Comprehensive field, petrographic, and petrological investigations have revealed, for the first time, the presence of diverse mafic intrusive bodies within the Precambrian basement of the Skoura inlier (Central High-Atlas). These intrusions occur exclusively as massive bodies cross-cutting the lower Ediacaran meta-sedimentary succession. Petrographic observations and geochemical data allow classifying the gabbroic rocks into three distinct facies: gabbro-norite, gabbro, and gabbro-diorite. The gabbro-diorite facies is dominated by pyroxene, plagioclase, and partly altered biotite, with opaques and rare apatite as accessory minerals. Chlorite and sericite represent secondary alteration products. Geochemically, this facies exhibits a tholeiitic affinity and display REEs and trace-element patterns consistent with a mid-ocean ridge (E-MORB)-type mantle source that underwent minor crustal contamination. These features suggest emplacement during the Late Triassic, contemporaneous with the onset of continental tholeiitic magmatism in the region. The gabbro-norite comprises mainly altered olivine, and pyroxene, biotite and opaques as accessory minerals, with serpentine, epidote and chlorite as secondary phases. The gabbro facies is more differentiated and contains mainly pyroxene, plagioclase and partly altered biotite, with chlorite and sericite as secondary minerals. Geochemically, both facies display an alkaline affinity and enrichment patterns characteristic of ocean-island basalt (OIB)-type mantle source that underwent fractional crystallization. Their mineral chemistry and geochemical signatures point to an anorogenic intracontinental rift setting, likely related to late Jurassic-early Cretaceous magmatic event in the Central High Atlas.

Petrochronology with garnet and monazite was performed on refurbished metapelite samples from the Central Kaoko Zone (CKZ), the Western Kaoko Zone (WKZ) and the Orogenic Core Zone (OCZ). P-T path segments of garnet crystallisation were reconstructed by geothermobarometry based on continuous cation exchange and net transfer reactions. The oldest metamorphic monazite populations of 1490 ± 15 Ma and 635 ± 7 Ma occur enclosed in garnet porphyroblasts and signal Meso-Proterozoic and early Pan-African high-grade metamorphic events. According to the sample position next to a 550 Ma granitoid gneiss, a monazite population at 552 ± 4 Ma may be assigned to a local contact metamorphism. In the WKZ and OCZ the further monazite age isochrones range from 546 ± 12 Ma to 532 ± 5 Ma, and in the CKZ from 528 ± 4 Ma to 502 ± 5 Ma. When interpreted in terms of metamorphic P-T paths and the stability field of monazite, the formation of these late Pan-African monazites are pre-, syn-, and postcrystalline to late Pan-African garnet blastesis. P-T conditions for Mg-rich garnet rims increase from E to W within the CKZ from 550 to 650 °C at 9 kbar. Maximal P-T conditions in the OCZ were 705 °C/7.9 kbar. Garnets in the WKZ display retrograde zonation trends with Mg-rich cores crystallising at 700 °C/4–6 kbar. In the westernmost WKZ sample the garnet core crystallised at 780 °C/7.4 kbar and could be of early Pan-African age. Monazite ages and geothermobarometry confirm results from isotope age dating methods.

The Felbertal tungsten mineralisation in the Tauern Window (Eastern Alps) is hosted by the Early Paleozoic Habach Complex belonging to the Lower Schieferhulle. In predominantly mafic meta-volcanic rocks, mostly amphibolites, green amphibole crystallised in assemblages with plagioclase, epidote, chlorite, sphene and quartz. Microstructural features and preferential orientation of the amphiboles define planar-linear structures of finite strain and indicate that their crystallisation is coeval to the main deformation event. Amphibole crystals display core-to-rim zonations with increasing Al-IV, Al-VI, Na and Ti and decreasing Si, covering actinolite over magnesio-hornblende to tschermakite compositions. Amphibole zonations and assemblages are similar to metabasites in the classical Barrovian mineral zones in the Dalradian of Scotland and typical of a prograde metamorphism from the greenschist over epidote-amphibolite to the lower amphibolite facies. Amphibole endmember geothermobarometry defines an early P-T path segment from 400 degrees C/2 kbar to 540 degrees C/6 kbar, and a consecutive later P-T path segment from similar to 500-540 degrees C/6 kbar to maximal P-T conditions of similar to 620-640 degrees C/7-8 kbar. As Carboniferous granitoid intrusions within the Habach Complex underwent penetrative ductile deformation, an Alpine Tertiary age of the lower amphibolite facies metamorphism, as observed in other parts of the Lower Schieferhulle, appears suitable.

The Variscan Slcz(center dot)a ophiolite, located in the NE part of the Bohemian Massif, reveals an ophiolitic sequence with plutonic intrusions predominated by isotropic gabbros. This is a rare example of an ophiolite showing chromitites in its mantle and oxide metagabbros or ferrogabbros in its plutonic sections. Mafic rocks with higher contents of Fe-Ti oxides (8.0-21.8 vol% magnetite and ilmenite) contain also accessory Fe and Cu sulfides. Similarly, this enrichment also occurs in the subvolcanic rocks. Fe-Ti oxide-bearing rocks are distinctly enriched in other trace elements, including REEs, compared to oxide-poor rocks. In plutonic rocks, magnetite and ilmenite occur in various microtextures reflecting sub-solidus breakdown of magnetite-ulvo & uml;spinel solid solutions. Conversely, only ilmenite occurs in subvolcanic rocks, attributed to their lower oxidation conditions compared to plutonic rocks. Magnetite shows a chemical composition, determined by LA-ICP-MS, pointing to a magmatic origin. Ilmenite displays variability in Mn content depending on its location (Slcz(center dot)a Mountain or Kunow gabbro intrusion), likely due to crystallization from variable evolved melts. Mafic rocks rich in Fe-Ti oxides also contain accessory apatite crystals, dated at 313.0 +/- 5.5 Ma using U-Pb method, as well as titanite occurring in intergrowths with primary oxides. The presence of Fe-Ti oxide and Fe-Cu sulfide-rich gabbros is typical for oceanic lithosphere that developed under intermediate to slow-spreading conditions. This is linked to the existence of deformational structures within the Slcz(center dot)a ophiolite, which were utilized by migrating late-stage, Fe-and Ti-rich, evolved, silicate melts squeezed from the surrounding gabbroic rocks. The relatively low concentrations of metals other than Fe, Ti, and V in the oxide mineralizations of ferrogabbros and oxide metagabbros suggests that the environment, where these melts formed, was of low fertility in terms of metal content, which aligns with the overall trace element depletion observed in the Slcz(center dot)a ophiolite. The textural and chemical diversity of Fe-Ti oxides from the plutonic and subvolcanic rocks of the Slcz(center dot)a ophiolite indicates their multi-stage evolution: their formation was associated with the late stage of gabbroic intrusion development, while the presence of secondary phases (e.g. titanite, apatite) is related to metamorphic alteration under seafloor and subsequent regional metamorphism.

The tectonometamorphic evolution of Paleozoic basement inliers of Patagonia remains largely elusive and has been poorly constrained even though it represents a key piece to reconstruct the timescales and tectonic processes during early construction of the continental crust. In this work, new monazite electron probe microanalysis (EPMA) Th–U–Pb data are integrated with a review of structural, microstructural, and thermo-barometric information of medium- to high-grade metasedimentary rocks of northern Patagonia, providing constraints on the timescales of Paleozoic orogenic processes. Early to middle Devonian regional metamorphism records high-temperature/low-pressure conditions linked with a retreating accretionary orogen with widespread forearc to retroarc magmatism. After closure of associated extensional basins during a late Devonian compressional stage, changing geodynamic conditions are documented. During the middle to late Carboniferous, progressive crustal thickening linked with the transpressional Gondwanide Orogen gave rise to medium- to high-pressure/high-temperature Barrovian metamorphism. Crustal thickening, possibly linked with flat-slab subduction, favored an inland migration of metamorphism and deformation. Therefore, the arc domain records Permian Buchan-type metamorphism during post-orogenic collapse, whereas coeval Barrovian-type metamorphism associated with crustal shortening occurs in the retroarc domain. This ubiquitous crustal thickening resulting from the Gondwanide Orogeny ultimately contributed to the stabilization of the relatively thin continental crust of northern Patagonia, which resulted from mainly retreating, early to middle Paleozoic subduction.

Petrochronological studies are essential for understanding the evolution of terrains with multiple phases of deformation. In the context of the northern Ara & ccedil;ua & iacute; Orogen, metapelitic rocks preserve crucial evidence of the metamorphic processes and evolutionary history. In this work, we have studied the Turmalina-Capelinha segment to unravel one more piece of the evolution of the orogen, using a multi-proxy methodology that combines mineral chemistry, geothermobarometric P-T calculations, thermodynamic modelling and Th-U-Pb EPMA monazite dating of (staurolite)-garnet-bearing mica schists. Garnet and staurolite are index minerals formed syn-to post-tectonically with respect to the main schistosity. Garnet porphyroblasts display well-developed compositional zoning of Mg-Fe-Mn-Ca, with increasing almandine and pyrope and decreasing spessartite and grossular contents from cores to rims, indicative of a prograde metamorphic setting. Phase equilibrium modelling and garnet end-members isopleths provide P-T estimates for the metamorphic peak of 540-580 degrees C at 5.2-6.2 kbar (garnet zone) and 570-603 degrees C at 4.9-5.7 kbar (staurolite zone), corresponding to an east-clockwise trajectory within the low-to medium amphibolite facies. In-situ Th-U-Pb monazite ages for these samples range from 468 Ma to 545 Ma. These ages are interpreted as recording a hydrothermal fluid circulation event during the final stages of the evolution of the Ara & ccedil;ua & iacute; Orogen, representing the youngest metamorphic overprint in the metasedimentary rocks, and therefore not directly related to the established P-T conditions.

In the Southern Brasília Orogen (south-eastern Brazil), a nappe system that represents the roots of a magmatic arc records HT-UHT metamorphic conditions in lower to mid-crustal rocks. It is divided into two segments by a major shear zone, of which the northern nappe hosts the most extreme metamorphism and has been targeted for most petrochronological studies. These rocks carry insights into the stages of orogeny, as well as the first direct evidence of the paleo-active margin basement, and time-constraint (1) a metamorphism related to the magmatic arc consolidation on the active margin at 670-640 Ma and (2) an enduring UHT event related to collision and decompression at 630-590 Ma. The southern nappe (Socorro Nappe) hosts felsic and mafic granulites, amphibolites and migmatites with intricate occurrences and complex pressure-temperature-time histories that may preserve distinct age populations in the inner nappe and its outward boundaries (Embu Terrane and São Roque Domain). The mafic lower to mid-crustal rocks of the Socorro Nappe lack detailed comprehensive studies of their P-T-t evolution. We present new preliminary LA-ICPMS U-Pb and Lu-Hf systematics in zircon retrieved from metamafic rocks such as granulites, amphibolites and orthogneisses, and partial results on conventional thermobarometry and thermodynamic modelling. We investigate the significance of a wide timespan from ca. 750 to 570 Ma where granulites tend to preserve older ages in contrast to amphibolites. However, Hf signatures are complex and also show a wide range of ε values from 0 to weakly radiogenic, and strongly radiogenic that are not straightforwardly related to a clear time evolution. Herein we discuss preliminary insights into the zircon petrochronology and P-T-t evolution of metamafic high-grade rocks as a tool to unravel the tectonic evolution of the southernmost segment of the Southern Brasília Orogen in relation to the adjacent São Roque Domain and Embu Terrane, in the context of the Western Gondwana amalgamation.

The Pan-African rare-element pegmatites of the Alto Ligonha Pegmatite District in northern Mozambique contain abundant Li-rich micas and primary Li aluminosilicates, such as spodumene. Given the rising global demand for Li in the manufacture of Li-ion batteries, these pegmatites are viewed as potential hard rock sources of Li. In this study, five pegmatites from the Alto Ligonha region were investigated to gain a better understanding of the fractionation processes of pegmatite melts that lead to Li enrichment and to assess the economic potential of the Li mineralization. Mica, quartz, and spodumene collected from various zones within these pegmatites were analyzed. Contents of Li, Rb, Cs, Ta, and Tl in mica and of Li and Al in quartz reveal a very strong internal fractionation of the pegmatite melt with progressing crystallization. Li2O contents in micas increase from 0.1 to 1.4 wt% in the wall zones, to 0.3-1.7 wt% in the intermediate zones, to 1.5-3.8 wt% in the core zones and up to 5.4 wt% in the core zone pockets. Using known mica/melt Li partition coefficients, the Li contents of the melt at the initial crystallization stage was calculated to be between 315 and 3910 ppm for the Li-rich pegmatites. The Li saturation of about 5000 ppm in respect to spodumene crystallization was exceeded for most pegmatites at the final core-zone crystallization. The theoretical calculations confirm field observations that spodumene occurs in pegmatite core zones only. The analyzed spodumene show low and variable bulk Li2O contents between 1.2 and 3.0 wt%. The low Li contents in spodumene are mainly the result of kaolinization due to tropical weathering. The final deposition of the released Li, however, could not be identified. Inferred resource calculations revealed that the investigated pegmatites contain low Li2O tonnages. However, spodumene as well as Li-rich mica might be mined selectively as a by-product of gemstone and columbite-tantalite mining.

A Scanning Electron Microscope (SEM)-based Automated Mineralogy (SEM-AM) analysis and Cathodoluminescence (CL) were used to study the mineralogy and texture of a vertical 60 cm profile within the Gebel Kamil impactoclastic fallback deposits. The SEM/AM technique was employed to quantify mineralogical and textural criteria such as distribution, grain size, sorting, mineral association, and shape of clastic deposits in two units of the profile. Microscopically, these deposits are composed mainly of unshocked and shocked quartz, along with impactogenic particles such as lithic ejecta, glassy and impact melt fragments, and projectile shrapnel. SEM/ AM effectively identified taenite as the main projectile debris, distinguished various primary mineral phases and related alterations, and microscopically unresolvable inclusions such as tantalite. The impact melt composition was characterized as a Si-rich lechatelierite white melt surrounded by a dark melt. The SEM/AM analysis delineated the composition variance between (Fe-rich) hematite and (Fe-Al-Si-rich) almandine melts. Quantitative textural aspects of the SEM/AM indicate a higher concentration of shocked and other impactogenic particles in the lower unit of the deposits created by the impact plume, whereas the more sorted, finer, more altered upper unit inferred a higher degree of mixing with non-impact related Holocene sediments. The CL results identified shock-induced features, alteration products, and zoning in specific minerals. They also provided insight into the origin of the target rocks, indicating their derivation from a Precambrian complex. The vertical variation of authigenic minerals suggests the presence of a phyllic, post-impact hydrothermal alteration affecting these porous deposits.

Archean granitoids played key roles in the generation and differentiation of the Archean continental crust and provide clues to understand crustal processes in the early Earth. Abundant Mesoarchean granitoids were emplaced in the Nyabessane granite-greenstone terrane (NGB), part of the Ntem Complex of the Northwest Congo Craton. They include charnockites, tonalite-trondhjemite-granodiorite (TTG), granitic and monzogranitic gneisses. Here, we present a geochemical and geochronological (zircon LA-ICP-SF-MS U-Pb) study of these granitoids to determine their petrogenesis and to better constrain the crustal evolution of the Ntem Complex. Field and petrographic observations indicate that most of these granitoids underwent extensive metamorphism and deformations, associated with anatexis. Zircon U-Pb dating results suggest that the charnockite, TTGs and granitic gneisses, and monzogranites have emplacement ages of 2910 +/- 11 Ma, 2870-2865 Ma and 2852 +/- 31 Ma, respectively. The charnockites have low SiO2 (55-58 wt%) and high Al2O3 (16-18 wt%), CaO (7-8 wt%) and MgO (-4.5 wt%) content with Mg# -54, and exhibit magnesian, metaluminous characteristics of the Cordilleran granitoid-type formed in magmatic arc. The 2.87-2.86 Ga TTG gneisses are silica-rich (55-58 wt% SiO2), sodic (3-5 wt% Na2O, Na2O/K2O = 1-3), with HREE-depleted, and display the typical Archean medium -to low pressure TTG geochemical features groups. Their chemical compositions are characteristics of TTG-like melts derived from the partial melting of hydrated low-to high-K metabasic/thickened lower crust at various depths followed by magmatic differentiation during ascent. When compared to the TTG gneisses in the NGB, the-2.87 Ga granitic gneisses are K-rich, and high Gd/Yb, Th/Yb, Th/Nb, Sr/Y and La/Yb ratios but lower MgO, Yb, V, Y, Cr, Ni and Sr contents, matching typical Archean hybrid and potassic granitic rocks. We propose that the granitic gneisses were derived from the intra-crustal melting of a pre-existing felsic crust. The granitic and the TTG gneisses were generated contemporaneously through the same magmatic event at-2.87-2.86 Ga. The-2852 Ma monzogranitic gneisses are ferroan and metaluminous rocks, and show LREE enrichment with strongly fractionated REE patterns and positive Eu anomalies. Geochemical features, together with the presence of-2.9 Ga-old inherited zircon grains are consistent with the remelting of Mesoarchean granitoids. Considering the petrogenetic, regional geological and geochronological data, the Mesoarchean granitoid magmatism of the Ntem Complex was likely generated via complex transitional geodynamic regimes involving subduction and accretion processes.

A protocol for the monazite (LREE,Y,Th,U,Si,Ca)PO4 in situ Th-U-Pb dating by electron probe microanalyser (EPMA) involves a suitable reference monazite. Ages of several potential reference monazites were determined by TIMS-U-Pb isotope analysis. The EPMA protocol is based on calibration with REE-orthophosphates and a homogeneous Th-rich reference monazite at beam conditions of 20 kV, 50 nA, and 5 µm for best possible matrix matches and avoidance of dead time bias. EPMA measurement of samples and repeated analysis of the reference monazite are performed at beam conditions of 20 kV, 100 nA, and 5 µm. Analysis of Pb and U on a PETL crystal requires YLg-on-PbMa and ThMz-on-UMb interference corrections. Offline re-calibration of the Th calibration on the Th-rich reference monazite, to match its nominal age, is an essential part of the protocol. EPMA-Th-U-Pb data are checked in ThO2*-PbO coordinates for matching isochrones along regressions forced through zero. Error calculations of monazite age populations are performed by weighted average routines. Depending on the number of analyses and spread in ThO2*-PbO coordinates, minimum errors <10 Ma are possible and realistic for Paleozoic monazite ages. A test of the protocol was performed on two garnet metapelite samples from the Paleozoic metamorphic Zone of Erbendorf-Vohenstrauß (NE-Bavaria, western Bohemian Massif).

Granites are widespread in many Precambrian orogenic belts worldwide; therefore, they can provide insights into orogenic processes and associated magmatism. Zircon U-Pb age, monazite Th-U-total Pb age and wholerock geochemical data for a granite pluton from the Gari-Gombo area in the Adamawa-Yade domain of the Central African Fold Belt (CAFB) in East Cameroon are presented. The granite is composed dominantly of perthitic K-feldspars, quartz, plagioclase and minor biotite with accessory monazite, apatite and zircon. LA-ICP-MS zircon U-Pb dating yielded an age at ca 631-620 Ma, which is interpreted as age of emplacement that coincides with the onset of D2 Pan-African deformation. Monazite grains in Gari-Gombo granite follow strictly the huttonite substitution trend in Th + U vs Si coordinates. Monazites give consistent Neoproterozoic ages of 630 +/- 4 Ma and 602 +/- 4 Ma, indicating that growth history and crystallization age of monazites also correlate well with the Pan-African plutonism and granulite facies metamorphism (ca 614-600 Ma) in the Gari-Gombo area. The Gari-Gombo pluton samples show high-K calc-alkaline magnesian, slightly peraluminous signature, high SiO2 (70.16-78.80 wt%), K2O (4.39-5.38 wt%), and Rb (165-248 ppm), and low P2O5 <= 0.01 wt% and Sr (146-222 ppm) contents. They have highly-fractionated REE pattern ((La/Yb)N = 6.17-148.18), moderately Eu negative anomalies (Eu/Eu* = 0.53-0.93) and the obviously Nb and Ti negative anomalies. These geochemical features suggest that the Gari-Gombo pluton is a highly fractionated I-type granite generated by partial melting of older meta-igneous materials at middle to lower crustal levels. The 2.9 and 0.95 Ga inherited zircon grains identified within the studied granites further confirm the existence of ancient crust in this region.

The Felbertal tungsten deposit is the only economic scheelite mine in Europe, yet its genesis is not fully understood. It has been argued recently that the formation of the deposit is most likely related to granitic intrusions of Variscan age, contrasting a previously suggested syn-depositional stratabound origin of Early Cambrian age. Solving this controversy remains challenging due to the polymetamorphic evolution of the deposit, which experienced both Variscan and Alpine metamorphism. In this contribution we present a comprehensive new data set of scheelite major, minor, and trace element concentrations from multiple scheelite generations of the Felbertal deposit along with microstructural observations. Our results show that Mo, Mo/Mn, REE, Y/Ho, Nb, and Nb/Ta in scheelite are variable within the different scheelite generations and are predominantly controlled by the host-rock lithologies on the local scale, whereas in general the data show a strong response to the shift of P, T, and pH upon changing magmatic-hydrothermal to metamorphic conditions. For the first time, we identify remnants of primary scheelite in the Western Ore Zone. The presented data support a magmatic-hydrothermal origin of the first scheelite mineralization during the Variscan orogeny with primary scheelite being characterized by wing-shaped REE patterns with a negative Eu-anomaly, high trace element concentrations, non-chondritic Y/Ho, and high Nb/Ta. Primary scheelite underwent metamorphic/hydrothermal alteration (recrystallization and dissolution-reprecipitation processes) during the Variscan and Alpine orogeny. This case study highlights that indicative mineralization-controlling geochemical ratios like Sr/Mn cannot be applied for polymetamorphic tungsten deposits like Felbertal.

We study three ultrabasic-alkaline carbonatite complexes (UACCs: Afrikanda, Vuorijarvi, Kovdor) from the Kola Alkaline Province to focus on the comparison of REE contents from pyroxenites and carbonatites and the fate of perovskite. Pyroxenites and carbonatites have large REE variations and similar contents in all three complexes. Afrikanda and Vuorijarvi pyroxenites and carbonatites have higher REE contents compared to all Kovdor rocks. Despite their comparable LREE contents, pyroxenites and carbonatites have different REE-carrier minerals. In most studied pyroxenites, perovskite is the main REE-bearing mineral and its abundance controls the LREE enrichment of the whole rock. When perovskite is absent or in low abundance, apatite is the main REE carrier. Instead, in carbonatites and phoscorites, apatite and calcite control REE contents. REE-carbonates - found in several carbonatite samples - do not play a substantial role in the overall REE budget because of their very low abundance and tiny grain sizes. We found large LREE variations at very low local scales (< 1 mm) in several thin sections. These large variations are related to carbonatite infiltration and associated antiskarn reactions. Perovskite near calcite is replaced by titanite that has much lower LREE contents. Most LREE released from the breakdown of perovskite were probably dissolved in the carbonatite melt because apatite and calcite that crystallized from this melt are highly enriched in LREE. Newly formed apatites and calcites show large LREE variations that probably are controlled by local factors (e.g. variations of Si, Ca, Mg activities). Y/Ho ratios are strongly fractionated in most minerals and often show large variations at local scales (mm) in these antiskarn reactions. The potential of REE remobilization from such perovskite replacement reactions is very high as perovskite contributes about 70% to the REE budget for these three UACCs. Therefore, more attention should be given to perovskite replacement reactions and its role for LREE enrichment of carbonatite melts.

The geologic evolution of the Gondwanide orogen recorded during the late Palaeozoic along the Panthalassan border of Gondwana is related to an active continental margin, though it is still debatable whether it was built by collision or accretion. To disentangle its orogenic processes and provide constraints on the orogen type, we characterize the physicochemical conditions of metamorphism and associated deformation of the Mina Gonzalito Metamorphic Complex from northern Patagonia (41 degrees 28 ' 30 '' S-65 degrees 40 ' 30 '' W). New field mapping and comprehensive petrochronologic analysis constrain the evolution of a thick-skinned fold and thrust belt in a retroarc setting, which is spatially and temporally related to the geometry and kinematics of the right-lateral reverse El Jaguelito ductile shear zone. Metamorphic evolution resulted in a clockwise P-T-t-D path reflecting three stages of continuously changing P-T conditions under high-pressure (8.0-9.9 kbar) amphibolite facies (540-680 degrees C) during a single-phase progressive ductile deformation event. Monazite ages ranging from 303 +/- 5 to 252 +/- 6 Ma account for the single-phase regional tectono-metamorphic event spanning similar to 50 My. Our results, integrated with regional data, led to interpreting the late Palaeozoic Gondwanide orogen developed along the Panthalassan margin of Gondwana as accretionary in advancing-mode. [GRAPHICS] .

The Sierra de Mamil Choique calc-alkaline granite batholith, covering an area of 320 km(2), serves as the key reference for Late Paleozoic magmatism in central-west Patagonia. It comprises I-type weakly to mildly peraluminous tonalites to granites (59.6-75.7%SiO2) displaying various deformational features. This paper presents a micro- and mesostructural study alongside temperature-pressure (T-P) constraints coupled with U-Pb zircon crystallization ages, as well as Ar-Ar and K-Ar mica ages, and mineral and whole-rock geochemistry. The older units (288 +/- 1 Ma Cerro Moj & oacute;n Monzogranite and 281 +/- 2 Ma Huenchuquil Granodiorite), exhibit syn-kinematic banding and strong NW-SE foliation showing a transition from magmatic-sub magmatic to high-T subsolidus deformational features, such as parallel alignment of magmatic minerals, sub magmatic fractures, melt pockets, and chessboard subgrains in quartz. Quartz recrystallization by grain boundary migration is also observed. These microstructures developed concurrently with the regional D3 event that affected the Devonian metamorphic host. Their crystallization started at 8 Kbar and similar to 790 degrees C within a thickened crust (La-N/Yb-N = 13-15, average). In contrast, the younger units (278 +/- 2 Ma; Nahuelfil and Antinao Monzogranites) exhibit mainly magmatic deformation and display a NE-SW parallel alignment of mostly subhedral K-feldspar. A D4 deformation younger than 278 Ma, with a sigma 1 NW-SE (in plain view- horizontal) would have controlled the emplacement of Nahuelfil and Antinao Monzogranites. Younger zircon ages (ca 265 Ma) in the 278 Ma monzogranites would result from resetting due to the magmatic-hydrothermal alteration associated with the later magmatic pulse of leucogranites and pegmatites of the 267 +/- 8 Ma (Rb-Sr WR isochron) La Pintada Leucogranites. These leucogranites were emplaced in an already thinner crust (La-N/Yb-N = 2.6 average). The latest magmatic activity is represented by two groups of pegmatitic bodies one from 265 +/- 6 to 257 +/- 3 Ma and a younger one of ca. 252-251 Ma (Ar-Ar and K-Ar muscovite cooling ages). All units share a common mafic source, but the younger units crystallized from melts at lower pressure and temperature (748-725 degrees C). The magmatism, involving crustal recycling, occurred at an active margin during a stage of thickened crust from 290 to 280 Ma, followed by gradual thinning after 280 Ma. This change in crustal thickness fits models proposing a continuous Permian subduction with a variable dip angle of the subducted slab along the southwestern margin of Gondwana.

Greywackes make up a substantial part of the Cadomian basement of Saxo-Thuringia. Here, their classification as greywackes and the timing of metamorphic overprint are re-evaluated using a multi-method approach. Immature monotonous greywacke sequences from the Lausitz (Lausitz Block) and Leipzig groups (North Saxon Anticline), as well as from the eastern Thuringian Basin and parts of the Weesenstein Group (Elbe Zone) probably belong to a coherent unit, based on microscopic investigations supported by SEM Automated Mineralogy analyses and point counting data. However, due to the low matrix content (< 15