Samples and documentation of outcrops and drillings, facies analysis, whole rock geochemistry and radiometric ages have been employed to re-evaluate the Late Carboniferous Tharandt Forest caldera (TFC) and the co-genetic Niederbobritzsch granite (NBG) in the eastern Erzgebirge near Dresden, Germany. The c. 52 km² TFC harbours strongly welded ignimbrites with a preserved minimum thickness of 550 m. Composition of initial fallout tephra at the base of the TFC fill, comprising lithics of rhyolitic and basic lava, and of silica-rich pyroclastic rocks, suggests a bimodal volcanic activity in the area prior to the climactic TFC eruption. The lower part of the TFC fill comprises quartz-poor ignimbrites, overlain by quartz-rich ignimbrites, apparently without a depositional break. Landslides originating from the collapse collar of the caldera plunged into the still hot TFC fill producing monolithic gneiss mesobreccia with clasts ≤ 1 m in a pyroclastic matrix. Aphanitic and porphyritic rhyolitic magma formed ring- and radial dykes, and subvolcanic bodies in the centre of TFC. Whole rock geochemical data indicate a high silica (most samples have > 73 wt% SiO₂) rhyolitic composition of the TFC magma, and a similar granodiorite–granitic composition for the NBG. Based on drillings and caldera extent, a minimum volume of 22 km³ of TFC fill is preserved, the original fill is assumed at about 33 km³. This estimate translates into a denudation of at least c. 210 m during Late Paleozoic to pre-Cenomanian. Telescopic subsidence of the TFC took place in two, perhaps three stages. A possible TFC outflow facies has been completely eroded and distal TFC tuff has not been recognized in neighboring basins. New CA-ID-TIMS measurements on two TFC samples gave mean zircon ages of 313.4 ± 0.4 Ma and 311.9 ± 0.4 Ma; two samples from NBG resulted in 318.2 ± 0.5 Ma and 319.5 ± 0.4 Ma. In addition, for one sample of the ring dyke an age of ca. 314.5 ± 0.5 Ma has been obtained. These ages, together with field relations, allow for a model of a long-standing evolution of an upper crustal magmatic system (~ 5 Ma?), where pulses of magmatic injection and crustal doming alternate with magmatic quietness and erosion. Together with the Altenberg–Teplice Volcanic Complex, located some 10 km to the southeast, the TFC–NBG Complex represents an early post-Variscan magmatic activity in central Europe.

已使用露头和钻探的样品和文件资料，相分析，整个岩石地球化学特征和辐射年龄来重新评估德累斯顿附近东部厄尔士山脉（Erzgebirge）的晚石炭纪的塔兰特森林破火山口（TFC）和共生的Niederbobritzsch花岗岩（NBG），德国。c。52公里²TFC带有高度焊接的易燃物，保留的最小厚度为550 m。TFC充填底部的初始沉降性特菲拉组成，包括流纹岩岩浆和碱性熔岩，以及富含二氧化硅的火山碎屑岩，表明在TFC爆发之前该地区存在双峰火山活动。TFC填充物的下部包括贫石英火成岩，被富含石英的火成岩覆盖，显然没有沉积破裂。源自火山口塌陷领的滑坡陷入热的TFC填充物中，形成碎屑碎屑基质中碎屑≤1 m的整体片麻片中层角砾岩。互生的和斑状的流纹岩浆形成了环状和放射状的堤防，在TFC的中心形成了火山岩体。整个岩石地球化学数据表明二氧化硅含量高（大多数样品的SiO> 73 wt％₂）TFC岩浆的流纹岩成分，以及NBG的类似花岗闪长岩-方解石成分。根据钻探和火山口范围，保留了至少22 km ³的TFC填充量，假定原始填充量约为33 km ³。该估计值转化为至少c的剥蚀率。晚古生代至新生代前210 m。TFC的伸缩式沉陷分为两个阶段，可能分为三个阶段。潜在的TFC流出相已被完全侵蚀，远端TFC凝灰岩在邻近盆地中未被发现。在两个TFC样品上进行的新的CA-ID-TIMS测量结果显示，锆石的平均年龄分别为313.4±0.4 Ma和311.9±0.4 Ma。NBG的两个样品分别为318.2±0.5 Ma和319.5±0.4 Ma。此外，对于环堤的一个样本，其年龄约为。已获得314.5±0.5Ma。这些年龄以及场场关系为上地壳岩浆系统（〜5 Ma？）的长期演化提供了模型，其中岩浆注入和地壳隆起的脉冲与岩浆的宁静和侵蚀交替出现。