Hi Gang
I did promise to post more on Altycrib and here it is.
The rippled rock in my picture is not a slickenside but the sole or contact
surface of a sandstone bed. As I said, the country rock here is the Devils
Bridge Formation which is alternating layers or sandstone and mudstone.
At the end of the initial northern drive of the Talybont Deep adit is the
horse whim chamber and engine winze. Originally, I mistakenly believed that
the winze was sunk on a fault, it is some distance north of the north lode
which hades in that direction, obviously the winze sunk to pick up the lode
at depth. The winze is not sunk on a fault, its just a slight change in the
angle of the bedding plane plus a quartz string, the winze utilised this
fabric for sinking. Here the alternating beds vary between 1 to 5 cm and dip
south at between 65 and 90 degrees.
If there had been a fault in that area, I have no doubt at all that the
horse whim and engine winze would all be buried under tons of rock, this is
the problem that brought my dig to a standstill.
The north lode has been explored for some distance to the east and
eventually meets another roughly north - south fault that has been followed
for a few feet. Here thee is a small collapse that reveals a rippled sole of
the bedding pane similar to what stopped my dig, but on a much smaller
scale.
My dig follows the north lode to the west from a crossroads with the main
drive inbye from the portal. After about 80 feet the original level picked
up and followed a NW trending lode which was quite likely stoped to some
degree. This is the area of the dig where the rippled rock lies, and the
vein probably had a somewhat pronounced hade. This and the deterioration of
the original timbering have brought down massive chunks of rock. As I said
before, the left hand wall has stull sockets and a shothole indicating that
it is the true left hand wall of the drive, the right hand side is entirely
composed of large blocks that have fallen from the hanging.
If it had been possible to continue my dig in this north westerly direction,
I would have very likely met the Altycrib Fault which may well equate to a
change in direction of the drive shown on the 1888 plans.
I hope that these few notes are of interest.
RF
-----Original Message-----
From: Bernard Moore [mailto:[log in to unmask]]
Sent: 27 April 2009 18:05
To: [log in to unmask]
Subject: Re: Slickensides
Dear Roy,
Not the end of the world... and it doesn't matter - apart from what height
it might have fallen from obviously!!!
My first impression was that it was 'fossilised water ripple marks' - have
seen plenty of these around this part of the world, but they were rather
larger than I have seen. Obviously the p.graph (though good and clear),
doesn't enable any 'striations' to be seen... but I have to say I have seen
some
pronounced slickensides before as well, but not often that rounded and
smooth.
Sounds as if that lump has come from a rather large void! - what is now
anyway!
Regards, Bernard
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