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5,500’ Snow Line AK Hike


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Just back from an epic hike in the Talkeetna Mountains after a recent storm passed through. The snow line was at 5,500 feet and at this time of year the snow is referred to as termination dust because it will stick in the higher peaks foreshadowing winter’s arrival. I have enough confidence now to name some of the fossils I have encountered on these hikes and would like any corrections on IDs if I misidentified them. The background geology I gleaned from Geological Survey Professional Paper 432, Upper Cretaceous (Campanian and Maestrichtian) Ammonites From Southern Alaska. 


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An early morning start to take advantage of the spectacular weather. 


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Castle Mountain, volcanic deposit which overlays the fossil bearing layers I will be hiking through.

 

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The Wrangell Mountains in the distance overlooking the Copper River Basin and Talkeetna Mountains in the foreground. 


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Landed a ridge and tied down multiple times as even though good weather was forecast I need to have the plane where I left it so I can return home. 


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The fossils on this trip are in the Matanuska Formation, specifically in member 3 and divided into two faunal zones. The lower, Inoceramus schmidti zone and upper, Pachydiscus kamishakensis zone. I believe this is a Pachydiscus sp. ammonite and have seen these before. 

 

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Many of the concretions contain fossils and locally abundant. Having said that it was many miles hiking before a came across an intact ammonite. 


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Bits and pieces to look at and ponder. 


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Canadoceras sp. but so broken could have been a heteromoph and a completely

different ammonite species. 


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I mentioned the good weather for this trip and here is an example of what a storm can do. Normally you do not see what the silt stone looks like in un-weathered condition as it take quite an erosion event to expose the rock from the overburden. The preceding week had some heavy precipitation with this area obviously receiving enough to cut down to the bedrock. All the small gullies I crossed on this hike were also affected by the recent run off and snow at the higher elevations. 

 

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This is at the base of the silt layer where it is overlain by the volcanic rock. The Dall sheep use the steep gullies and cliffs as escape habitat from predators. 

 

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Kobuk, (my dog) was interested in the sheep and I recalled him so as to leave the ewes with their lambs to their solitude. 

 

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Continuing on to my objective where I saw what looked like more silt stone exposure with concretions from the air.

 

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I like this picture which gives a feel for how steep the exposures are. You never know what is on the next one!

 

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Uncommon but I have found some petrified wood in this area. I could not determine what layer this was associated with as it was just laying in the tundra. 


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If you look in some of the pictures you will see numerous caribou trails with this calf cruising by on one while Kobuk and I were having lunch. 


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Caribou can be quit curious at times and this one approached to 12 feet. Notice Kobuk’s paws are ready to go!

 

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Still curious and had to take another look at us. 


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Blue berries are ripe now and a bonus snack while in the mountains. 


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My objective for this hike was this area and exposures. From the air it looked like numerous concretions in the silt stone but turned out to be chunks of conglomerates from the layers above. 


Four and one half miles from the plane so will loop back and check a few more exposures out. 


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The six mile ammonite! Patagiosites alaskensis. 


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The exposure on the right side here immediately caught my attention as I could see concretions.

 

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Getting closer and some more caribou, cow with her calf. More importantly definitely concretions here. 


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Abundant Inoceramus in the float at the bottom of the cliff. Will come back another time to see what might be on the face but need to get new soles on my boots as my current ones are rounded and it’s hazardous when like that climbing that steep of an exposure.

 

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These Cretaceous deposits are very similar to those of Vancouver Island and the Chignik Formation on the Alaska Penninsula. In rereading the professional paper after this hike I got a better understanding of the geology and concretions there. Some of the concretions have thin crystal layers which look a little like shell in cross section. These are described as cone-in-cone concretions and are likely calcite layers which form concentrically in the concretion and their white flash appearance can be seen in the distance when looking shell material.

 

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Looking back from where I traversed can see the Chugach Mountains and recent snow.

 

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Nine miles and almost back to my ride home.

Hope you enjoy as much as I did, what a day!

 

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Wow!  Thanks so much for the tour!  I love that landscape!  Also Kobuk's personality seems to come through in those photos.

 

Don

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Just now, FossilDAWG said:

Wow!  Thanks so much for the tour!  I love that landscape!  Also Kobuk's personality seems to come through in those photos.

 

Don

You are welcome, my pleasure to share. I know this is something you would like to do from your past communication. 

 

Bob

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love your reports.  One of the cool things about this area is (I suspect) that you are the only person out there looking for fossils.  That is pretty special. 

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Fossildude19

Excellent report and finds!

Scenery, quite, wildlife, fossils, and wide open spaces.  

Doesn't get much better than that.  :) 

Thanks for posting. 

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1 hour ago, Nimravis said:

As always, a great write up and stunning pictures.

Thanks it was a stunning day. Now raining the day after the trip here. 

30 minutes ago, jpc said:

love your reports.  One of the cool things about this area is (I suspect) that you are the only person out there looking for fossils.  That is pretty special. 

I have seen boot tracks once in 3 years there that were not mine. It is special and on the hunt for more like it. 

8 minutes ago, Fossildude19 said:

Excellent report and finds!

Scenery, quite, wildlife, fossils, and wide open spaces.  

Doesn't get much better than that.  :) 

Thanks for posting. 

You are welcome, fun to share and get input to my tentative identifications of fossils seen. 

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Man, you've got it figured out. I can't imagine a better combination than hills full of fossils, a charismatic dog, high peaks, wildlife, and the freedom of flying

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FranzBernhard

Unbelievable* report and experiences :default_faint:! Thanks for sharing.

*The most stunning thing for me is how to land and start with your plane in that area. Looks like a miracle to me. But I am noticing some really fat tires ;).

Franz Bernhard

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Great report. Thanks for sharing!

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I adore your trip reports.:b_love1:

Sensational stuff. 

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Your Alaskan trip reports are some of my favorites. Not only fossils but a beautiful landscape. I really like seeing the mountains capped in snow in front of more mountains in front of more mountains and then being pretty remote, the lack of people must make a very fun and relaxing day.

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10 hours ago, Jared C said:

Man, you've got it figured out. I can't imagine a better combination than hills full of fossils, a charismatic dog, high peaks, wildlife, and the freedom of flying

Thanks. Alaska is an amazing place as you have described. I feel very fortunate to be able to experience it and happy to share the beauty.

 

6 hours ago, FranzBernhard said:

Unbelievable* report and experiences :default_faint:! Thanks for sharing.

*The most stunning thing for me is how to land and start with your plane in that area. Looks like a miracle to me. But I am noticing some really fat tires ;).

Franz Bernhard

Also thank you. The aircraft, my red and white magic carpet ride allows access to places that would take in this area several days to hike in from the road.

 

6 hours ago, Ludwigia said:

Great report. Thanks for sharing!

Gerne geschehen (I had to Google that)

 

4 hours ago, RuMert said:

Great atmosphere as always:Smiling:

Spasiba (Thank You)

 

3 hours ago, Tidgy's Dad said:

I adore your trip reports.:b_love1:

Sensational stuff. 

Also Thank You. Maybe more to come as getting things together to head to the Brooks Range on the weekend weather permitting.

 

2 hours ago, Top Trilo said:

Your Alaskan trip reports are some of my favorites. Not only fossils but a beautiful landscape. I really like seeing the mountains capped in snow in front of more mountains in front of more mountains and then being pretty remote, the lack of people must make a very fun and relaxing day.

Thanks as well. Living the dream and wanted to share as I enjoy what other show of their fossil adventures.

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On 8/23/2021 at 10:41 AM, Nchapman said:

Such beautiful country!  Looks like an amazing trip. 

Agreed and this trip will be hard to top.

 

On 8/23/2021 at 11:42 AM, Paleorunner said:

Stunning views, Excellent reporting.
Thanks for sharing.

You are welcome, preparing a descriptive trip report helps me to firm up my understanding of the geology and associated ammonites fossils here. 


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Thinking of starting a new thread:

”Fossils You Have Found in the Laundry After a Trip”

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Epic - these "hills" look pretty steep, I know very well how well the camera doesnt clearly show the steepness.

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  • 2 weeks later...
On 8/26/2021 at 1:53 AM, 6ix said:

Epic - these "hills" look pretty steep, I know very well how well the camera doesnt clearly show the steepness.

True, good boots and ice axe are essential in these areas. Your South Island has the same requirements having tromped around there for several weeks in the past. 

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