We summarize evidence for Quaternary and active faulting collected in the field during three

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Kinematics of faults in the Northern Aegean show three extensional tectonic regimes the tensional directions of which trend (1) WNW‐ESE, (2) NE‐SW and (3) N‐S. These were active during the Upper Miocene, Pliocene‐Lower Pleistocene and Mid Pleistocene‐Present day, respectively. The main characteristics of the stress patterns (1) and (2) on the overall Aegean is tentatively explained by variations of the horizontal lithospheric stress value σzz due to the slab push and of the vertical lithospheric stress value σzz due to mass heterogeneities. During the Mid Pleistocene‐Present, due to the slab push, tectonics were compressional along the arc boundary: σzz was σ1. In the Aegean basins, tectonics were extensional, c2Z was σ1 as a consequence of the thickness of the continental crust and, possibly of an updoming asthenosphere; thus σzz became σ2, allowing tension σ3 to be orthogonal to the compression along the arc, i.e. to be roughly parallel to the arc trend. During the Pliocene‐Lower Pleistocene, the extensional regime was distinctly different. The tensional directions were roughly radial to the arc. It is suggested that σzz was weakly compressional, or eventually tensional, due a seaward migration of the slab so that σzz became σ3. In the Northern Aegean, the stress pattern has been also controlled by the westward push of the Anatolian landmass. During the Mid Pleistocene‐Present day, this was typically extensional (al was vertical) and the right lateral strike‐slip motion on the North Anatolian Fault transformed into a N‐S‐stretching, E‐W‐shortening of the Northern Aegean. Dextral strike‐slip motions along the North Aegean Trough fault zone were possible on NE‐SW‐striking faults. During the Pliocene‐Lower Pleistocene, normal fault components were higher; however, because the angle between the NE‐SW trend of the tensional axis and the strike of the fault zone was acute, dextral strike‐slip components were possible on all the faults striking NE‐SW to E‐W. A clockwise 15o rotation of Limnos with respect to Samothraki, Thraki and Thassos, suggested by structural data, was probably associated with these dextral motions. The WNW‐ESE trending tension during the Upper Miocene indicates that the dextral North Anatolian Fault had not yet merged into the North Aegean Trough fault zone at that time. We propose that the formation of Aegean basins during the Cenozoic was related to the activity of two major Hellenic arcs. The ‘Pelagonian‐Pindic Arc’ resulted in the formation of the subsident Aegean basins of Middle Eocene‐Lower Miocene age and of the older Northern Aegean orogenic volcanism. The ‘Aegean Arc’ resulted in the formation of the subsident Aegean basins of Middle Miocene to Present day age and of the Southern Aegean orogenic volcanism. Were these arcs associated with a unique subduction zone or with two such zones ? In the first case, the slab is no more than 16 Myr old, in the second it may be as old as 45–50 Myr. The answer depends on the accuracy of the seismic tomography profiles.

The results cover a statistical analysis of the correlations between aquatic macrophyte communities and chemical parameters (N-NH4, N-NO3, P-PO4, COD, Temperature, dissolved 02, C1) in unpolluted hard waters (upper Rhine rift valley).This study was based on a table of phytosociological relev6s for six plant communities, named A, B, C, CD, D and E. The ecological determinism of the communities were defined from: The study of the seven foregoing physico-chemical parameters for 29 groundwater streams on periodical samples of water. The study of the change with time in the aquatic vegetation after change of the trophic status, confirmed by analysis. The comparative study of the vegetation of the streams and parts of the streams with different trophic statuses but fed by the same groundwater table of the Wurmian Rhine gravels.Analysis of the main components showed the good correlation between the macrophyte communities and the trophy (N-NH4, P-PO4). These six communities were classified according to the trophic scale. Discriminant analysis was used to compare the classification of the phytosociological sequence with that based on the statistical analysis. The authors give a very precise bioindication scale (based on the macrophyte community) for the eutrophication degree in unpolluted hard waters.

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Field studies in the Andes of southern Peru show that in the High Andes and Pacific Lowlands, Quaternary and Recent faults are normal. This extensional tectonics postdates compressional deformations of Pliocene‐early Quaternary age. In the sub‐Andes the observed deformations are compressional; they affect early Quaternary deposits. Some of the faults separate Quaternary deposits from the bedrock and thus are clearly of tectonic origin and not landslide effects. Striations on the fault planes indicate N–S trending extension in the High Andes and Pacific Lowlands. The total amount of crustal stretching is small, probably of the order of 1% during the last 1–2 m.y. In the sub‐Andes, folds and faults affecting Neogene and early Quaternary deposits result from N–S shortening. Nevertheless, it is supposed that this N‐S shortening is of early quaternary age. The present‐day compression probably strikes E‐W, judging from focal mechanisms in the sub‐Andes of central Peru, southern Bolivia, and northwest Argentina. Data from structural analysis of faults and from earthquake focal mechanisms allow us to surmise the state of stress in the Andes of southern Peru. The High Andes and Pacific Lowlands, subjected to N‐S trending extension, are bounded by two zones of E‐W trending compression: the sub‐Andes to the east, and the contact between the convergent Nazca and South America plates to the west. In our model the maximum horizontal compressive stress trajectory σ Hmax is roughly parallel with the E‐W convergence between the two plates; σ Hmax corresponds to σ 1, in the sub‐Andes and to σ 2 in the High Andes. The latter situation is caused by the elevated mass of the High Andes, where σ zz (the vertical stress) is inferred to be σ 1. Thus the third principal stress axis, being orthogonal to the other two axes, it is oriented N‐S, allowing extension to occur in that direction. On the other hand, in the sub‐Andes σ zz is σ 3, and horizontal E‐W shortening occurs. The state of stress in the Andean continental crust above the 30° dipping slab appears to be different from that in the Andes of Central Peru situated above the flat subducting segment. In this region, compressional deformantion affect a wider part of the Cordillera.