The northern Rhine area covers an area of more than 40,000 km 2 and is one of the most important areas of earthquake recurrence in Europe north of the Alps. The Lower Rhine Embayment, a part of the northern Rhine area that extends over parts of western Germany, eastern Belgium, and the southern Netherlands, displays basin-like subsidence and, along with the Roer valley graben, has been the source of most of the historical and recent earthquake activity, particularly along the western border faults. Other important earthquake-prone areas include the Stavelot-Venn Massif and the Neuwied Basin, the latter of which is an area of periodically intensive micro-seismicity. Seismic instrumentation in the area has accumulated steadily since the early 1950s and presently consists of ∼50 stations. Although the strongest instrumentally recorded earthquake in the region occurred in 1992 near Roermond, with a local magnitude of 6.0, studies of historical earthquakes, such as Vervier (1692) and Düren (1756), estimate macroseismic magnitudes of 6.8 and 6.4, respectively. Paleoseismic studies indicate that even stronger, surface-rupturing earthquakes have occurred during the Holocene. The recent M L 4.9 earthquake in Alsdorf in 2002 caused some structural damage and was preceded by several small earthquakes and was followed by several aftershocks. Seismic hazard evaluation is hampered by the sparse earthquake record. A hybridized instrumental and historical earthquake catalog compiled from events over the past 300 yr combined with seismotectonic aspects indicates a maximum magnitude of 7.0. A site-intensity map based on macroseismic intensities from the hybridized catalog identifies concentrations of recent activities in the western part of the Lower Rhine Embayment, east of the city of Aachen.

Abstract Size distribution and evolution of framboidal and euhedral microscopic crystals of pyrite (micropyrites, MPy) have been used for the last thirty years to deduce palaeo-redox conditions. The analysis of the MPy distributions can give valuable information about these palaeo-redox conditions. However, other information can also be retrieved from this type of analysis. In this work, we propose that the formation of new populations of MPy is a proxy of the transition from the anchizone to the epizone. High-resolution X-ray tomography (micro-CT) was used to determine the size distributions of MPy hosted in pelitic rocks subjected to different grades of low temperature metamorphism. These data were filtered and statistically analysed, which allowed us to find a statistical representative size distribution of the MPy present in the samples. The metamorphic grade was determined using the Kübler Index in combination with petrological and scanning electron microscopy (SEM) examination. The results show a relationship between metamorphic grade and MPy size distributions, and that new populations of MPy formed due to the effects of metamorphism. This new methodology for MPy size distribution has different potential applications in some fields of Earth sciences, such as palaeoenvironment reconstruction, ore mining or metamorphic petrology.

Abstract The Ordovician outcrops of central Europe belong to various areas with, in general, a very complex tectonic evolution. In this chapter, we review the localities that were attributed to peri-Gondwanan terranes. We do not therefore include a detailed description of areas attributed to the Baltica palaeocontinent (Denmark, southern Sweden, Baltic States, northeastern Poland). Whereas the northwestern part of Central Europe belonged, during the Ordovician, to the eastern part of the microcontinent of Avalonia (Belgium, western and northern Germany, possibly northwestern Poland), the outcrop areas of the Rhenohercynian, Saxothuringian and Moldanubian zones have mostly been assigned to Gondwana-derived terranes (such as, in palaeogeogra-phical terms, Armorica or the Armorican Terrane Assemblage (ATA) and Perunica) or to sedimentary basins in the vicinity of the Gondwanan supercontinent. Our review includes the Avalo-nian sequences of Belgium in the northwestern part of the investigated area of Central Europe, continues into western, northern and eastern Germany and extends into northwestern and southern Poland. The review of the Ordovician of the Saxothuringian and the Moldanubian zones includes the outcrop areas of southeastern Germany, the Czech Republic and southwestern Poland. The Ordovician from the pre-Variscan parts of the Alpine mountain chains of Switzerland, Austria and northern Italy are also briefly discussed. In terms of stratigraphy, the British Ordovician series and stages were generally used as a standard in most parts of western and central Europe. However, in the last two decades, significant progress has been made in Ordovician series and stage boundary definitions on a global scale. A tripartite division of

Abstract The Ordovician successions of France and neighbouring areas of Belgium and Germany are reviewed and correlated based on international chronostratigraphic and regional biostratigraphic charts. The same three megasequences related to the rift, drift and docking of Avalonia with Baltica can be tracked in Belgium and neighbouring areas (Brabant Massif and Ardenne inliers), western (Rhenish Massif) and northeastern Germany (Rügen). The remaining investigated areas were part of Gondwana in the Ordovician. The Armorican Massif shares with the Iberian Peninsula a Furongian–Early Ordovician gap (Toledanian or Norman gap), and a continuous Mid–Late Ordovician shelf sedimentation. The Occitan Domain (Montagne Noire and Mouthoumet massifs), eastern Pyrenees and northwestern Corsica share with southwestern Sardinia continuous shelf sedimentation in the Early Ordovician, and a Mid Ordovician ‘Sardic gap’. In the Ordovician, the Maures Massif probably belonged to the same Sardo-Occitan domain. The Vosges and Schwarzwald massifs display comparable, poorly preserved Ordovician successions, suggesting affinities with the Teplá-Barrandian and/or Moldanubian zones of Central Europe.

Abstract Sequences of Tremadocian and earliest Arenigian graptolite faunas in North America, Scandinavia, and Taimyr, U.S.S.R., are similar enough to suggest that these regions were coprovincial during that time interval. The most noteworthy difference involves the earliest Tremadocian faunas represented by the Staurograptus fauna in North America (and Australia) and the Dictyonema flabelliforme fauna in Britain, Belgium, North Africa, Scandinavia, Estonia, and Taimyr. The two distributional patterns are known to overlap only in eastern North America. During middle Arenigian to Llanvirnian time, two faunal provinces became differentiated–a European Province including Britain, western Europe, North Africa, and Scandinavia, and a Pacific Province including North America and Taimyr. Arenigian faunas of the European Province are characterized by diversification of multiramose dichograptid genera, including the endemic Ho/ograptus, Temnograptus, and Trochograptus. Expatriate genera and species from the Pacific Province are known from the more westerly localities of the European Province, and expatriate forms from the European Province are present in eastern North America. Pacific middle Arenigian faunas are characterized by pendent Didymograpfus, Goniograptus, and Sigmagraptus, but the late Arenigian genera Cardiograptus, Oncograptus, and Skiagraptus that are so conspicuous in western North America (and Australia) are unknown in the Appalachian geosyncline. During Llanvirnian time, European Province faunas comprised large pendent species of Didymograptus and cosmopolitan biserial genera. In Scandinavia, expatriate elements from the Pacific Province may be present in Holmograptus, Abrograptus, Pterograpius, and terminal species of Isograptus and Tetragraptus. Pacific Province faunas are characterized by sinograptids (especially in western North America), Loganograptus, Pseudobryograptvs, Paraglossograpfus, and terminal