Abstract Calcite petrofabrics are sensitive to weak strains, possibly being the most sensitive classical petrofabric indicator. Thus, calcareous sediments may reveal stress trajectories in neotectonic environments. Calcite aligns by crystal-plastic deformation and pressure solution produce corresponding alignments in accessory clay minerals and magnetite (possibly fossil-bacterial). Their alignments are rapidly and precisely detected by anisotropy of low field magnetic susceptibility (AMS) with net magnetic fabrics, which blend diamagnetic contributions from matrix calcite (diamagnetic bulk susceptibility κ ∼ −14 μSI), accessory clay minerals (κ = 100 to 500 μSI) and sometimes trace magnetite (κ > 2 SI). Their relative abundances and different anisotropies must be considered in interpreting AMS orientations, nevertheless our study reveals orientation distributions of AMS axes in sub-areas and regions that are sensibly interpreted as palaeostress trajectories in Neogene and Quaternary strata. The AMS axes may be correlated with the orientation of faults, plate-motion vectors and seismic solutions. Large samples (1090 specimens from 419 sites) are treated by different statistical approaches (‘standardization’) to emphasize or suppress the contribution of subfabrics with anomalous mean susceptibility. A sub-sample of 254 specimens from 219 sites, from different sub-areas was investigated by anisotropy of anhysteretic remanence (AARM), which isolates the orientation distributions of magnetite. Magnetic fabrics are mostly of the L-S kind with the magnetic lineations compatible with gravitational stretching of the sedimentary cover away from the Troodos massif and orthogonal to the principal faults and graben. The L-direction ( k max ) shows a smooth variation in orientation, through the sub-areas, directed radially from the Troodos massif and the S-components of the magnetic fabrics are inclined gently to the bedding, compatible with vergence toward the Cyprean Arc to the S and SW of Cyprus.

Abstract Glaciers cover only about 5 percent of Alaska today, but they spread over as much as half of the state during the most widespread advances of the late Cenozoic (Fig. 1). Both modern and ancient glaciers have been most extensive in southern Alaska, where they were close to moisture sources in the North Pacific Ocean and the Gulf of Alaska (Fig. 2). Glaciers were smaller farther to the north because the nearest water bodies were icecovered for much of the year and broad continental platforms were emergent during times of glacioeustatic sea-level lowering. The repeated glaciations of late Cenozoic time had great impact even on nonglaciated parts of Alaska, where they caused formation of proglacial lakes, construction of outwash terraces, loess deposition, and isostatic depression of coastal lowlands. Because the Alaskan glacial record interrelates with so many other physical processes and climate-related features, it provides the fundamental stratigraphic framework for the late Cenozoic history of much of the state. The positions of readily accessible glaciers along the southeastern Alaskan coast were recorded during 18 th century explorations of La Perouse, Cook, Vancouver, and others, and detailed studies of those glaciers and their fluctuations began near the close of the 19th century (Reid, 1896; Gilbert, 1904; Tarr and Martin, 1914). Compilations of the statewide glacial record have been published by Capps (1932), Pewe and others (1953), Karlstrom and others (1964), Coulter and others (1965), and Péwé (1975). Ancient as well as modern glaciers in Alaska were primarily alpine in character. Glaciers

Glaciers originating in the central Brooks Range extended south into the lower Alatna Valley during three major episodes of Illinoian and Wisconsin glaciation. During the oldest glaciation, coalescing glaciers formed a piedmont ice sheet that extended 60 miles south of the range and covered most of the Koyukuk Lowlands. The later Kobuk Glaciation, subdivided into two stades, was marked by a smaller lobe that terminated in the Koyukuk Lowlands, receded, then readvanced to a frontal position within the Alatna Valley 25 miles closer to the Brooks Range. Drift of the Itkillik Glaciation, which marks the final period of ice advance into the lower Alatna, is subdivided into four moraine belts. Siruk Creek moraines, the oldest and most extensive Itkillik deposits, form an arcuate belt that extends 30 miles south of the range front. The later Chebanika moraine marks a brief readvance or stillstand of glacier ice farther upvalley. Ice then stagnated in the Helpmejack Lakes area, and massive bodies of ice-contact stratified drift were deposited in a broad belt 8 to 15 miles south of the Brooks Range. Moraines at the range front represent the last major event of the Itkillik Glaciation. Subdivisions and correlations of the glacial sequence are based on extent and position of the drift sheets, inferred glacier regimens, postglacial modification of glacial deposits, radiometric dates, and ice limits within the upper Alatna Valley. The four episodes of Itkillik glaciation within the Alatna drainage system appear to be equivalent to four Itkillik stades in the Anaktuvuk Valley, and radiocarbon dates from both areas indicate a late Wisconsin age for Itkillik deposits. The preceding ice advance, correlated with the Kobuk Glaciation farther west, may represent the early Wisconsin. The oldest glaciation is correlated with an ice advance of Illinoian age that filled the Kobuk Valley and extended west into Kotzebue Sound.