Individual places and topics of interest
Gibraltar and Jebel Musa coast - wave cut platforms
As well as continuing earthquake activity, another piece of evidence that mountain building is still active, comes from coastal features called wave cut platforms.
Wave cut platforms originate where wave action causes cliff erosion, resulting in retreat of the cliff face and a flat rock platform in front of it that is alternately just above and below the waterline (diagram opposite). This wave cut platform can find itself exposed well above sea-level if either the global sea-level falls; or the land rises. In the case of southern Spain, the latter is the case. The emergent wave cut platform shown in the photo top right of this page (in Morocco across the Straits from Gibraltar) is about 50m above current sea-level. As there is little evidence for global sea-level changes during the Pleistocene in excess of c. 8m, this elevation is caused by the mountains continuing to rise as a result of the Africa-Eurasia plate convergence (Chapter 4). The same can be seen in Gibraltar. The two flat areas on the southern end of the peninsula are actually wave cut platforms. During the Pleistocene, as the mountains have continued to rise, these platforms have emerged in episodic spurts. |
|