In the WNW‐ESE Donbas fold belt (DF), inversion of 3500 microtectonic data collected at 135 sites, in Proterozoic, Devonian, Carboniferous, and Cretaceous competent rocks allowed reconstruction of 123 local stress states. Accordingly, four successive paleostress fields reveal the tectonic evolution of the DF. At the numerous sites that have been affected by polyphase tectonics, the chronology between local paleostress states (also paleostress fields) was established using classical criteria (crosscutting striae, pre‐ or post‐folding stress states, stratigraphic control). The oldest event is an extensional stress field with NNE‐SSW σ3. It corresponds to the rifting phases that generated the basin in Devonian times and its early Visean reactivation. Later, the DF was affected by a transtension, with NW‐SE σ3 characterizing Early Permian tectonism, including the development of the “Main Anticline” of the DF and the pronounced uplift of its southern margin and Ukrainian Shield. Two paleostress fields characterize the Cretaceous/Paleocene inversion of the DF, which was accompanied by folding and thrusting. Both are compressional in type but differ by the trend of σ1, which was first NW‐SE and subsequently N‐S. The discrete paleostress history of the DF allows a revised interpretation of its tectonic evolution with significant implications for understanding the geodynamic evolution of the southern margin of the East European Craton.

Available geochronological (U-Pb andAr/Ar) and geological data indicate that the Corner Brook Lake block of the Humber zone in the western Newfoundland Appalachians has unique characteristics. Grenvillian ages (ca. 1.0 Ga), which are typical for the Laurentian Appalachian margin, are absent in the crystalline basement to the Corner Brook Lake block. This makes it unlikely that the block is underlain by true parautochthonous Humber margin basement. However, the lithological makeup of its late Neoproterozoic-Early Cambrian sedimentary cover and detrital zircon populations indicate a Laurentiantype provenance. In addition, there is no geochronological or other geological evidence for a Middle Ordovician tectono-thermal event in the Corner Brook Lake block, suggesting that it escaped the penetrative tectono-thermal effects of the Taconic collision present elsewhere in the Laurentian realm. Instead, the block underwent strong regional deformation and associated peak metamorphism during the Silurian Salinic orogeny. Combined evidence, including the absence of Grenvillian ages, the presence of late Neoproterozoic ca. 600 Ma granitoid plutons, the regionally distinct early Paleozoic tectonic history of the Corner Brook Lake block, and its faultbounded nature, implies that the block represents an allochthonous terrane. Available data indicate that signifi cant orogen-parallel movement of the block (possibly 400 km or more) could have taken place during the Appalachian orogeny. The possibility of largescale strike-slip tectonics, in addition to the well-documented convergent motions, has signifi cant implications for the tectonic interpretation of the early Paleozoic evolution of the Newfoundland Appalachians.

The Dashwoods microcontinent is an important tectonic segment in the peri-Laurentian setting of the Newfoundland Appalachians. In order to better understand the tectonic history of Dashwoods during the Ordovician Taconic orogeny, we have undertaken field mapping, microscopic studies, and U-Pb and 40 Ar/ 39 Ar geochronological studies along the northern (Little Grand Lake Fault; LGLF) and western (Baie Verte Brompton Line -Cabot Fault Zone; BCZ) boundaries.Oblique-dextral ductile deformation in the BCZ occurred from late Middle Ordovician into the Early Silurian, based on the presence of a late syn-tectonic pegmatite dike (455 ؎ 12 Ma) and a foliated granodiorite sheet (445.8 ؎ 0.6 Ma). Deformation is coeval with oblique-sinistral accretion along the eastern margin of Dashwoods, which means that Dashwoods and its Notre Dame Arc had a southward translation with respect to the Laurentian margin and the then-present Iapetus Ocean during the Late Ordovician. Dextral movement along the BCZ continued after the collision of Dashwoods with the Laurentian margin. Deformation along the Little Grand Lake Fault is bracketed between 463 ؎ 5 Ma and 440 ؎ Ma. These ages combined with other geological arguments indicate that motion probably took place during the Late Ordovician to earliest Silurian contemporaneous with the southward translation of Dashwoods. A possible explanation is that the Snooks Arm arc moved independently from and faster southwards than the Notre Dame Arc with its Dashwoods infrastructure, thereby underthrusting the Dashwoods along the Little Grand Lake Fault.Our new U-Pb geochronological data, including a muscovite granite (463 ؎ 5 Ma), a schistose muscovite granite (459 ؉17 / -21 Ma), and a tectonized tonalite (458 ؎ 20 Ma), add to the geochronological database of the voluminous second phase of the Notre Dame Arc. Additionally, in all-but-one of our U-Pb samples, inherited grains of Mesoproterozoic (circa 1.0 Ga) age have been obtained. Their regional presence fortifies the possible relationship of the Dashwoods microcontinent with the Long Range Inlier in western Newfoundland. Furthermore, it introduces a potential link with the Blair River Inlier in Cape Breton Island.

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