Marble Pot on the Allotment

[Caveman Ken]

Anyone have any recent knowledge of Marble Pot? Northern Caves says it is blocked but that was published in 1996. It may have been reopened by now? The first pitch has modern P bolts and modern style rigging, so I guess someone thought it was worth the time and effort. Any info gratefully received.

 

[Pitlamp]

Worth looking at Tony Waltham's image of the 1980 collapse of glacial till that blocked it. See page 85 in Cave & Karst of the Yorkshire Dales Volume 1 (2013).

Volume 2 (2017) page 363 gives useful detail of the exact position & nature of the slump.

It was a very big slump so if a club has re-opened it, good effort!

 

[Caveman Ken]

Worth looking at Tony Waltham's image of the 1980 collapse of glacial till that blocked it. See page 85 in Cave & Karst of the Yorkshire Dales Volume 1 (2013).

Volume 2 (2017) page 363 gives useful detail of the exact position & nature of the slump.

It was a very big slump so if a club has re-opened it, good effort!

Thanks it has grassed over now so that the slump looks much smaller.

 

[Alex]

I was down Marble Pot a couple of years back after a quick attempt on Marble sink. It was indeed still blocked then below the first pitch, but there's a bit to explore down there. It looks like you could dig it quite easily, with some shoring, if the on-going passage is where I presumed it to be.

 

[Pitlamp]

Caveman Ken - did you get to the bottom of this conundrum? I suspect from the post immediately above (by Alex) that it's still blocked.

As a matter of interest there are some good images taken in Marble Pot on that DVD which Steve Clark kindly flagged up (see link below). I've never seen any underground images of the place before.

'Caving Memories' / 'Wilky' DVD - anyone recognise this?

I've found a DVD in with our club (Fylde MC) surveys and things. It appears to be a homemade DVD-R with a printed label. 44mins of photo slideshow with background music, no spoken description. There is a Lancaster University Student's Union minibus in it. Does anyone recognise it or the people...

ukcaving.com

 

[Pitlamp]

This is quite informative:

https://www.researchgate.net/figure/2-The-subsidence-sinkhole-of-Marble-Pot-soon-after-its-far-side-slumped-into-a-newly_fig3_319767083

I was out for a run this morning and went past Marble Pot. Scrambled down (carefully!) for a look at the head of the first pitch. Those anchors described by Alex aboveare very similar to the ones that go around the right hand side of GG Main Shaft. Does anyone know the provenance of those in Marble Pot? They're not listed on the CNCC site as being CNCC anchors but they look perfectly OK to me.

 

[Pitlamp]

Also see page 89 (in particular) in this:

file:///home/user/Downloads/2005SinkholesbookCh0408Subsidenceandinducedsinkholes.pdf

 

[ChrisB]

@Pitlamp, that link is to the downloaded file on your on computer. I think it's:

https://www.geophotos.co.uk/karst-engineering/?smd_process_download=1&download_id=582

 

[Pitlamp]

Ta.

This is a picture of the shakehole taken from the NW side (not the usual view). The rock bridge seen in the more normal view from the SE side is visible in the foreground here. The massive crater immediately beyond it apparently didn't exist until the big slump in 1980; the shakehole floor came down to meet the rock bridge prior to 1980. I suspect reopening the PCC 1979 extensions would be no small task. As well as the contents of the crater having fallen down into the known pot, a vast amount of material from the shakehole side (above the top of this view) also went down there.

I'm right glad I wasn't on a trip in there on the day that it went!

 

[Pitlamp]

Here's the more typical view from the SE. Note the rock bridge referred to in the above post.

The actual cave entrance (1st pitch) is behind the fallen log lying at 45 degrees in this view (i.e. far side of the rock bridge). The large ("new") crater seen in the picture above is between the rock bridge and the camera in this view (but mostly out of shot).

The rock bridge can be reached either by descending climbs following the sinking stream (as per Northern Caves V2 description) or by descending the very steep slope on the far side of the shakehole (on the left side of this view).

 

[Pitlamp]

Went down Marble Pot today to look at the feasilbility of reopening it. From careful measurements, compared with both the ULSA and PCC surveys, I think the vertical blockage may be as much as 15 m deep, i.e. both the 2nd pitch and the excavated shaft directly below it (leading to the Tunnel of Love crawl) are likely to be completely full of debris. It may be possible to engineer a less daunting alternative route nearby. But this would probably still require a lot of materials, so if it's a goer the winch meet is the time to get the stuff up there. We may have a play with it this August.

 

[psychocrawler]

No significant change since a trip with Fabian Garvey in November 1980 down the 1st pitch to check out the blockage caused by the huge slump. We also estimated 40 to 50 feet of mud and rocks to shift. Good to see that the shakehole has grassed over.

 

[Pitlamp]

Out of interest there was evidently some sort of plan to try and reopen it in the late 1980s.

Howard Jones, who was then Descent's Northern Correspondent, mentioned it in issue No. 85 on page 8. Nothing seems to have come of this; perhaps the LUSS team concerned decided the job looked too daunting at the time.