I should be more aquatic myself

You know what? I know I'm going to be eating crow about this for the foreseeable future but I've changed my position about the Aquatic Ape Hypothesis. I just watched the Elaine Morgan
TED talk.

In a nutshell, Elaine Morgan has been arguing for decades (from outside the academic mainstream, which may be important in this case) that the major phenotypic differences between humans and chimpanzees are the characteristics we humans share with aquatic mammals. These include hairlessness and the subcutaneous fat layer which no other primate possesses. She also notes that apes, which are all capable of walking upright when they feel like it, always walk upright when entering the water.

She makes other points which I can't independently verify, that all hairless terrestrial mammals (e.g. elephants and rhinos) have aquatic forebearers (save the naked mole rat, a freak by anyone's measure) and that breath and diaphram control is common to aquatic animals but otherwise unknown in apes. This control gives us the power of speach.

I've read her arguments before and there wasn't anything new in the TED talk that I hadn't heard already. So I googled around a bit to see if she was under-representing the strength of arguments made by her detractors. Most of the arguments I found rely either on the lack of fossil evidence to support the theory, or on logical arguments which don't seem to me to be significantly stronger than those in favor of the aquatic ape.

Evolutionary change can occur when a fortuitous coincidence of environmental pressures with the occurence of a mutation in some population which directly affects the likelyhood of survival relative to those pressures. It also occurs when random mutations which don't affect the likelyhood of survival are also prevalent in the selected population - so it is not reliable to look at a single characteristic and deduce a past environmental pressure. In the long term, traits which advance survival or reproductive success are most likely to survive. However, the rate of mutations is such that this model is never run out to its conclusion. No organism exists, or is likely to ever exist, which is perfectly adapted to its environment at the time we observe it. The disadvantage to survival caused by the occasional appendicitis is not sufficient to cause the next generation to be born without an appendix. The reproductive struggles introduced by the upright human pelvis are likely a more significant challenge to survival than the appendix. But these are accomodated by cultural means, or technology, and have clearly not affected the survivability of the species. In short: the logical arguments made on both sides of the aquatic ape hypothesis so far fail to produce a unique conclusion, only explore what could have been possible.

So. Is it possible that a semi-aquatic hominid existed in our lineage, which could have perservered long enough in the lakes of the East African Rift to adapt some characteristics common to aquatic mammals, although not our nearest ancestors? Logical arguments could be resolved by adequate data from the fossil record.

The hominid fossil record is painfully scarce (relative to other more numerous, longer lasting species). In order to be fossilized, an animal has to die in the right place at the right time. On the savannah, animals are dismembered, desicated, and the bones dry and crack in the sun. There is almost no potential for preservation. Fossil beds from which we understand the record of terrestrial animals come from environments where rapid burial in sediment can take place - lakes and rivers - where we know that terrestrial and aquatic animals gather together. Hominid fossils are also found primarily in lake sediments but this does not really address where they lived, only where they died. Even so, it is not possible from the fossil remains that have been found to determine soft tissue characteristics such as identifying the emergence of a subcutaneous fat layer in our hominid ancestors.

So... Dad... although I am unwavering in my opinion that when discussing scientific theories, "interesting" and "likely to be true" are mutually exclusive - I am no longer hostile to the Aquatic Ape Theory. This has mostly to do with a recently developed appreciation for the scarcity of the hominid fossil record, and therefore the higher degree of uncertainty, than anything else. Now I'm going to the pool.

¡Acuñas!

You might wonder what the locals in rural Nampula province think about a bunch of geologists stomping around their villages asking "Pedras? Aqui? Mais pedras?"

They think we are frickin nuts.

Charnockites.... what?

Hey geoblogosphere, help me out will ya?

I'm a brittle fault person by trade. Now I'm working on a project in the middle crust... slow, squishy and unfamiliar territory. Big mineral grains are nice though... I can identify them in hand sample! They fill a thin section! In most of my field areas, I was identifying minerals primarily through x-ray diffraction. So this is a nice change I suppose.

So here's the scene. The protoliths are a TTG suite - tonalites, granodiorites - metamorphosed at amphibolite facies. Luckily for us, the biotite foliation is pre-syn folding... which means it is sometimes axial planar but often folded. Leucosomes abound; they are solid albite+/-quartz. There are some gorgeous folded meta-dikes of nearly straight amphibole - most likely primary basaltic dykes into the TTG suite - which I am planning to use as strain markers. Here's one in a quarry in the middle of Nampula, Dr. Micheque for scale:

Outcrop here is limited to isolated, steep-sided mounds of rock (inselbergs), it's a common geomorphology in the subequatorial Gondwanaland. There are many inselbergs around Nampula, with completely flat land in between. I have questions about that as well... but I'll save those for another post. Anyway, one of the inselbergs has a unique zone crosscutting it, a networked zone of kspar-qtz-mt veins with a smoky, greenish patchy alteration zone around them (Lee-anne Rudd, Hons 07 and trooper extraordinaire, for scale). What you see looks like wet patches on a jointed rock, but I assure you, at 40° in blazing sun, there is no water here, you are seeing the greenish alteration zones:
Here's a closer look at the thing. The edges of the blocks in the network are sheared, the biotite foliation is curved into the boundaries - implying some rotation of the blocks. (excuse the white chalky patches, which are hammer blows):

Previous descriptions by previous workers called this a charnockite zone. This led me to a big literature search on charnockite (which I never, I swear it, heard of as an undergraduate). I found basically that charnockite is a sparcely defined facies? or rock type? resulting from (rock containing hydrous mafic minerals) + (CO2) -> (rock containing orthopyroxene) + (k-rich, volatile-rich melt). Basically, the idea is that if rocks with a little bit of water in them are flushed with CO2 at high enough temp, the hydrous minerals will dehydrate and the water will cause partial melting of the less refractory minerals, in this case biotite. (More recent work has pointed out that the fluxing fluid need not be CO2, but it needs to be thirsty for water). This fit well with our field observations and we were happy. Until we got home with the rocks. And found no opx, anywhere. Worse yet, our samples from the general background look exactly the same in thin section as the samples from the green patchy alteration zones. No textural difference, no change in mineralogy, even some (scanty, preliminary) microprobe work didn't turn up any difference between the green greasy-looking patchy rock, and the ordinary biotite gneiss. Hmmm.

From a geochemical standpoint, WTF? How can something so obvious in outcrop disappear in thin section? Luckily we have a new secret weapon on board, a metamorphic petrologist who knows THERMOCALC, knows migmatites, would prefer pelites but will help us out anyway.

From a structural standpoint (my standpoint), looky here. We have a network of veins of (I don't know what), at roughly 90° angles. This network occurs in a narrow linear zone about 20m wide. It clearly accommodated the flow of some reactive fluid. And take a look at the meta-basaltic dikes in the blocks in this zone:

Clearly, and this is a new level of wishywash for me, this is a "locus of strain" here in this zone.

Now we come to the question: Falling back on my old friend the Mohr Circle, I would say that 90° fluid conduits are a sign of hydrofracture. Can that be true? Slow, ever so slow hydrofracture in which the opening of joints is accommodated by volumetric strain in the blocks between joints? More importantly, can I use these folded dikes as passive strain markers? And people, what are charnockites? Truly? Do they require CO2, or low aH2O magma, or what? And how do I find out?

* just so you know, that is not my compass. I'm a brunton girl to the grave.
** theres been a lot of chatter lately about appropriate use of the geoblogosphere. Allow me to push the limits here by asking for your opinions on current research.

A Range Front Fault... not so old, maybe?

There are some really beautiful rocks in the Damara Sequence here - hanging wall of the Sole Thrust. Here's a lovely marble. So elegantly foliated. So flat-lying and unsheared. It's part of a strange and complex assemblage - just below it are the strangest diamictites I have ever seen. Could it be part of a Snowball Earth Assemblage? A "cap carbonate"?Just downsection from that, we have this ridiculously gorgeous volcaniclastic fluvial shale... Those are green mudclasts in a purple matrix. But what's this? It appears to be sheared downward to the north. (this sample did not survive transport home, by the way. One must always pack one's own rocks to avert tragedy!! I have a million small chips of purple shale in the bottom of a bucket now.)


Even better/weirder - here's a strange diamictite (further down-section still). The clasts are featureless or ooid-bearing dark blue limestone, generally well-rounded and aligned (e.g. this is not a tillite). The matrix is brownish carbonate and a bit of siliciclastic material (formerly clay). Here you can see the undeformed diamictite in outcrop (below) with a boulder (my boulder) of ductily strained diamictite above. So. Good.
Here's Ben and Jodie on the edge between the horizontal undeformed rocks (e.g. marble, top photo) and the steeply north-dipping, deformed rocks. Much discussion and waving of the arms. Ben is hunting for the perfect sample. Ben has quite a talent for this and will quietly chip at a rock for a long time until it is just right. Jodie: what do you mean, "recent fault"?


Along strike from where we are standing - this. You can see the steeply dipping rocks to the north (downhill) and the flat-lying rocks to the south (uphill). In between? chaos. Ben and I spent quite a while looking up there and trying to figure it all out- but no time to climb that hill!! I will return, I assure you.


Same hill, different vantage point; this time looking about ENE directly along the fault strike:

Retreating to the car, in advance of another rain storm. Ben carried his large sample on his head as he had learned as a child in Zambia. All the way, he kept up a monologue on the fact that African women are the most beautiful and hard-working in the world.
But wait, what's that behind Ben, in the range front? It's the Klein Blasskopf Tufa Cascade. Although I now know the proper terminology, I still prefer "death star of tufa". The interpreted photo below shows the bedding orientation uphill and downhill in the range front, the dashed line shows the approximate surface trace of the fault.


Now I will tell you some "geologic evidences" (as my Italian colleague likes to say):

• this range-front is linear
  
• 2 additional tufa cascades occur along this range front
  
• a pool fed by a spring coming up from below is on top of the tufa cascade
  
• Drag of the folded strata in the range front suggests north-northwest-dipping normal faulting
  
• this normal fault crosscuts low-angle thrusts which characterize the hangingwall - crosscuts Damara bedding and structures.
  

Now for a geochemical argument from a non-geochemist -
All things being equal, ground water flowing upward toward the surface will depressurize. This leads to precipitation of carbonates, for example, in local boreholes. Assuming the ground water reservoirs in the Naukluft are not significantly deep to be geothermal (supported by temperature data at sampling points), depressurization is the most significant effect on solubility. Therefore, a vertical conduit of increased permeability (e.g. a normal fault) may be expected to transmit fluids upwards and thereby cause cementation of its own conduit. This is a one-way process and permeability of the fault will therefore approach ambient permeability with time. Given the propensity of the regional system for A LOT OF CARBONATE MOVING AROUND and the observations that some tufa deposition is active today at the surface (Stone, pers. comm. 2008), I will hazard a guess that a fault conduit would close rapidly rather than slowly. Given that the Blasskrans Normal Fault (yes I am naming this speculative feature now) is an open conduit after a long period of tufa deposition, I suggest a mechanism is necessary for re-opening fluid conduits against the effects of cementation. Possibilities:

1. wild variations in fluid flux
   
2. wild variations in fluid source, carbonate under-saturated fluids dissolve cements
   
3. fault moves and breaks rocks/cements in recent past
   
4. fault is actually a barrier to fluid flow, causing venting at the surface when ground water flowing down hill cannot cross it and gets backed up
   
5. most of cascade are built of surface water and there isnt really that much spring water involved (isotopically testable; preliminary results show significant differences in deuterium ratios between spring and surface waters and rain, Naude, pers. comm. 2008)
   
6. i'm sure there are others....
   

Note that 1, 2, and 3 can all be explained by motion on the fault. Only problem? No documented evidence for tectonic activity in this region (like, all of W Africa) in the last... I don't know... 500Ma give or take a few? Yah. Well, that's not recent enough to explain 1, 2, and 3. So.

My geographer friend and GIS geomorphologist has seen subtle features in the Kalahari which suggest some recent very slow tectonic strain (Eckhart, pers comm 2008). My predecessor in this job, Giulio, has calculated the torque on western southern Africa generated by the zipper-like opening of the East African Rift and predicted north-northwest principle stress across southern Namibia (Viola et al 2005 in EPSL), supported by offshore mud volcanoes along strike-slip faults.

So -no way to link my new fault into this framework yet, but hopefully this demonstrates to the skeptical reader that neotectonics are alive, well, painfully slow and sadly unrecognized in this part of Africa.

Still exploring ideas of post-orogenic relaxation and/or gravity for the Blasskrans fault. Further work is necessary....

Sampling Waters in the Naukluft

For an arid environment, there sure was a lot of water around. Apparently there has been a lot more rain than usual; that is why the area was greener and buggier than anyone had seen in recent memory.

Water resource characterization is actually the main motivator behind this whole effort; my nominal (and periferal) role is to determine what role (if any) ancient or recent faults and fractures are playing in water exchange between the surface and the subsurface.

Most of the water resource extraction in the Naukluft Mountains, and pretty much all of it on the surrounding farms, is accomplished by "borehole". Many have a real working windmills - These usually pump directly into troughs for herd animals (and wild animals) to access.

Although these are often the easiest source for ground water samples, there are a few issues with them. For one, the boreholes are usually lined with some kind of pipe - usually metal - this will affect the geochemistry of the water if it sits in the well a while. Second, they are drawing all the time (whenever the wind blows). This helps with the first concern, as it means water doesn't reside in the borehole too long. However, it means the water level in the borehole might not be in equillibrium with the water level in the surrounding formation - and we want to know the water level of the regional/local water table. If the windmill pumps water out of the well, it takes some time for the water to flow from the rock formations back into the bore holeand during this time, the water level we measure will be too low. This ranger at Zais helped us open the cap under the windmill so we could drop the water level meter down.
We found a few boreholes, such as this one, which had solar panels apparently to drive pumps. This one looked like it was installed to keep a shower ready to go at this outpost on Die Walle farm. Alet is checking the shower tank for water... empty. Kate is getting ready to check the borehole for water... sealed.
The coolest samples come from the rock springs and seeps. Here's Kate suspended by her toes on a slippery algae-covered cliff wall, catching tiny drops of water as they emerge from the rock. We also sampled the surface water such as the stream Kate is trying not to fall into - this will all give a picture of what underground water looks like, what surface water looks like, and how the streams are fed during the dry season... Due to the high visibility of travelling thunder storms, Jodie and the students were able to chase down a few and collect several samples of rain water as it fell out of the sky... this is a great data point to have because it will tell us what the water looks like when it enters the Naukluft. I wish I had a picture of Jodie in a sudden deluge, holding a giant green bucket to shield her head from the huge rain droplets... so pleased with her cold rain sample... but as I was watching from the warmth of the dry bakkie the photos look like a rainy sheet of wet window. hm.

I have to say, Kate was really the workhorse of the water sampling team. She climbed walls and dove to the bottom of clear spring pools. Here she is after sampling the spring-fed creek in Waterkloof. You can see the wall of tufa behind her - more on the tufa deposits in a future post. Anyway it suggests that both surface and groundwater flow through Waterkloof were much greater in the past than today. How far back is the past? We don't know.
Here's Ben in the gorge at Die Walle, entertained by the struggling students climbing the walls to capture tiny drips of water! Behind him in the cliff you can see the reason for this canyon's name, Die Walle: the falls. Standing under that wall, you could see shoots of droplets literally spraying a meter or more out from the wall in the blackened area. A big pool at the bottom feeds the creek running out of the gorge.



We tested the water onsite for dissolved oxygen, pH, temperature, conductivity, eH, and total dissolved solids... Kate and Chris Harris have already started isolating the CO2 dissolved in the water to look at the carbon and oxygen isotopes. She will also analyse the water molecules themselves for hydrogen isotopes. She will also look at the isotope signatures of the rocks in the area, and the carbonate rocks that precipitate in these waters...These will hopefully be able to tell her about the chemical interaction between rocks and water, and possibly help trace the pathways by determining which rocks have more contact with water before it flows to seeps or springs.

Shane and Alet at U. Stellenbosch will find out about those total dissolved solids - what are they? What cations and anions are present, and do they come from rocks, from the rain itself, from biological processes, or human pollution? Does the water get saltier as it flows underneath the ground from the mountains out toward the plane, and the farmers there with their bigger ranches and multiple boreholes?

Pride from U.Nam will be putting it all together, as they say, he will be using MODFLOW to build a 3D picture of the Naukluft groundwater in space and in chemistry.

The big questions we all will work on together:
- If the farmers say some springs are drying up, is that due to over use of a static reservior? Or is there something fundamentally changing in the water system of the Naukluft?
- From raindrop to tap, how does the water evolve and change in chemistry? Is it always safe for humans and animals to use? if the water regime of the area is changing, will this affect the chemistry and safety of the water, as well as quantity?
- How much new water demand can the system support?
- Why are the rocks so damn cool?
Thank you.

The Sole Dolomite (SOUL; DO LO MITE!)

Yah, um, non-geologists might want to take me off your bookmark list for a little while. I think that leaves only testy trifarina to read my blog. Sorry mom, people pictures coming up here at some point! Anyway,

"THE NAUKLUFT" is a big beautiful nappe complex - a klippe on the plains, west of the highlands of Namibia - the last erosional remnant of a mountain range half a million years old. The rocks are even older than that. They are thrusted on top of each other - like a deck of cards spread out on a table and swept into a stack by a southward-moving hand. At the base of the stack is the master fault, along which the rock layers slid, according to previous estimates, something like 50-80km from their place of origin.

This master fault can be seen for miles around the Naukluft - it cuts a sharp, continuous swath across an otherwise convoluted terrane. It's easy to pick out the strange, massive, yellow dolomitic fault rock. Here you see the yellow "sole dolomite" crosscutting the footwall rocks of the Nama Group (gray-blue limestones) and layered brown carbonates of the hanging wall Damara group.

Here's Jodie and Pride on top of the sole dolomite - it has nice sharp contacts top and bottom. In many ways, this fault would be a simple case to study - if the fault rock wasn't made of dolomite (CaMg(CO3)2). Dolomite is maybe the weirdest common mineral there is. Old marine rocks are often made of dolomite - but modern ones pretty much never are. So the theory goes that limestones (CaCO3) which form in the ocean can be altered to dolomite by Mg-rich sea water. Only nobody's been able to make this happen in the lab - so the how/where/why part of the story is still an open question...

Here's an example of a meta-evaporite deposit - a place where dolomite HAS been observed to form in modern environments. Evaporites are salt layers formed when water evaporates (duh) - such as in saline basins in the western US. In the past when the Straits of Gibraltar have been closed by the northward motion of Africa, huge thick layers of salt have been deposited in the Mediterranean sea. This example is from the Nama Group, under the master fault. So a first order question - were these dolomites eroded by fault motion, and ground up to make the sole dolomite? Those white blebs are albite pseudomorphed after evaporite minerals - really cool.
Answer: Um, maybe. probably not. Meta-evaporites are a pretty rare component of those footwall rocks. Ordinary marine dolomites are pretty common in the hanging wall. But either way, there is plenty of ordinary dolomite around... to find its way into the fault zone. One standing hypothesis is that when the nappe complex was moving south, it traveled over the top of a modern (at that time) evaporite basin, and the mineral salts injected like a slurry into the fault. I don't feel too comfy with this hypothesis. For one - evaporites have a lot of minerals in them that aren't dolomite - and the quantity of those minerals reported in the Sole Dolomite by the proposers of this idea is ... a lot different... than what some more recent studies have found. For another... I suspect that if somebody took a closer, more quantitative look at the depth of the fault, the behaviour of slurries, and the deformation of the footwall rocks ... one might find that this is kinematically impossible. But, I confess, I haven't done this.... yet.

The sole dolomite has two main parts - either one might be absent at any given point - but basically there is the "massive dolomite" and the "gritty dolomite". The massive is just that - a slab of crystalline dolomite. No clasts, no banding, no bedding, no structures of any note. Literally featureless. Except for one teeny tiny planar vein of silica that Ben found - and helped me sample - at the Lemeonputz section, which is incidentally, the site of reintroduction of rhinos to the Naukluft Park. The gritty dolomite is composed of amazingly spherical, smooth rounded clasts - of dolomite, mostly, and bits of other things (granites, quartzites, evaporites, etc). Both were once thought to be sedimentary layers, when the thrust faults were thought to be gravity slumps (dip be damned!) back in the 50s-60s when a German group did some structural mapping in the area. Here's Jodie, pointing out the massive dolomite (beige, level of Jodie's head) and the gritty (yellow, where Jodie is pointing). The gritty dolomite crosscuts earlier mylonitic fabrics in the uppermost footwall, as you can see here at the "type locality" outcrop, and yes I got that sample!


There are some amazing features in the gritty dolomite... which i and some of the previous workers believe to be a fluidized cataclasite (regardless of how the dolomite itself was introduced into the fault zone!). Very thin, delicate veins are sharply cut by microfaults... these must also cut the gritty matrix, but they are often invisible away from the veins! This is reminiscent of some features we have seen at Pasagshak Point, Kodiak... which we also didn't make much sense of but I will ask some of the team if they have done any more work on it...

Suspended in the gritty dolomite matrix are large clasts - both of recycled gritty matrix, and also of "massive crystalline" fault dolomite. This one is wrapped or coated in some dense hard mineral - maybe silica? I will be able to tell when I get my thin sections made, when I get my rocks from Jodie, when they are cleared to cross the border... Do you know how many permits and stamps and things you need to move rocks across borders in Africa! I swear they're the only things that can't cross.

As if we needed proof of granular origin and high fluid pressures: gritty dolomite injection features, 12m below the fault in the footwall limestones. So. Gorgeous.



So much more to do here, more to talk about... need to go back to the Naukluft! More geology posts ahead.

Daan Viljoen Game Reserve

Jodie and I took a little break to drive 20km out of Windhoek to the Daan Viljoen Game Reserve. We saw an incredible amount of wild life in only an hour in the park. Here's the entrance gate.

We parked at the lodge in the park and decided to do a 3-km trail because that's all we had time for. We immediately walked into a troop of Chacma baboons. They look quite a bit different than the ones at Cape Point, larger and darker and... not tame. They did not hear us coming and the troup had quite a few young ones, spread around all over the hill picking something to eat off the ground - maybe grubs of some kind? A female gave the alarm when she saw us and a big male immediately moved between our path and the females. He gave us some warning barks and swaggered toward us on his knuckles like a gorilla. We just slowly kept on the path and once our intention was clear, the troup ignored us.

Only literally two minutes after we passed the baboon, we almost walked into this beautiful kudu doe. She was standing dead still behind a tree and we almost didn't see her. You can see she is quite a substantial animal, bigger than a deer and smaller than a caribou. Whatever that means.

No sooner did Jodie say "One rarely sees only one kudu" than we saw the males catching up behind her. They are much bigger and the curve of their horns tells you how old they are. They make 360° at about 2 years of age and 720° by about 6 years.


Across the valley we spotted some oryx (gemsbok) on a hill and on the way out I was able to get a photo:

The best treat on the way out of the park was this wildebeest right on the road. Look at his mane blowing in the wind. No really, click the picture. Experience the beest.

Why no emails?

I don't know how the Guardian managed to get this murky scaryland picture of our beautiful city:

because it DOESN'T LOOK ANYTHING LIKE THAT! This is some photoshopper's impression of the apocalypse or something. But yes those are our Simpson's towers. They are small though.

However, the story from which I pulled that picture is correct, we are experiencing "load shedding", strangely reminiscent of the rolling blackouts Californians will remember when some corrupt bastards undertook to ruin everyone else. This is oddly familiar! Hopefully the party will take some fast action to allow self-generators to sell back to the grid. Because every self-respecting business and many of the universities (not us, of course) are generating their own power for the 2-3 hrs in midday when the blackouts roll through.

The West Coast

It took us a little longer than expected to get out of Groot Winterhoek - don't as me how we lost the trail, but it turns out sometimes you need a trail to get across a river. Anyway we were pretty happy to get across the wheat fields of the Swartland and out to the West Coast. We had a nice breakfast at a cafe in Piketsberg on the way. Finally we made it out to the legendary Eland's Bay which Sila had read so much about in the surf mags. Approaching the beach:
No swell today but perfectly formed tiny waves. There were kids wading around in the tide pools playing with large succulent lobsters. We will secure our crayfishing permits upon return to Cape Town, for sure. The beach at Eland's Baai was purple with shells.
We had a gin & tonic at the Eland's Baai Hotel and waited to see if surf would increase as the tide changed. Not so much. So we hopped back in the beetle to head north to Lampert's Baai, the West Coast's biggest fishing village and last real town. They had a pretty sweet harbour, which cost us R2.30 to enter. That's 33c US. I can't believe the toll-taker guy is collecting his salary everyday. Anyway,
Lampert's is a cool little town, there is a lot of tourism but fishing is still the heart and soul of the place. It was nice to see that people seemed generally employed and happy here. There is a lot of fish packing/freezing work as well. These guys had a pile of either octopus or fish innards - didn't get close enough to tell. What are they doing with them?
Beautiful fresh Snoek for sale. I wanted to get a cooler and bring some fresh fish home, but Sila said no.
Sila wanted one of these, but I said no:
Keeping things fair in the marriage, see?

A few km's south of Lampert's Bay on the extremely bumpy unpaved coast road is a strange little restaurant with walls built of tumbleweeds and brambles (Muisbos = Mouse bush). Muisbosskerm Restaurant is a prix fix barbeque extravaganza of all-you-can-eat West Coast seafood, South African traditional dishes such as the waterblommetjie bredie, and for an additional R75, two lobster tails. Will have to get some waterblommetjies as they taste like artichoke, although Sila wouldn't eat the bredie because of the mutton. He's still scarred over his mom's old ram Rocky that used to beat the crap out of him and Liam. Anyway going to try an artichoke dip or something with the water lilies. You can sit around the braai area and watch the cooking: Or you can sit on the beach and watch the fish prep:
Drinking cold beer or wine. Did I mention it is standard to get a glass of ice to put in your white wine here? No kidding.
From the beach:
Cutting the heads off our tasty lobsters:
Sun going down:

Future guests will absolutely get a visit to Muisbosskerm. Sorry Mom we didn't know about this place when you came to visit.

Groot Kliphuis and the best campsite ever

It was still rainy when we got up the next morning but this was somewhat welcome because we planned a long uphill loop for the day. We set off north on the jeep road from De Tronk but pretty soon took off on a side trail up a steep canyon toward Groot Kliphuis.

The canyon cut across the local geology and awesomely confirmed what I thought was going on in the area. The Groot Kliphuis River runs down the center of a gently south-plunging syncline and here we are crossing out of the eastern limb. You can see the top of the Peninsula Sandstone (without Pakhuis Member?) exposed by erosion. The 'fold zone' is clearly present even if the Pakhuis Member is not. Can't tell for sure if it is there. Above the exposed sandstone surface is the grassy slope of Cederberg Shale. Atop that you can see the sandstones of the Nardouw Fm. - these are very difficult to tell from the Peninsula Fm. in outcrop but a bit more likely to make the strange and wonderful boulder piles we saw along the river.

You can see some parasitic ramp-thrust folding in the lowermost Nardouw Fm. (Goudini Mbr).

We came out on top after a steep climb into the Groot Kliphuis valley. It was really beautiful and the fynbos in early summer bloom looked almost tundra-like. One definitely can tell it gets cold up here in the winter time. The floor of the valley is a thick sandy floodplane deposit and the river running through it was the clearest and most delicious we found.

We never did find the ruins of Groot Kliphuis, unless these oak trees are it. We had a nice hot lunch here under the trees. The sun started poking through.

We lost the trail at the oak trees - or maybe we left it and went on oak-tree-autopilot? not sure. Glad we had the topo although can't say our skills were terrific, too bad I forgot my compass at home. Anyway we made it back to the trail where it winds out of the valley along the headwaters of the Groot Kliphuis River and found ourselves meandering back up stratigraphic section into the Nardouw Sandstone goblinland again:

The river drops down into a deep gorge here, we never got a clear look over the side because by this time we were 10km into our day and getting worried about finding a campsite.
We stopped to take a picture over the gorge though:

We almost camped here at this beautiful pond surrounded by orchids. It was very froggy. We were only about 5km from the parking lot at this point and we knew of one last sandy, flat site along the river so we decided to keep going to see if there was anything better. I was hot and really wanted to swim!

The trail wound away from the river for a little while and I thought I had missed my chance to cool off. The boulders got stranger and I knew we were getting near to the syncline axis where the axial planar cleavage and perpendicular jointing in the Goudini Sandstone is much stronger.
When the river hits the axis of the geologic fold, it makes a 90° turn toward the south. At this turn we found the most beautiful swimming hole, with several braided pools and little cascades between them:

We decided to camp here, figuring we were an hour or so from the car, so we could take a morning dip in the clear water and still make it out to the coast in the afternoon. Here's Sila cooking ravioli in river water:


We found a carnivorous plant! If you look closely you can see it has captured a fly in one of the curled leaves on the left:

Beautiful potholes suggest this can become a torrent during flood season:

A pebble bed in the Goudini is partially eroded to reveal steeply dipping crossbeds in the sandstone underneath. This combination of features is pretty good evidence that the sediments were deposited in a fluvial environment, although it must have been pretty huge and stark compared to todays rivers:


We camped in a sandy spot right above the swimming hole. Too Perfect for words. Spread all the wet clothes from 2 days of rain on the hot rocks and watched the sun go down over the west limb of the syncline (ridge on the horizon). Watched the myriad strange constellations come out through the mesh roof of the tent.

Sun setting over the swimming hole: