Jump to content

navigator wall rock composition


tyree

Recommended Posts

  • Replies 12
  • Created
  • Last Reply

Top Posters In This Topic

I talked to a friend recently who was a good friend of Guy and John's (who'd climbed the navigator) and apparently they said "it was fine just a little run out in places"... I didn't ask for more info... I'm a bit more interested in the east pillar but I'm sure it would be a good route too. I hope u crank it laugh.gif

Link to comment
Share on other sites

I havent been up to slesse yet but from what I have heard the north rib is primaraly composed of some granite, NE but is some sort of choss or another so it seems to be a mixed bag. i was hoping to hear it was mostly granite but i guess we'll find out soon. thanks for the info and if yall hear any more id be interested in hearing about it. bigdrink.gifbigdrink.gif

Link to comment
Share on other sites

the east pillar is almost entirely diorite (or whatever the non-granite on slesse is), though the lower buttress toe (to the top of the first pitch per mclane) is granite. my impression is that nav. wall. is similar. northeast butt. is strange, mostly granite down low and on the right (north) side, but the joint with the diorite is right on the crest on the upper half of the route.

 

despite not being granite, the diorite is not pure choss, either; on the e. pillar, it was pretty solid, with lots of edges, but without long continuous crack systems. we did a lot of face climbing to connect small corners, flakes and whatnot. we placed a lot of smaller cams and were happy for the fixed pro. again, nav. wall appears to be similar.

Link to comment
Share on other sites

Sorry. What was I thinking?! My post beginning with "I believe Beckey describes the non-granite rock on NEB of Slesse as "granodiorite" was way off the mark. Apologies to Tyree. Thanks to Crazyjz and Dru for the accurate info.

Edited by Bigwall
Link to comment
Share on other sites

Granodiorite is lumped by many petrologists as "granite". Grain size is independent of mineralogy. Brittleness is dependant on a whole range of factors, as are crack ststems. As a first order assumption, one couls assume that the dioritic rock are probably older, and as such were affected by the emplacement of the younger acidic rocks in such a way to cause more jointing and incipient cracks. These will preclude the development of larger/longer crack systems. This is only an easy model.

Link to comment
Share on other sites

hmm, the rock on the upper half of the NE buttress doesn't look igneous intrusive to me (but i could be wrong), by opposition to the lower part which is some kind of diorite. There are chunks of terranes older than the plutons all over the North Cascades and my not very detailed geologic map of the area shows that part of slesse is some kind of metamorphic rock.

Link to comment
Share on other sites

Slesse consists of a variety of rock types, separated from each other almost vertically. From east to west one goes through Chillwack Batholith then several older rocks ending up with Carboniferous-aged (IIRC) metamorphics on the west side.

 

The Navvy Wall is Chilliwack Batholith granodiorite on the bottom and metamorphic on the top.

 

See photo below...

Link to comment
Share on other sites

357navvy_geology.JPG

 

Flight 810 Buttress at left and South Peak East Face at right

Navvy Wall route line in red

Geologic contacts an approximation

Lithology from personal experience and the geologic map of the area.

The gneiss is really just the most metamorphosed part of the phyllite, the two are really the same geologic unit but the gneiss has undergone greater metamorphism along the Chilliwack Batholith contact, IMHO anyways.

Link to comment
Share on other sites

Roughly speaking the geologic contacts, are at the top of p6 and p15, respectively, if using the belays marked in the Beckey topo. Also the start of the red line that I drew differs from the topo start, which would go up from the snowpatch, to and through the B in Batholith, and then trend right along the ledge that the first geologic contact follows.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...