Jurassic period, approximately 200 million years old.
Amazing Geologist
Chocolate calcite
Resembling an artful edible decoration from some top Swiss chocolatier, these crystals of calcite from the Tsumeb mine in Namibia are coloured by reddish brown inclusions of the iron oxide mineral haematite. Measuring 9 x 9 x 4.3 cm, large speciments of tis nature are very rare.
Loz
Image credit: Joe Budd/Rob Lavinsky/iRocks.com
mikeharrisonfossils WOW!!!😱 This is what fossil hunting ⛏here on the Jurassic Coast of Dorset 🇬🇧 is all about!!! Here I uncover for the first time in nearly 200 million years this imprisoned asteroceras obtusum ammonite. You gotta be real careful “popping” ammonites in this way as they are incredibly fragile!!! This one has a hollow body chamber and it’s as fragile as fine glass!! Got away with it this time…… PHEW!! 😓 #fossil#fossils#fossilhunting#fossilcollection#ammonite#ammonites#jurassic#jurassiccoast#asteroceras#palaeontology#minerals#shells#stones#beauty#charmouth#lymeregis#dorset#geology#dinosaurs#beachcombing#wow#discovery#amazing#stunner#beautiful#paleoart#craft#magic#love#addiction
so the megalodon is most definitely extinct? how do scientists know?
well, the thing about large predators is that they leave an impact on an ecosystem big enough that you can tell they’re there, even if you never observe one directly. in this case, we know they’re definitely extinct because of the behavior of whales! whales used to max out at about 50 ft long and were fast and agile, entirely because of predation by megalodon!
but about 2 million years ago, our whales began to rapidly increase in size until we ended up with real monsters like the blue whale. this pretty directly lines up with the extinction of megalodon, and the removal of the pressure they were putting on large whale populations.
basically, large whales can get away with being gigantic, slow tanks in the oceans today because there simply isn’t a predator big enough to take them on anymore. if megalodon still existed, we would be seeing its impact on whale populations! whales would be smaller, and a hell of a lot more skittish than they are.
everything in a given ecosystem is connected, and you can often get important information about the unknown parts by observing the behavior of other parts of the ecosystem.
“Section of Nautilus, shewing the contour of the septa in the median plane: the septa being (in this plane) logarithmic spirals.” On growth and form. 1917.
What happens when beryl (aka emerald or aqamarine) geologically rots when fluids chemically weather the pegmatites in which they form? The lovely blue mineral known as euclase, named after its easy cleavage, planes of weakness with less bonds in the crystal structure along which it splits easily. It occurs both as lovely prismatic crystals such as these, and fibrous masses in varying shades of blue or light green.
It’s a very special type of gabbroic Rocks that consist mainly of one Ca-Plagioclase minerals (Labradorite).
Orthopyroxene minerals may be exist as very subordinate amount.
Cumulus Texture as a characteristic feature of that type of rocks.
The following figures show Anorthosite rock in hand specimen in which labradorescence shows a blue iridescent flashes, and thin section shows the unique characters of that rock.