. "Aller Halite Formation"@en . . "stable"@en . "251.9"^^ . "The base of the Aller Halite Formation is normally defined by a sharp downward change from colourless or pink, clear halite to white or grey anhydrite of the Pegmatitanhydrit Formation. The boundary is characterized on wireline logs by a sharp downward increase in velocity and density. The gamma log response to this boundary is variable, although there is commonly no significant downward change. Locally, however, a downhole decrease in gamma values is seen, reflecting the presence of mudstone and/or sylviteenriched halite at the base of the Aller Halite Formation (e.g. 41/25a-l and 49/26-4). Where the Pegmatitanhydrit Formation is locally absent, the Aller Halite Formation rests on the Roter Salzton Formation, coinciding with a sharp downward increase in gamma values, but no significant change in velocity (e.g. 36/26-1)."@en . . "274.4"^^ . . "The top of the Aller Halite Formation is normally marked by a sharp downward change from white or pale grey anhydrite of the Grenzanhydrit Formation to halite, K/Mg salts and local red-brown saliferous mudstones. The boundary is characterized on wireline logs by a downward decrease in velocity and density and a downward increase in gamma-ray values. It is locally less well defined where the overlying Grenzanhydrit Formation is thin (e.g. 49/26-4). Where the Grenzahydrit Formation is locally absent and siltstones of the Bunter Shale Formation rest directly on the Aller Halite Formation, a sharp downward decrease in gamma values and velocity marks the boundary (e.g. 41/25a-1)."@en . . "Aller Halite Formation"@en . "Halite-stone with subsidiary mudstone. Stratified bedrock. Occurs offshore. Deposited during the Guadalupian Epoch - to - Lopingian Epoch (Permian Period) (274.4-251.9 Ma BP)."@en . . "The Aller Halite Formation consists of halite with subordinate interbedded and intergrown K/Mg salts and saliferous mudstones. The halite is generally colourless, locally orange, pink, yellow, white or grey, coarsely crystalline, transparent to translucent, occasionally opaque and moderately hard. The K/Mg salts mainly comprise sylvite and carnallite with rare occurrences of kieserite and are white, pink or red, transparent to opaque, and hard. Mudstones, generally occurring in the upper part of the formation, are redbrown, locally grey-green, soft, amorphous, occasionally hard and locally saliferous and/or anhydritic."@en . "ALHA"@en . "It thickens into the centre of the basin to approximately 130 m, although its depositional thickness is difficult to determine because many sections have been extensively disrupted by halokinesis."@en .