Manganese Falls
When we went up to Lake Manganese on May 9, 2020 to collect some ore samples[1], we stopped off at Manganese Falls. This is right next to the road, but the only indication of it being there is the sign. Once we stopped, and walked a few feet through the obscuring vegetation, there was a rather abrupt cliff, with a wooden railing, and there were the falls.
The railing was an excellent idea, the gorge that the falls run through is about a 30 to 40 foot vertical drop.
It looks like what we had here was a seam of soft rock (probably conglomerate) running between layers of resistant basalt, and the stream just gouged it out since the end of the ice age.
The pool at the base of the falls wasn’t too big, and had a large rock picturesquely posed in the middle of it.
A lot of the time, the pool at the base of a waterfall is appealing for swimming. I think not so much in this case, though. Not only would it be a long drop off a steep cliff to get to it, we noticed that down at the bottom of the gorge, where the sun doesn’t shine much, there were still icicles.
So, anyway, this is a surprisingly nice waterfall that is easily accessible, and it is worth a visit any time you are up at Copper Harbor.
————–
[1] We were there to collect some samples of manganese dioxide, MnO2, from the old manganese mining prospect. According to the Mindat.org site, Douglass Houghton[2] first identified it as a manganese deposit in the 1830s, and in 1881-1883 the Cambria Iron Company dug out a trench and a short shaft to remove a total of about 1200 tons of ore for assaying and testing, before deciding that it was not sufficiently high-grade for their purposes. So it has been sitting there ever since, mainly just being visited by mineral collectors. I think this picture is of the trench, partially refilled by loose rubble:
This is what I was after. Unlike most of the other people that come to this site looking for attractive or unique minerals, I was just looking for stuff that contained a lot of manganese. Manganese dioxide is a deep blue-black color, and is noticeably denser than typical rocks, nonmagnetic, and slightly electrically conductive. I was able to collect several 5-gallon buckets of the ore without too much difficulty, aside from needing to schlep the buckets about a third of a mile down the not-too-great trail to my car.
Of course, it was mixed with a lot of other rock, mostly iron oxides. I was able to tell them apart pretty well by color, although there were a lot of rocks that were a blend of manganese and iron and so were not so easy to distinguish. A lot of the manganese was also mixed with calcite, which is the white mineral matter in the pile.
[2]Douglass Houghton was the first state geologist of Michigan. He was basically tasked by the state government to examine the Upper Peninsula and determine whether Michigan had been ripped off in the settlement of the Toledo War. Between 1830 and 1840 (when he drowned in a boat accident), he discovered numerous mineral deposits, mainly copper and iron ores. Along with the considerable amount of timber up here, this probably actually made the Upper Peninsula more valuable than the Toledo Strip, so it wasn’t such a white elephant after all. A number of things in the Keweenaw Peninsula have been named after him, including the county of Houghton, the city of Houghton, the Douglass Houghton Hall dormitory on the Michigan Tech campus, and Douglass Houghton Falls, the tallest waterfall in the state at 110 feet.
Comments are closed.
Wow. 1200 tons just to find out it was a dud? Crazy.
Yeah, the mining business is like that. It is surprisingly difficult to figure out just how much ore there is, and its quality, while it is still in the ground.
Have you ever tried getting a “glassy” waterfall photo? I think you set the shutter speed low. We have so little water here in San Diego that I don’t have any opportunities to try it out.