Working in limestone cave is easier than granites. In case of granites one need to undestand 1. their age, 2. when did grainite got exposed, 3. An estimate of what sort of processes acted on granites since then. One also needs to understand composition of granite nature of feldspars (K or Na or Ca) tending to understand weathering, their profile and rate. Once the said aspect is understood one can resonably make comment of granite landscape. Need to also list nature of landform assemblage grainte has. it would tell number of processes actively participated in sculpturing the granite plutons.

Thank you for your answer but, unfortunately, it added nothing new to the question.

What new are u looking for?

We have a celar sign of a very old landslide in the regolith on the eastern side of a river valley, while it on the western side the slope is more or less a nubbintype with a well preserved regolith denudatet to make free corestones and granite pillars. The main question is: when could the landslide have been released?

Granitic caves calls are related to the intense fragmentation of the rock. From a fracture system would have generated a valley that subsequently would have been covered by big blocks.

In the Northwest of Spain, near the city of Vigo, there is one of the best examples in Europe. You can see the press release:

http://elpais.com/diario/2011/04/21/galicia/1303381102_850215.html

An paper about this cave can be seen in:

http://ruc.udc.es/dspace/bitstream/2183/6547/1/CA-28-11.pdf

Prof. Vidal Romani, University of A Coruña, is the person who knows the subject in Galicia.

Thank you. First, my ph.D thesis in geology in 1994 was about granitic bedrock caves in Sweden formed by seismotechtonics. I am a personal friend of prof. Juan-Ramon Vidal Romani, and as he did not know anything about the geomorphological history of granitic terrains in Swaziland I took the chance of asking in this media.

I found a discription here: http://www.sntc.org.sz/reserves/malgeology.asp

Ok

Recently there has been quite a bit of work done in Southern Africa on quantifying landscape evolution and erosion rates, mostly using fission track and Be-10 techniques. The bottom line from this work is that the landscape has been pretty much the same for at least 70 My, which tends to rule out a recent uptick in tectonic uplift that had been hypothesized to have happened at about 20 My and 5 My. There has been slow isostatic uplift responding to erosion. Long-term erosion has been constrained by Flowers and Schoene 2010, Geology doi: 10.1130/G30980.1; Scharf et al. 2013 Geology doi: 10.1130/G33806.1; Decker et al. 2013 Geomorphology 190:48-60. Rock uplift has been evaluated by Erlanger et al 2012 Geology doi: 10.1130/G33172.1. Erosion rates using Be-10 have been measured by a number of research groups recently and nearly all come in around 5 +/-3 m/My. (c.f. Chadwick et al. 2013 Geology doi:10.1130/G34721.1). Although the measurements have not been made specifically in your research area, a read of these and articles cited within them will demonstrate that there are generally similar processes at play all across Southern Africa. Enjoy. The landscapes there are wonderful.

Many thanks for w very interesting answer which will give me a lot of thrilling reading.

Dear Rabbe,

The context about granite geomorphology can be provided by the following publications:

Gibbons, C. L. M. H. (1981). ‘Tors in Swaziland’. Geographical Journal, 147: 72-78.

Goudie, A. S., Bull, P. A. (1984). ‘Slope process change and colluvium deposition in Swaziland: an SEM analysis’. Earth Surface Processes and Landforms, 9: 289-99.

Price Williams, D., Watson, A., Goudie, A. S. (1982). ‘Quaternary colluvial stratigraphy, archaeological sequences and palaeoenvironment in Swaziland’. Geographical Journal, 148: 50-67.

Watson, A., Pye, K. (1985). ‘Pseudokarstic micro-relief and other weathering features on the Mswati Granite (Swaziland)’. Zeitschrift für Geomorphologie N. F., 29: 285-300.

I hope this helps.

Best wishes

Piotr Migon

I am positively surprized for the many interesting answers on my question. Now is just the problem for me, retired and without any active institution affilation, to find all these wonderful publications. Thanks.

Dear Rabbe,

I am Professor Raoul Étongué Mayer, geomeorphologist at Laurentian University, Canada. One of the best books in your area of interest or granite landforms is by C.R. Twidale.

Twidale C.R. (1992). Granite Landforms, Elsevier Scientific Publishing Company, Amsterdam, 372 pages

You may also want to see

Buckle C. (1990). Landforms in Africa. An Introduction to Geomorphology. Longman, Hong Kong 249 pages

In case you read French, may I suggest the two following French publications on granite landforms.

Godard A. (1977). Pays et paysages du granite. PUF, Paris, 232 pages

Petit M. (1990). Géographie tropicale. Approche aux études du milieu., Karthala-ACCT, Paris, 351 pages

All the best

Many thanks.!Twidale´s book has been my bible since the first edition from 1982! I met him at Lund University in Sweden in the late 1980s and I cooperat with prof Vidal-romani since several years. I will try to find Buckle (1990).

I am going to introduce you to the most " UNLOVED " Theory in Geology,

and Geo-Physics. It is a combined theory of growth and expansion of

planets.

In one of the prior answers above it stated the age of the granite as being

3029 E 6 years which is roughly 2/3 of the total age of approximately

4544.4 million years. So this begs the questions, why was it buried

deeply under the later accumulated sediments for so long ? Why is it

"suddenly" now exposed at the surface? What happened to all of that sediment?

Where do you put thousands to millions of cubic kilometers of materials

that had to be removed without it just simply coming back and

recovering the granite?

In short, what changed in the evolution of the surface features of Planet

Earth that allowed granite to become exposed in numerous locations

on all the continents, when it is so old, and it was buried for such a long time

protecting it from erosion ?

The answer comes in the limited age of the ocean floors. The oldest

sections of the ocean floors are between 180 million, and 230 million years

old while the oldest pieces of continents can be in excess of 4,000 million

years old. So, why are the ocean floors so young, and why are small

pieces of the continents so very old, and yet they are " just now "

being exposed to the erosion associated with all surface features ?

For roughly 4300 million years the planet gained mass, and materials from

space which successively buried prior layers deeper and deeper, but

about 200 million years ago things inside the Earth began to really heat

up, and materials inside the Earth began, or accelerated their lateral

and vertical movements resulting is segregation, and stratification

where the lighter materials migrate toward the surface, and expand,

while the denser materials move toward the core, and compress.

Since the Earth is made up of 80 % lighter materials, and 20 %

denser materials, there is more growth and expansion internally

than there is compression and densification in the core, so the process

of growth and expansion is gradually accelerating.

The by products of this change in radius and volume is an increase in

the surface area of the planet that allowed the water to pour off the

continents into the newly forming ocean basins. There is a new and

significant difference in elevation between the bottom of the ocean

floors, and the now high and dry continents. There is now some-

where to put all of the thousands to millions of cubic kilometers

of materials that are now eroding off the continents, and

creating new layers to cover the basalt ocean floors.

The erosion and removal of the materials off the continents allows

differential vertical movements of continents that were previously

very restricted in their vertical and horizontal motions, including

spreading laterally to increase the continents surface area is

areas too close to spreading ridges ( The Basin and Range of the

western US ) .

In stead of iso-static equilibrium ( Plate Tectonics ), you now have

iso-dynamic quasi-equilibrium ( Growth and Expansion ). The surface

features of the Earth are constantly in motion and seeking to

eliminate the the differences in vertical and horizontal differences

in mass, pressures and internal, and external forces.

The trouble is that everything is in motion and is changing, so the

results we have now are an instantaneous picture of what it is like now.

It was different in the past, and it will be different in the future.

So Geology is a record of the sequences of changes in the surface features

of the earth due to vertical and horizontal changes in elevations and

distances caused by differential growth and expansion of this

particular Rocky planet as it matures and increases in its overall

dimensions.

The very late ( current ) acceleration in the vertical differences in

the planets surface features, has allowed features buried inside

the Earth for over 3,000 to over 4,000 million years to be

exposed at the surface due to the accelerating erosion and

deposition processes, that were not previously possible in the

prior more static conditions.

My personal theory is that Earth has entered into a transitionary

phase of growth and expansion that will change the planet

from a Rocky Planet, toward a Gas Giant planet.

It is in my opinion an answer as to why the Earth has been able

to have surface life in its oceans and on its land for about the

last 630 million years, and still stay within a surface life

sustaining temperature, and atmospheric pressure range

for such an incredibly long time.

The growth and expansion thins the atmosphere, and the oceans,

it also elevates the land , and it helps keep cooling medium like

glaciers, snow fields and ice fields active and in flux as the

rates of the various changes oscillate in speed and intensity.

In short we owe our existence to a growing and expanding planet.

With out it the temperature maximum of 26 C around 95

million years ago would not have been a peak, it would have

been just a point on a temperature chart that might

have rivaled the temperatures on Venus. ( molten Lead )

When you are enjoying you granite, look up, and think about the

5 to 10 km of materials that were removed by erosion just so

you could look at the nice boulders.

Thank you for a long and interesting answer. This theory demands for a lot of thinking and it is far beyond the mater I deeal with just now. I do like new and unloved theories and I take them seiously. In fact my ph.D thesis in 1994 was build on another very much unloved theory, a theory which fully explained the problems I was dealing with.