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Rock Climbing
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ON THE ROCKS | with Alejandro

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Alejandro Baeza, OGG's Membership Secretary, has been climbing since 1997, starting at the tender age of 17. Since then, with all but a few some gaps during his 20s, he's been a keen climber.  

We asked Alejandro:


What is your greatest climbing achievement todate?

Frendo Spur in Aguille du Midi, in the Mont Blanc Massif of the French Alps.


Where do you most like to climb?

I think the Alps are the place I liked the most although every place has its own charm.


What's your next big challenge?

Mont Blanc - Three Mounts Traverse, although it only has 100 or so metres of technical ice climbing. The rest is a mountaineering route.


Which Climbers do you most admire?

I admire Ueli Steck as an Alpinist, from Switzerland (RIP) and Adam Ondra as a rock climber, from Czechia.


But my heroes are my climbing partners: Ramiro Villanueva from Rosario, Argentina and Gordon Lamb from Yorkshire.






Alejandro treats us to this dramatic seascape: 

the granite cliffs of Bosigran, Cornwall, England.


OGG's Membership Secretary is an accomplished amateur rock climber.  Our November jaunt with our clambering Spaniard is to Bosigran, a large granite sea-cliff near West Penwith at the very tip of the Cornish peninsula. These rocks were intruded 252 - 359 Million years ago in the Permian and Carboniferous periods. Alejandro and his friends are tackling 'Black Slab'. 


The Land’s End Granite is exposed in cliffs along this part of the coast up to 90 m high around the coast of West Penwith and intrudes intensively deformed Upper Devonian rocks of the Mylor Slate Formation. The Cornubian pluton, sometimes referred to as a batholith, consists of two main types of granite: a coarse-grained porphyritic granite and fine-grained granite.  In general, the mineralogy consists of quartz, alkali-feldspar (orthoclase), plagioclase, biotite, cordierite and accessory minerals: monazite, zircon, tourmaline and muscovite. Abundant microgranitoid enclaves, probably formed by magma mingling, are present in both granite types. It is suggested that the Land’s End Granite was emplaced by diapiric ascent of a single magma, accompanied by contamination, differentiation and metasomatism and/or multiple intrusion of discrete magma pulses.

"Bosigran is where many climbers get their first taste of Cornish granite and is perhaps the West Country's best known sea cliff. Bosigran's reputation for superb routes on perfect rock has been widely publicised and the cliff has been at the heart of developments on Cornwall's granite throughout the decades since its first climbs were established early in the 20th century. The position of the cliff is majestic, projecting out into the sea above a remote and rocky cove, and for the most part its base is high above the sea. The cliff's elevation makes it a reliable venue to get something done if the tides are not ideal for accessing other cliffs, or the sea is rough. The routes are simply stunning, predominantly multi-pitch and will interest those looking for long, lower and mid-grade climbs. © UKC

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October 2021

       The precipitous destination for Alejandro this month is Guillemot Ledge, Swanage.


OGG's Membership Secretary is a keen rock climber. and the climb he is sharing with us this October is a dramatic  looking face exposed to the English Channel. In this picture you can see that he's scaling the Portland Stone Formation that forms the sea cliffs west of Swanage, at a spot called called Guillemot Ledge.  The formation is (late/upper Jurassic Period, Tithonian Age (approximately 145.0 - 152.1) in the Titanites anguiformis ammonite zone.  


The Portland Stone Formation was deposited in a marine environment, on the floor of a shallow, warm, sub-tropical sea.  It would have been a proximal location as fossilised wood and other terrigenous and  ferruginous material can be found in the rock.


When shallow water is warmed by the sun, its capacity to carry dissolved gas is reduced; as a result one such gas, carbon dioxide, is released into the atmosphere. Once the carbon dioxide is removed from the water, calcium carbonate precipitates out, tiny particles of which rain down on the seafloor as a blizzard of calcite. The accumulation of millions of tiny carbonate crystals, together with other substrate material, forms a lime mud - a micrite.


The lower part of the formation is a calcilutite, described as a pale brown or grey bioturbated, massive limestone that is composed of more than 50% clay-size, or both silt-size and clay-size, detrital carbonate grains with peloids, sponge spicules, shelly detritus and nodules of chert. The upper part of the formation is a thick bedded, ooidal, shelly calcilutite.  Bioclastic material is abundant towards the top of the formation, with small patch reefs formed by algal mats of Solenopora. You can see the image in the centre panel, above, is showing the detail of the micritic limestone.

"Guillemot Ledge is a large and diverse area that is home to the highest section of cliff along the whole of the Swanage coastline. The big multi-pitch trad routes on the West Face are amongst the most challenging in the south, and almost all of them give tremendous climbing in wild and exposed situations. Across the two areas of the West and East Faces, there is a reasonable grade spread from HS to E6, but Guillemot Ledge should be recognised and treated as a serious cliff where experience of committing and difficult climbing is essential. The rock is usually sound, and the presence of a quarried top on the East Face will calm fears of potential loose finishes when topping-out. A number of the climbs in this area rely on fixed protection from pegs - these should be carefully inspected and backed-up " © UKC

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       SEPTEMBER 2021 


Alejandro is on the famous Isle of Portland, Dorset, England.  


OGG's Membership Secretary is a keen rock climber. In this picture you can see that he's scaling the Portland Stone Formation at an inland site known as 'The Cuttings '(late/upper Jurassic Period, Tithonian Age (approximately 145.0 - 152.1) in the Titanites anguiformis ammonite zone.  The rocks are a micritic (mud-rich) limestone.


The lower part of the formation comprises pale brown or grey bioturbated (the sediment was churned up by organisms before it became a rock)limestone that is composed of predominantly, more than 50%, of either clay-size or both silt-size and clay-size detrital carbonate grains (a calcilutite) with peloids (large visible grains that show no internal structure), sponge spicules, shell material and common black nodular chert (Portland Chert Member).


The upper part of the formation is thick bedded, ooidal, shell-rich calcilutite (Portland Freestone Member). Bioclastic material is abundant towards the top of the formation, with small patch reefs formed by the red alga Solenopora. On the Isle of Portland, the formation is capped by a highly fossiliferous limestone in which the shells have been dissolved out to leave a rock full of bivalve and gastropod moulds (the 'Roach').

"The Cuttings is an excellent and popular inland crag that holds some of Portland's most well-travelled lines. Its easy access, broad spread of grades and sheltered position ensure that there are few days in the year where there won't be someone climbing here. It is an old railway cutting that has left several walls rising directly from a flat quarried base. The walls yield climbing that is mostly sustained and technical in nature, on clean vertical rock. Many of the climbs need lots of finger strength and tenacity, although the profusion of cracks, corners and grooves that bisect the blanker walls give pitches requiring a full range of techniques." © UKC




You can see Alejandro is a good part of the way through his climb at Penmaen Head in North Wales.


The rock he is shinning up is known as the Clwyd Limestone Group. It is a limestone that was formed circa 329-347 million years ago in the Carboniferous Period.

A diverse range of limestone facies (the character of a rock expressed by its formation, composition, and fossil content) with some minor sandstone and mudstone units, and exhibits local dolomitisation (where a limestone comes into contact with magnesium-rich water and converts to dolomite). 


This rock unit marks the start and growth of a carbonate platform along the northern flank of the the ancient Wales-Brabant Massif.  


These rocks would have been deposited at the bottom of a shallow sea, not too far from the coastline. Occasional on-land storms would have washed muds and sandy deposits out, forming the minor sandstone and mudstone units.  


The composition of the limestone is biogenic (produced by living organisms) and detrital (disintegrated-broken/eroded material). They generally comprise carbonate material eg coral and shell fragments forming beds and in some places palaeoreefs.

The location is 44 m OD. 

"Penmaen Head is a relatively recent addition to the climbing on North Wales limestone and has proved to be extremely popular. The crag is made up of a number of walls that have been developed to give single-pitch sport climbs, the majority being in the 6th grade. The rock is generally good and the routes well-equipped allowing plenty of mileage to be gained in a short period. Some of the faces are covered with flowstone and these in particular are well worth stopping off to sample either when travelling past on the A55 or as an escape from the poor weather in the mountains. The crag faces just north of west getting all the afternoon and evening sun that is available. It dries quickly and doesn't suffer from any long term seepage. The Penmaenrhos Wall may give some dry climbing in light rain, and is also sheltered making it a good bet if retreating from the wet and windy mountain crags." (


JULY 2021


Alejandro is scaling The Idwal Slabs, just below the Glyders in central Snowdonia, Wales.

The rock he is clinging to is known as the Lower Rhyolitic Tuff Formation.  It was formed approximately 449-458 million years ago in the Ordovician Period (Caradoc Series).

These igneous rocks are volcanic (extrusive) in origin.  The high silica content of the melt makes the lavas thick and slow-moving, trapping volatile gases. During heightened periods of activity, lavas of this type often form powerful, dangerous and explosive Plinian eruptions and pyroclastic flows.

For those of you who want a bit more technical information the Lower Rhyolitic Tuff Formation can be described lithologically as an acid ash-flow tuff, welded and non-welded, volcanic breccias and rhyolite intrusions.

This extrusive igneous formation overlies sedimentary rocks - sandstones and silty mudstones of Cwm Eigiau Formation. Sitting on top of the Lower Rhyolitic Tuff Formation is another, but distinct unit of volcanic rocks - The Bedded Pyroclastic Formation.

The climbing at this location which is 479 m above ordnance datum is described as:

"Spectacular climbing, set in some of the grandest mountain scenery in Wales; slab-routes galore at every grade. Mainly multi-pitch routes to 160 metres. Must dos for visitors include "Tennis Shoe" (HS), "Suicide Wall Route 1" (E2) and "Hope" (VDiff), all multi-starred classics. Beware of falling sheep." (

Alejandro was climbing "tennis Shoe"

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