• Tuesday-What'sUP October 18 - 07:20 am

During a recent trip to Grand Island in the Munising area, Dave Dalquist snapped photos of some unusual looking sandstone; at least unusual from the typical sandstone you find on the Lake Superior shores, which is more of a reddish stone. The first shot isn't sandstone at all, just plain sand, rocks and leaves but, there again, a bit different than the rocks and sand around the Keweenaw shores. The last two photos show the uniqueness of the Big Lake with her variety of shorelines along her borders.

Nice pictures!

It's really truly amazing how many different formations there actually are around this lake! No wonder everybody loves it.

Not all sandstones around Lake Superior are created equal, as seen in the pictures and eluded to by Mary!!

The Jacobsville is the red sandstone one is used to seeing around the Keweenaw. However, it is also found on Grand Island and forms the cliffs on the west side of the Island. The Jacobsville unconformably lies under the Munising Formation sandstones found in Pictured Rocks. There is also a huge (~500 million years) time gap between the deposition of the Jacobsville and the deposition of the Munising Formation, suggesting that not much happened in this period except for some erosion of the Jacobsville.

A couple of the other big differences is that the sands that make up the Jacobsville most likely came from the Southern Highlands (erosion of the Penokian Mountains in what is now northern Wisconsin) and was deposited in a river environment. The Munising Formation has its source from the Canadian Highlands to the north and was deposited in a complex shoreline/shallow water environment dominated by wave or tidal action (the reason for the huge crossbeds in the Munising and rare in Jacobsville). The other big difference; the Jacobsville is completely absent of fossils, whereas the Munising has a few rare fossils such as early Ordovician cephalopod, conodont, brachiopod, and gastropod fossils.

I hope I haven't bored anyone to sleep so early in the morning with my geologic jargon?? If you haven't figured out already, I love Lake Superior geology!!!! ;-)

Capt. Paul, I found it very interesting. The Pictured Rocks are remarkable, enough so that they successfully charge boatloads of tourists to look at them. Knowing their origin makes them even more interesting.

Bored? Not at all, Cap! Thanks for the info/early morning lesson. :)

Don't know where my post went but I'll repeat it. It's amazing the different rock formations that are around this lake. They're just beautiful.

OOPS! It reappeared!

Nice photo's, I really like the detail of the "trapped" picture.

You have not boated until you take your own boat along that coast on a nice summer day, I used to do it annually from Muinsing to Grand Marais and back. I recommend August due to prevailing off shore winds, I even expierenced driving my boat (slowly) through one of the two natural arches, which you can no longer do because of a rock slide. Putting your bow at the edge of bridal falls will refresh your passengers too!!

Capt. Paul, Zzzzzzzzzzzz!! J/K! I enjoyed it.

Way to go Dave! I liked your (not shown)night photos of the ferry boats too.

Capt Paul, you may join my morning coffee with Lake Superior geology ANY morning! Thank you - it was as fascinating as the pics themselves.

I loved picture 1 before I opened the rest of the story. The geology lesson was very interesting and informative. At first I didn't realize the 3rd picture was sandstone. Its a keeper.

Hey Captian Paul......thanks for all that info....I didn't realize fossils had such names.....city girl here.....Me and my dad used to collect stones and fossils.....I love finding the fossils, they are so interesting.......anyway Thanks!!!!

Capt. Paul: Why'd you send all that rain our way?

Beautiful pictures today! The last one almost looks like an ariel photo.

Just be thankful Marsha it's not all snow!! what is it, 1:10?? If that were the case, you'd have about 8 feet of snow coming!! ;-)

Thanks for all the comments this morning, with the exception of DebS!!! lol. As you can tell, once I get going on Lake Superior geology it's hard to stop. There is just so much to learn and understand about the geology of the area that it truly makes it the most fascinating area to study on Earth. The info earlier was just the cliff notes version of Pictured Rocks geology; there is much more geology to that area than what I posted earlier......

Oh, and I forgot to mention Erica. That last photo is an ariel..... from about 6 feet up!! :P

You mean the second picture is not from the "Trap Rock" river?!

Ariel:
1. A laundry detergent
2. A film by Aki Kaurismäki
3. ahm ... Erica, Capt. Paul, anybody?

Capt. Paul, thanks for the Jacobsville Geology 101 class! Loved it. I just did an art show in Santa Barbara, Calif. The tables and jewelry displays I make are created with Lake Superior driftwood and Jacobsville sandstone! I met several people this past weekend with ties to the UP. One guy, with a very thick Italian accent told me his father was born in the UP......Calumet! Another gal has family ties to the UP and has spent a lot of time up there. Several recognized the sandstone and many others were fascinated with the brief bit of history that I share. It really is amazing when you see the pictures of the way they quarried the stone and then to think it was shipped all over the country and abroad. Who needed gyms back then! That was hard labor for sure. Many famous buildings were made with the beautiful red stone. I must say, I am partial to the multi-colored stones with the fabulous designs.However, these multi colored layers did not bring in the top dollar so it was tossed aside. Our beach is covered with the stone and I just love incorporating it into my pieces. A piece of art in itself. Now that I know more of the history, I will broaden my story that goes with the art!!! Thanks! We truly do have some fabulous history in our little neck of the woods!

Definitely not relating to an area; that would be "aerial", which is what I meant to say... :P

Ariel is the Hebrew name meaning "Lion of God", a satellite of Uranus, or an array-oriented language for the CDC 6400. It's also a spirit who was a servant of Prospero in William Shakespeare's play The Tempest, an Israeli settlement in the West Bank, and a UK car company dating back to 1871. Oh, and I almost forgot. Ariel was the Little Mermaid!!

How's that for an answer to #3 Danbury?? hehe...

Capt Paul, I'm a geology major in college so everytime you throw some information like that out there its always interesting for me to read. Good work.

Good deal Derek; the world can always use more geologists!! What college??

Speaking of geologists, Dr. Nat and I are leaving this Friday for Philadelphia for a week long geologic conference. What's more fun than two geologists?? Try about 6000 together at the same time!! Dr. Nat is actually chairing one of the sessions on earth science education this year. Me, I like cruising around the vendor area to see all the new toys and gadgets out there, just like a man, hehe. One of the talks this year is on the Keweenaw Peninsula and the origin of the native copper deposits; I'll surely attend that one!!

Before I forget for those of you curious, in my gallery I have over 80 photos of UP and northern Wisconsin geology in my "UP Geology" album (talk about a shameless plug!! ;-)

Derek T., I didn't know you were majoring in geology, how do you like it?

ariel: a font choice.

" ariel: a font choice."
Nope, that's Arial!

I stand corrected....but at least you knew what I was trying to say.

Jacobsville sandstone became some landmark Chicago & Boston buildings. In Chicago's great fire, the only things that survived were built of UP sandstone. (sorry, can't remember the architecture reference.) Question: isn't UP black basalt the oldest exposed stone on earth (like, 2 billion years or so)?

FRNash, That was sooooooooo good! Wisht I'd have thunk of it.

The Portage Lake Volcanics, which are made up of basalts and interbedded conglomerates, are 1.1 billion years old. These were associated with the opening of the Mid-Continant Rift. While these are quite old, they are not the oldest rocks on Earth, or even in the UP. The oldest rocks in the UP are associated with the Watersmeet Dome. The rocks there are made up of tonalitic augen gneiss which are around 3.5 billion years old.

The oldest exposed rock on Earth is the Acasta Gneiss in the Northwest Territories of Canada. These rocks have been dated to 4.03 billion years old. The oldest minerals on Earth are tiny zircon crystals contained within the Jack Hills Conglomerate formation in Western Australia which are 4.22 billion years old.

So yes, the basalts in the Keweenaw are very old, just not the oldest. What is really neat is there are features found in the PLV that are being created today in places like Hawaii, such as pahoehoe and aa!! Just to add from earlier, the Jacobsville Sandstone is around 1.0 billion years old and the Munising Formation around 550-500 million years old.

Deb S. (Usedtobeayooper):
I presume you meant the "Trap Rock" river bit.

Cap'n,
Thanks! How serendiptous! My son's on vacation in Hawaii this week, so I sent him your comment, even tho law, not geol., is his thing.

Hrmpf, should've guessed - ok, I'll blame it on your spelling! :)
Thanks, Capt. Paul. Thorough, I'd say. Except for Arielle :D
'Kay, maija - now I'm off to my trusty Webster to find out about what a font choice is ... :)
By the way, little one's nearing, but not there yet - will update you once things get serious.

Not a problem.......

Let us not forget the photographer of these photos who instigated this conversation. Thank you David!