Introduction
Pippa Crosby
Since
1961, Oxford University Cave Club has been exploring the limestone karst of the
Western Massif of the Picos de Europa. Several huge cave systems have been
found, explored and meticulously surveyed, and over the years we have pieced
together an ever-expanding picture of the underground complex hidden in these
mountains. Exploration in recent years has focused on "Pozu Jultayu",
also known as "Pozu del Ojo de la Bruja" or "2/7". The
entrance of this cave system was discovered by the 1981 expedition and by 1999
the cave stood at 822m depth, with nearly ten kilometres of passage surveyed.
The cave quickly drops from its mountaintop entrance down a series of vertical
shafts to a streamway at -700m; the streamway then extends horizontally both
upstream and downstream.
The understanding of the local geology we had gained over the years suggested
that exploring the current known limits of 2/7 could reveal not only substantial
amounts of further passage but several possible connections between 2/7 and
other cave systems in the area. Our main aim was to go upstream. In 1999,
exploration had been stopped by a section of deep water.
We planned to return with a Goon suit, allowing someone to walk through the
water without getting wet and rig a tension traverse over the streamway. Our
surveys showed an inviting 2.5km horizontal distance to the neighbouring Sil de
Oliseda and a connection would create a combined system of 20km in length and
nearly 1km in depth. A second possible connection was to Systema Verdelluenga,
an 8km long complex with a downstream sump tantalizingly close to last year's
limit. The worry was that our section of deep water would become the other end
of the sump just around the corner... We also hoped to continue digging at Choke
Egbert, the downstream limit of exploration. A positive dye trace links the
water in the 2/7 streamway to the resurgence at Culiembro, some 2km distant from
and 600m below the choke. If we managed to reach the resurgence-level streamway,
2/7 would be among the deepest known caves in the world. However, three previous
expeditions had already focused attention on this obstacle and made little
progress into the boulder choke.
Alongside the major underground projects, both of which required camping down
the cave for 3 or more nights at a time, we had several smaller projects. These
included the exploration of 10/9, 27/9, F80 and Pozu Jenga.
Summary
The Ario 2000 expedition was incredibly successful, finding some of the most
significant cave passage of recent years.
- Over 1700m of passage found and surveyed in upstream 2/7.
- Second largest chamber in the cave discovered with two streams entering
it, one from the North and one from the South.
- Northerly streamway heads towards Verdelluenga and ends in a sump.
- Southerly streamway heads towards Sil de Oliseda and ends in a boulder
choke.
- Downstream 2/7 has proved too dangerous to dig without scaffolding.