Two iconic salt diapirs in the Zagros Mountains in Iran – Karmostaj (Gach) and Siah Taq – are regarded as world-class examples of salt extrusions and are frequently called "salt glaciers". However, our field survey revealed that their glacier-like parts are formed by thick, variegated and deformed caprock, only locally mixed with salt. Caprock is a layer of insoluble residuum that consists primarily of dissolution breccia and gypsum surrounding blocks of non-halite lithologies of the original evaporite sequence. Deformation within the caprock was accommodated primarily by shearing along gypsum-rich zones (gypsum mylonites) that surround subdomains of dissolution breccia and folded and fragmented blocks of carbonates and siliciclastics. Ductile flow in these mylonite shear zones was accommodated by pressure solution-precipitation creep of the lath-shaped gypsum grains. The ductile shearing of gypsum was locally accompanied by increased fluid-pore pressure driven fracturing of the surrounding lithologies. Since the subsurface shape of the salt diapirs is unknown, we present three hypothetical scenarios trying to explain the extrusion process of the studied diapirs and the associated deformation history of their caprocks. The diapiric structures represent either, 1) the remnants of degraded paleoglaciers, 2) advancing salt extrusions, or 3) only slightly reactivated, wide diapirs. To test these hypothetical scenarios, a geophysical survey is required to gain insights into the subsurface structures of the exposed diapirs and salt sheets.

伊朗扎格罗斯山脉的两个标志性盐底辟——Karmostaj (Gach) 和 Siah Taq——被认为是世界级盐挤压的例子，经常被称为“盐冰川”。然而，我们的实地调查显示，它们的冰川状部分是由厚厚的、杂色的、变形的盖层形成的，只是局部混合了盐分。盖层是一层不溶性残余物，主要由溶解角砾岩和石膏组成，围绕着原始蒸发岩层序的非岩盐岩性块。盖层内的变形主要是通过沿着富石膏带（石膏糜棱岩）的剪切来适应的，这些带围绕溶解角砾岩的子域以及折叠和破碎的碳酸盐和硅质碎屑块。这些糜棱岩剪切带中的韧性流动由板条状石膏颗粒的压力溶液-沉淀蠕变调节。石膏的韧性剪切局部伴随着流体-孔隙压力的增加导致周围岩性的压裂。由于盐底辟的地下形状未知，我们提出了三种假设情景，试图解释所研究底辟的挤压过程及其盖层的相关变形历史。底辟结构代表，1) 退化古冰川的残余，2) 推进盐分挤压，或 3) 仅略微重新激活的宽底辟。为了测试这些假设情景，需要进行地球物理调查以深入了解暴露的底辟和盐层的地下结构。石膏的韧性剪切局部伴随着流体-孔隙压力的增加导致周围岩性的压裂。由于盐底辟的地下形状未知，我们提出了三个假设情景，试图解释所研究底辟的挤压过程及其盖层的相关变形历史。底辟结构代表，1) 退化古冰川的残余，2) 推进盐分挤压，或 3) 仅略微重新激活的宽底辟。为了测试这些假设情景，需要进行地球物理调查以深入了解暴露的底辟和盐层的地下结构。石膏的韧性剪切局部伴随着流体-孔隙压力的增加导致周围岩性的压裂。由于盐底辟的地下形状未知，我们提出了三个假设情景，试图解释所研究底辟的挤压过程及其盖层的相关变形历史。底辟结构代表，1) 退化古冰川的残余，2) 推进盐分挤压，或 3) 仅略微重新激活的宽底辟。为了测试这些假设情景，需要进行地球物理调查以深入了解暴露的底辟和盐层的地下结构。我们提出了三个假设情景，试图解释所研究底辟的挤压过程及其盖层的相关变形历史。底辟结构代表，1) 退化古冰川的残余，2) 推进盐分挤压，或 3) 仅略微重新激活的宽底辟。为了测试这些假设情景，需要进行地球物理调查以深入了解暴露的底辟和盐层的地下结构。我们提出了三个假设场景，试图解释所研究底辟的挤压过程及其盖层的相关变形历史。底辟结构代表，1) 退化古冰川的残余，2) 推进盐分挤压，或 3) 仅略微重新激活的宽底辟。为了测试这些假设情景，需要进行地球物理调查以深入了解暴露的底辟和盐层的地下结构。