Kilometers of monumental cave systems
Historically strategic geographical position
a multitude of surface-level fossils
Come unearth Socotra's Geography and geology
The Socotra archipelago consists of four islands: Socotra, Darsa, Samha and Abd al Kuri, and two other small islets. The largest and most inhabited of the islands is Socotra, followed by Abd al Kuri, Samha and Darsa. Socotra island can be divided int three main physiographic zones: coastal plains, limestone plateaus and igneous mountain peaks. Limestone plateaus, varying from about ~150m to ~850m AMSL occupy most of the island’s area, followed by coastal plains and low basins, and lastly the jagged igneous peaks of the Hajhir mountains. This varying geography, with topography ranging from sea-level to the Mashanig peak of 1,503 AMSL was created by tectonic processes that are continually in action.
As elaborated by Miller & Morris, the land surface of the Socotra archipelago represents a very old fragment of the supercontinent Gondwana. Within this supercontinent, Socotra occupied a central position close to what are now Africa, Arabia, India and Madagascar. The continental fragment that is now considered Socotra split from the Arabian continental plate roughly 20 - 15 millions years ago, remaining on the same continental plate as Africa, after which it was further pushed away from the African plate by the Red Sea axis and the East African Rift Valley system. By means of this geological history, the Socotra archipelago developed a particular geology observable today.
According to Fleitmann et al. (2004), “Socotra consists of a core of continental basement overlain by a veneer of mainly carbonate rocks ranging in age from Triassic to Miocene.” This veneer of carbonate rocks, or the limestone plateaus the cover most of Socotra island, were formed by the precipitation of carbonate compounds and the accumulation of shells bones and teeth of organisms. As a result, it is quite common to encounter above ground fossils on the expansive limestone plateaus. In addition, the solubility of carbonate rocks in what may be very slightly acidic groundwater and rain have led to the formation of expansive karst topography (cave systems) on the archipelago, amounting to multiple kilometers of cumulative cave systems, with many undoubtedly yet to be discovered.
Literature cited:
1. Miller, A.G. and Morris, M. (2004) Ethnoflora of the Soqotra Archipelago (pp. 8). Royal Botanic Garden, Edinburgh.
2. Fleitmann, Dominik; Matter, A.; Burns, S.J.; Al-Subbary, A.; Al-Aowah, A. (2004). "Geology and Quaternary climate history of Socotra". Fauna of Arabia. 20: 27–44.
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