I've been down P8 again...also a bit about a knife

[ah147]

So I've been down P8 again... I'm too lazy to write a report, basically the plan was to rig a rope of the cresta bypass and this will be the final bit of work to allow diving to S9 in flood conditions. I took some pictures. I'm pretty sure these are the only ones at the exist. At the bottom is a video of a cool "knife" that works better than anything I've seen for allsorts.

Surface support: Jake the dog

Andy placing a bolt

The view as you leave S3

Rift passage between S3-S4

Start of road to S4

Road to S4

Road to S4

Pots to S4

Budgie pot, after S5

Bottom of budgie pot

Road to S7

S6 on left, road to S7 on right following the line

Road to S7

Start of the cresta run, it gets smaller, you can see why I want to bypass

Battle scars from my cylinders from the day before in the smaller part of the cresta run


This is the video about the knife

https://www.youtube.com/watch?v=WnnwsegwniE&feature=youtu.be

 

[jcarter5826]

They are awesome.  But mine is yellow ;-)

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[Tommy]

Great to see some photos of what lies beyond! Thanks .

 

[cavefinder]

Well that saves me getting wet   

 

[cooleycr]

Thanks for sharing, now I can begin to understand the topology a little better which makes reading the previous trip reports a lot clearer (unlike the water!).. 

 

[ah147]

I find the marked difference in type of passage incredible.

Rifty etc from the surface to the end of the rift after S3, then markedly very phreatic. Where it changes is also a very sharp 90 degree bend.

Can any cave scientisty type people tell me if this means anything?

 

[maxf]

I'm no expert but something to do with a vadose zone meeting a phreatic zone/ previous water table level perhaps ?

 

[Goydenman]

Great to see some photos of what lies beyond! Thanks .

I agree great to see what is there THANKS

 

[ah147]

I'm no expert but something to do with a vadose zone meeting a phreatic zone/ previous water table level perhaps ?

Does this mean if I follow the vadose I'll find more cave?

The photo that says "start of the road to S4" is the exact point I'm on about. That's looking to the left in the rift.

Looking ahead st the same point you see this:

 

[bograt]

That does look like an interesting lead, is that flowstone or mud?, its hard to make out, how does it relate on the survey?

 

[Rob]

Be warned, rifty does not mean vadose.

I haven't been beyond S1 nor would i classify myself as "scientisty type", but my assumption is that almost all of the cave formation lower than the base of the proper second pitch is phreatic. Above that is a mixture of vadose and old phreatic. There are some small signs of vadose downcutting in the lower bits, such as in the streamway just below Mud Hall, and possibly in your "Road to S4" photo, but that is incidental to the main formation.

There are numerous examples nearby where rifts close to nothing, and the only (known) way on is a phreatic passage leaving the rift somewhere at 90?. There are also a small few example i know of where this isn't the case (Salmon's Cavern, Night's Templar, etc)... So it may be worth a dig!

For some background, it has been proposed by some scientisty type people that big rift features often act as routes that allow water to drop "early" from their existing development level into lower, more recently active levels. For example the St Valentines old phreatic passage hits South Rift and the Filthy Five and doesn't seem to continue straight ahead but instead drops down +40m into East Canal which at the time would have been very deep phreatic. This method could be proposed for T'Owd Man's Rift, where the clearly phreatic passages of Stalactite Grotto and the one from Christmas Aven do not continue horizontally but seem to drop down in the Rift and head off into Sump 1, 35m lower. In doing this both these examples also change direction by 90? upon leaving the rift...

To my mind, the main question in P8 is whether the water used to flow into S10 and beyond, or whether it always disappeared into S6 as it does now. I've always thought the former, and seeing the small size of S6 in your photo affirms this further. Also the fact that there seems no vadose downcutting in the "Road to S7" photo suggests very little vadose water has flowed back from S9 to S6. Is there vadose downcutting dropping into S10?

One complication to be aware of in the swallets is the mixture of Reef Limestone and the main Massif Limestone. Here's a diagram from P.83 of JSB's thesis:

The Reef is often tilted, with passages along the strike and slanted rifts (T'Owd Man's Rift?). It typically has lots of fossils. The Massif is almost flat with clear bedding planes and fewer fossils. I think it is also often lighter in colour.

If you can identify the boundary in the cave between these two rocks that may improve our understanding of what's going on. From the position and helped by your photos, i'd say that the "Road to S7" looks like it is in the Massif already....

 

[Brains]

I am sensing some confusion over sump naming / numbering.
The normally flooded continuation at the downstream end of T'owd mans Rift is S4
The other 3 are at the upstream end of this passage, at the end of the passage with the crawl from the streamway at Pitch 2, and where the entrance stream sinks in wet weather at the end of that crawl...
Other sumps would be at the end of Sand Passage, under the wall of the passage near the junction of sand Passage connection, and the sink - often choked - just after pitch 2 where the entrance stream disappears in low flow.
From the rarely dry S4 is where ah147 has been exploring onwards and downwards
Sorry for the aside...

 

[Rob]

Brains, but i'm pretty sure there is no confusion, or wasn't. Certainly all the P8 surveys i've seen (including the JSB 2006 one which is downloadable from the Eldon Website below) agree with the naming convention myself and Ash are using.

The upstream sumps (i.e. those in the "Intestines") are more commonly referred to by letter (i.e. Sumps B - E)

http://www.eldonpotholeclub.org.uk/index.php/homepage/club-history/surveys

 

[RichardB1983]

Brains, but i'm pretty sure there is no confusion, or wasn't. Certainly all the P8 surveys i've seen (including the JSB 2006 one which is downloadable from the Eldon Website below) agree with the naming convention myself and Ash are using.

The upstream sumps (i.e. those in the "Intestines") are more commonly referred to by letter (i.e. Sumps B - E)

There are some older surveys that list the upstream sumps as 1,2,3,4, and the sump at the end of T'own man's rift as sump 5.
e.g. http://www.cerberusspeleo.org.uk/surveys/P8.JPG

Even the Eldon one has Sump I, II, III, IV as alternative names of the upstream ones.

 

[ah147]

Brains is correct.

Naming what I term sump 1 onwards is actually a divers convention for ease of reporting in the newsletters that cavers have caught on to.

Traditionally upstream sumps were 1,2,3,4 and my sump 1 was actually sump 5.

Again, lettering of upstream sumps was brought about by divers for ease of reporting.

As the eldon survey is a compilation of surveys, including divers surveys, one would imagine they used the divers naming system.

For future reference I will continue to use letters for upstream sumps and numbers for downstream sumps.

So...Ill try and answer some questions:
1. The photo looking ahead shows a dry piled silt bank. It was dug in the 1960s to a pitch. Before the pitch could be dropped, sump 4 was passed and the dig abandoned. I'm trying to encourage myself that I should take a big bunch of sand bags and a shovel and shovel several tonnes of silt, on my own, beyond a few sumps to finally get this pitch dropped. I imagine the silt has been redeposited as its on a corner of the main flow since it was dug, leaving the mound you see in the photo. On the survey, follow the dry passage out of sump 3 down a long straight rift heading south. Where there is a hard 90 degree turn heading east, the mound of silt continues in the rift southwards.

2. Regards water flowing to S10 previously or always into S6 as it does now...I would also presume it used to flow through to S10. The photo where you see S6 on the left above, water is several meters higher than I have seen it before. That passage closes down to less than 6 inches high in bedrock.

3. It's kind of vadosey between S9-S10 where there is keyhole shaped passage. Other than this, everything beyond the picture entitled "Start of the Road to S4" is phreatic. Don't be *fooled* by the photos which appear to show keyhole shaped passage. It's just silt banks.

4. Lighter in colour sounds like the passage further into the cave. It definitely lightens as you progress further, until you hit a brilliant white pot between S9-S10. The passage in the above photos is also lighter rock than before the sumps, but does contain many fossils. Large ones. Such as the photo here:

This photo was taken in the cresta run crawls approaching S7. The fossil is about 4inches long. There were lots of them.

Judging by the survey and the photo you posted, I would suggest we are definitely out of the reef zone.


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[Brains]

Lovely crinoids - one of favourite fossils
Sorry to stir up comfusion where you hadnt seen any, but not being a diver I am not (was not...) aware of the sump naming convention! Most features get a proper name, but sumps dont seem to get that honour, perhaps naming them things like "Alice, Bob, Crawly, Damp, Eww, Fantastic, Gritty etc" might cause more humour and less bother in a multi-sump system?

 

[ah147]

Lovely crinoids - one of favourite fossils
Sorry to stir up comfusion where you hadnt seen any, but not being a diver I am not (was not...) aware of the sump naming convention! Most features get a proper name, but sumps dont seem to get that honour, perhaps naming them things like "Alice, Bob, Crawly, Damp, Eww, Fantastic, Gritty etc" might cause more humour and less bother in a multi-sump system?

It's not a sump naming convention per say, just seems to have come about this way specifically in P8.

As for sump names, it seems to be up to the discovering diver. Numbers are easy for places where it's more about the dry passage and less about the sump.

There is a report on here where I discovered a sump near sump 10 in there and promptly named it "f*ck that" sump as I was knackered.

 

[ah147]

So I've been again with Rob Middleton and a large carrying team consisting of:
Mark Wright
Darran Jarvis
Jack Dewison
Micheal Mlyniec
Micheal Woodward
Liam Overett (who really enjoyed a 12L cylinder)

We managed to reline half of S9.

Here are a few more pictures:

Rob heading up the crawl after S8. Not fun with lots of gear. This was about 50cm high. Compared to last time I went it's bigger and less steep.

Crawl immediately after S8. This is less than hands and knees size, just.

I like this bit between S8-S9.

Frog between S8-S9. I believe this must have been washed in through S9 inlet as it seemed quite lively and there's a lot of uphill between the normal entrance and here.

Large passage leading to start of S9.

 

[Rob]

Awesome, thanks for sharing the photos.

How come the passage just after S8 is so small, compared to other bits such as the passage heading to S9? Is it a bypass to the main route, with the main way lost in sediment?

 

[Simon Beck]

Good stuff Ash.. You know how to spend your weekends.. spare time etc!