4. Tyrian Cliffs Formation

Tyrian Cliffs Formation

A thick unit of cross-bedded sandstone, formed by long intervals of extensive aeolian deposition. This indicates the presence and persistence of large erg regions that stretched from central Kael, eastward into the much of the Kuru lands, with a very strong regional monsoon wind system that alternated seasonally. The base of the unit is made up of layers lithic wacke, transitioning upwards into a quartz arenite through the vast bulk of the formation. In the Kuru lands, parts of this formation have been uplifted due to faulting, and have been carved into spectacular arches and canyons by wind and rain. In the Veldt, this unit remains primarily underground, and has not experienced any significant uplift or tilting, and so is exposed almost exclusively in the river valleys and gullies where the soft bedrock is easily cut into by the fast moving streams and seasonal thunderstorm floods. Towards the coast, the type-sections for this rock unit are the photogenic cliffs outside the city of Tyre, shaped by wave actions into a labyrinthine mix of fragile spires and sea arches.

Glasswright Member: Arguably the feature the Tyrian Cliffs Formation is most famous for. It is thin unit composed of vitræite (lechatelierite), a glass-like material formed when sand and sediments are flash-fused by exposure to sudden high heat and pressures. This material can be formed naturally in small pockets by lightning strikes, as well as artificially by means of plasma bombardment or nuclear detonations. The widely accepted theory of the formation of this extensive vitræite cap, however, is that a piece of Mayran Impactor, or perhaps a second accompanying body, exploded in a low altitude air burst over the sand sea in the instant before impact. The resulting heat and pressure partially melted the topmost layer of sand, fusing it into glass. This was then followed mere moments later by the rain of debris from the impact to the northeast, burying the glass under layers of ash and rubble. The vitræite has been important not just as a geologic curiosity, but as a cultural touchstone for the Au’Kael of the Veldt. Cultures even predating their arrival would harvest pieces of glass that naturally weather out of the cliffs and gullies, using them for ornamentation. The word used for this material, Malkåch, is not of broader Corvid language origin, and seems to belong to a pre-migration substrate; the word itself believed to mean “earth tears”. But it was the Au’Kael who began to make much more extensive use of the glass material, forming it into ceremonial blades, ornaments, and taking the Glasswright Craft to its peak.