Uplift at many well-documented resurgent calderas started only after completion of the associated ignimbrite eruption, but arching of the large Bachelor caldera in the Southern Rocky Mountain volcanic field, Colorado (USA), began during the eruption. A well-defined arched or domical structure, initiated within thickly accumulating ignimbrite as the caldera subsided, is documented by growth of keystone faults as the caldera filled, rheomorphism and local diapiric mobilization of early-erupted tuff, decreased dips in upper welding zones, and wedging of a late-erupted dacitic phase against flanks of the growing dome. Early subsidence-induced doming may have been triggered by preferential magma draw-down along ring-fault vents, relatively impermeable vesiculation and differential magma buoyancy centrally within the caldera, peripheral loading at caldera margins by landslides and talus from caldera walls, or some combination of factors. Early inception of caldera doming has implications for models of magma withdrawal and residual compositional gradients in non-erupted magma.

中文翻译：

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大型火成岩破火山口沉降引起的早期隆起


许多有据可查的复活破火山口的隆起仅在相关的火凝灰岩喷发完成后才开始，但美国科罗拉多州落基山南部火山区的大型学士破火山口的拱形是在喷发期间开始的。随着破火山口的消退，在厚厚堆积的胶结岩中开始形成轮廓分明的拱形或穹顶结构，记录了随着破火山口的填充，基石断层的生长、早期喷发凝灰岩的流变作用和局部底辟流动、上部熔接区倾角的减少以及晚喷发的英安岩相楔入正在生长的穹顶的侧面。早期沉降引起的隆起可能是由于岩浆沿着环断层喷口优先下降、火山口中心内相对不渗透的水泡和不同的岩浆浮力、火山口边缘的山体滑坡和火山口壁的滑坡造成的外围载荷，或者是以下因素的某种组合触发的：因素。破火山口隆起的早期开始对岩浆撤退模型和未喷发岩浆中的残余成分梯度具有影响。