More worlds apart!

Before heading out on a day of fieldwork to the Cairngorms, I felt compelled to check Mark's GPS - it is getting seriously addictive! What I saw made me think that it might be quite interesting and thought provoking to compare where he is with our whereabouts today...

The first comparison is that this is the best Google does for the Cairngorms - nothing like the high quality, high resolution images we've been looking at for Iran where not only the roads but vehicles on the roads are visible. However, setting that aside, here we are looking down on mountains which rise to about 1200 metres from the Spey valley which lies at 250 metres. The valley is cultivated or grazed and the lower mountain slopes are forested, some in ancient pine woodland. The snow capped mountains have been carved by glaciers and fashioned by rivers and the weather. Today the temperature was 8 degrees in Aviemore and 3 degrees at the top of the Cairngorm Mountain railway and it was raining!

The other image, shows the desert of south east Iran at an altitude higher than the summit of Cairngorm. Nearby are mountain peaks rising to well over 2000metres.....

There is scarcely a scrap of vegetation visible, the temperature today was 28 degrees and there was wall to wall sunshine. As for the scenery ... well, in common with many deserts, its features are the result of erosion by wind and, surprisingly, water! Everywhere in this part of Iran there is evidence of the effects of water ....from gullies to wadis to the flow lines of sheet wash. When it rains, as it does infrequently,very little of the water released will infiltrate the hard ground. Instead, it will flow off over the surface in torrents carving channels and depositing large quantities of sediment over wide areas.

That fact may account for the linear feature (visible above and to the right) I spotted near the road Mark was on this morning. The resemblance with groynes on a beach is quite striking and I think it may serve a similar purpose in trapping and diverting water and sand which will sweep down the slope and possibly across the road when there are heavy rains. I reckon that water pools up behind the structure and then dries out leaving white mineral salts at the surface. Excess water is diverted away from the road off the end of the structure (bottom right).

Of course, I could be wrong.........