APPLICATION OF STRUCTURAL SUCCESSION TO CHARACTERIZATION OF THE BOHEMIAN FOREST TECTONIC DOMAIN AND ELUCIDATION OF GEOLOGICAL HISTORY IN THE CENTRAL-EUROPEAN HERCYNIDES, WESTERN CZECH-REPUBLIC

The successions of observed structural. features in (i) the Domahlice crystalline complex, (ii) the adjacent (Upper Proterozoic) gneisses and (iii) the Moldanubian assemblage of the Cesky les (Bohemian Forest) Mountains correspond and can be integrated into a regionally-expressed deformational sequence. This sequence characterizes the Bohemian Forest tectonic domain in the Central European Hercynides of western Bohemia and both its structural ''fingerprint'' and geological evolution differ from those of both the adjacent Marianske Lazne and the southern Fichtelgebirge tectonic domains. The repetition of recumbent followed by upright structures is interpreted as the result of a multi-orogenic history as is the repetition of crustal heating associated with horizontal tectonism. Juxtaposition of the Moldanubian and the Upper Proterozoic gneiss assemblages with the Domahlice (Tepla - Barrandian) complex took place before the formation of the first recognized folds (two sets of intrafolial folds), the associated schistosities and regionally-expressed medium-pressure Barrovian-type metamorphism, all of which are considered to represent activity during early phases of the Cadomian episode. There were two further phases of fold formation prior to early Carboniferous horizontal tectonism that led to the development of a Hercynian nappe pile and another phase of medium-pressure metamorphism. This metamorphism was expressed as a Barrovian-type zonal pattern in the cover rocks of the southern Fichtelgebirge domain in the Saxothuringian zone whereas in the previously metamorphosed rocks of the Bohemian Forest domain it resulted in mimetic recrystallization associated with foliation transposition. There, in the basement, the earlier-formed isograds and zones remained extant but there were local reversals in the order of zones caused by continued horizontal tectonism. A subsequent change from recumbent to upright structures together with a low-pressure thermal overprint and the emplacement of granitic masses in late Carboniferous times are linked to collision, locking, uplift and transcurrent movements in the later stages of the Hercynian orogenic episode. The large body of new data relating to observed structures and the evidence for successive development of structures not only permits the characterization of the Bohemian Forest tectonic domain and the elucidation of its geological history, but also forms a basis for (1) correlation with, and discrimination from, other tectonic domains, (2) understanding the observed polymetamorphic mineral growths and pattern of metamorphic isograds, (3) interpreting isotopic data that reflect multi-episodic disturbance and (4) placing constraints on regional interpretations of Hercynian tectonism. It represents a reference compilation for future studies of structural stratigraphy and metamorphic mineralogy, with the integration of local structural successions into a domain-wide deformational sequence being comparable to the integration of local stratigraphical successions into a regionally applicable stratigraphy that is an essential prerequisite to stratigraphical correlation.