Got a sad story about a dendrite. Hillwalker I met had spotted a "fossil fern" on the ridge of Liathach Wester Ross (3456ft) . Told a geologist who said gosh fossil fern in Precambrian sandstone that upends the entire geological record! Hillwalker told me he went all the way back up the mountain but couldn't find the paradigm busting fossil again... I said bad luck and didn't explain about dendrites and sarcastic geologists.
I got interested in geology at about age 7; I collected manganese dendrites on Belt rocks near Missoula, thinking, at the time, that they were fossil plants. Been fascinated with them ever since; I am now a retired geology prof, still fascinated.
Good paper! Really helps to clarify some of the misconceptions about dendrites that people have. Would make a great zoom presentation to certain mineral people groups I’ve described to you in recent times!
Cool Richard. What mineral collector hasn't seen a ton of dendrites?!
Particularly in New Mexico when "Rockhounding" I've opened rocks with vugs of what I call "3-D dendrites" where the branching of black minerals grew upwards into the micro-cavities, some to a few mm! Is that the same thing, do you know? Lots of them here in the serpentines of southern Palawan too.
I have the impression they mostly form in cracks, where they are constrained essentially to two dimensions, but I'd be astonished if they don't sometimes grow into a third dimension if there is space. I'm not sure at all how "feathery" they might get if there was no supportive medium (water, silica gel, mud, etc) and only air, but I bet it is possible. Goethite in Moroccan geodes comes to mind, although the ones I've seen are usually more spiky than feathery, but who knows!
Got a sad story about a dendrite. Hillwalker I met had spotted a "fossil fern" on the ridge of Liathach Wester Ross (3456ft) . Told a geologist who said gosh fossil fern in Precambrian sandstone that upends the entire geological record! Hillwalker told me he went all the way back up the mountain but couldn't find the paradigm busting fossil again... I said bad luck and didn't explain about dendrites and sarcastic geologists.
I got interested in geology at about age 7; I collected manganese dendrites on Belt rocks near Missoula, thinking, at the time, that they were fossil plants. Been fascinated with them ever since; I am now a retired geology prof, still fascinated.
Thank you very much Richard... most informative.. I often wondered but never knew! :-))
Lithiophorite, formula (Al,Li)MnO2(OH)2, is another one that can form dendrites Richard. We have a sandstone quarry near here that produces it.
Cool. Thanks!
Good paper! Really helps to clarify some of the misconceptions about dendrites that people have. Would make a great zoom presentation to certain mineral people groups I’ve described to you in recent times!
Cool Richard. What mineral collector hasn't seen a ton of dendrites?!
Particularly in New Mexico when "Rockhounding" I've opened rocks with vugs of what I call "3-D dendrites" where the branching of black minerals grew upwards into the micro-cavities, some to a few mm! Is that the same thing, do you know? Lots of them here in the serpentines of southern Palawan too.
I have the impression they mostly form in cracks, where they are constrained essentially to two dimensions, but I'd be astonished if they don't sometimes grow into a third dimension if there is space. I'm not sure at all how "feathery" they might get if there was no supportive medium (water, silica gel, mud, etc) and only air, but I bet it is possible. Goethite in Moroccan geodes comes to mind, although the ones I've seen are usually more spiky than feathery, but who knows!
I too wonder, "why not?" when thinking of z-axis formation under suitable conditions. They've got to be out there and probably in profusion.