Last interglacial (MIS 5e) sea-level proxies in southeastern South America

Coastal southeast South America is one of the classic locations where there are robust, spatially extensive records of past high sea level. Sea-level proxies interpreted as last interglacial (Marine Isotope Stage 5e, MIS 5e) exist along the length of the Uruguayan and Argentinian coast with exceptional preservation especially in Patagonia. Many coastal deposits are correlated to MIS 5e solely because they form the next-highest terrace level above the Holocene highstand; however, dating control exists for some landforms from amino acid racemization, U∕Th (on molluscs), electron spin resonance (ESR), optically stimulated luminescence (OSL), infrared stimulated luminescence (IRSL), and radiocarbon dating (which provides minimum ages). As part of the World Atlas of Last Interglacial Shorelines (WALIS) database, we have compiled a total of 60 MIS 5 proxies attributed, with various degrees of precision, to MIS 5e. Of these, 48 are sea-level indicators, 11 are marine-limiting indicators (sea level above the elevation of the indicator), and 1 is terrestrial limiting (sea level below the elevation of the indicator). Limitations on the precision and accuracy of chronological controls and elevation measurements mean that most of these indicators are considered to be low quality. The database is available at https://doi.org/10.5281/zenodo.3991596 (Gowan et al., 2020).

Experimental Study and Numerical Analysis on the Vibration Characteristics of a Terraced Slope along an Embankment Section of a High-Speed Railway

The characteristics of the vibrations induced by the passage of a high-speed train do not only depend on the train speed, axle load, and track irregularity but also depend on the properties of the foundation soil and the surrounding topography. Estimating the vibration characteristics in different terrains is therefore essential. This study investigates the characteristics of propagation and attenuation of the vibrations induced by high-speed trains in loess-terraced slopes. The influence of the soil mechanical properties on the propagation of vibrations is analyzed through a numerical simulation. Field experiments are conducted to measure the vibration induced by a high-speed train at a loess-terraced slope site in Qin’an, Gansu, China. The measured acceleration time history is analyzed in the time domain and frequency domain. The results show that, at the edge of each terrace level, the vibration in the Y direction is the strongest, followed by those in the X and Z directions. The peak ground acceleration values are amplified in all three directions at the fourth terrace level. A model describing the vehicle-roadbed-foundation-terraced slope system is established to study the influence of the elastic modulus of the soil on the vibration characteristics. A change in the elastic modulus of the foundation soil is found to have an evident influence on the horizontal and vertical vibrations in each terrace level. However, a change in the elastic modulus of the soil in a terrace only affects the vibration in that terrace and in the adjacent ones, whereas it has no effect on the vibrations in terraces located farther away. This study can provide some reference values for slope reinforcement along railways.

Last interglacial (MIS 5e) sea-level proxies in southeastern South America

Coastal southeast South America is one of the classic locations where there are robust, spatially extensive records of past high sea level. Sea-level proxies interpreted as being Last Interglacial (Marine Isotope Stage – MIS 5e) exist along the length of the Uruguayan and Argentinian coast, with exceptional preservation especially in Patagonia. Many coastal deposits are correlated to MIS 5e solely because they form the next highest terrace level above the Holocene highstand; however, dating control exists for some landforms from amino acid racemization, U/Th (on molluscs), electron spin resonance (ESR), and optically stimulated luminescence (OSL) dating. As part of the World Atlas of Last Interglacial Shorelines (WALIS) database, we have documented a total of 60 MIS 5 proxies attributed with various degrees of precision to MIS 5e. Among these, 48 are sea-level indicators, and 11 are marine limiting indicators (sea level above the elevation of the indicator), and 1 is terrestrial limiting (sea level below the elevation of the indicator). Limitations on the precision and accuracy of chronological controls and elevation measurements means that most of these indicators are considered to be low quality. The database is available at https://doi.org/10.5281/zenodo.3991597 (Gowan et al., 2020).

Geogenesis and pedogenesis of well drained brown soils on the youngest Late Weichselian Meuse terrace in North Limburg, Netherlands.

The Meuse terraces of Late Weichselian and Holocene age can be subdivided into 4 levels. The youngest Late Weichselian terrace occurs partly along and close to the present-day Meuse. On recent soil maps the well drained brown soils, occupying the highest positions of this terrace level, have been indicated as Plaggepts. This implies the presence of a plaggen epipedon of more than 50 cm thick. Three characteristic soil profiles were studied macromorphologically and micromorphologically and samples were analysed for particle size distribution and selected chemical properties. It is concluded that the brown top-soils are due to periodic Holocene sedimentation followed by homogenization. The sandy loam and finer-textured Late Weichselian subsoils have a clear argillic horizon. These soils should be classified as Alfisols (Luvisols) rather than Plaggepts. (Abstract retrieved from CAB Abstracts by CABI’s permission)

The presence of supposedly primitive human tools along the upper reaches of the Kizil Irmak in Anatolia

The first indications of the existence of fluviatile terraces in E. Anatolia were reported recently by Izbirak (1962) and Ketin (1962). The present authors have made a rapid and superficial exploration of a terrace system containing a maximum of five to seven different levels along the upper reaches of the great Kizil Irmak or Red River between Sivas and Kayseri in E. Anatolia. This region partly overlaps, but lies mostly to the North of the region described by Izbirak. It appears that the terrace levels are fairly constant along the mentioned stretch of the river. They disappear suddenly farther downstream. With Izbirak the present authors are of opinion that the formation of these terraces is probably due to tectonic activities in the first place and only secondarily to climatic influences. One terrace level, the third (counting from the lowest level) consistently contained a very limited number of what the authors suppose to be primitive artefacts, among which there are some pebble-tools. These are described in the paper; they may indicate the presence of hominids in Turkey during the earliest part of the Pleistocene. In one case a fossil molar of a Hipparion was found in this third level in situ, partly covered by the same petrified red loam which also enveloped some of the supposed artefacts. No exact dating of the terraces is as yet possible, but it may be inferred that the oldest and highest ones are Tertiary, the one containing the artefacts perhaps lowermost Pleistocene, and the lowest ones young Pleistocene or even Holocene. Some time ago Izbirak (1962) published a geomorphological study of part of the region along the upper reaches of the Kizil Irmak in Turkey. Without being aware of the results of this study, the present authors made some observations in almost the same area. Although of a different nature these coincide very well with Izbirak's conclusions. Thanks to a grant-in-aid assigned to one of us by the Wenner-Gren Foundation for Anthropological Research at New York, the voyage, and the collecting of material in Turkey, was made possible. We would like to thank the authorities of this Foundation for the rendering of this financial aid; the authorities of the Netherlands Embassy at Ankara, and Professor A. A. Cense at Istanbul, should receive our thanks and gratitude for the aid and advice given us during our stay The region visited by us was part of the upper valley of the Kizil Irmak, the Halys river of ancient times, lying between the cities of Sivas and Kayseri. Our observations began immediately downstream from Sivas at both sides of the river over a continuous stretch of approximately 20 kilometres. Lower downstream a number of traverses at right angles to the river valley's axis was made.

Nouvel essai de correlation des terrasses rhodaniennes

Reconstruction of the Quaternary terraces of the Rhone (southeast France) reveals three or possibly four levels between the Rhone delta and the Rhone-Drome confluence. The age of the lowest terrace level--best exposed at Valence-Romans and upstream--is questionable. It may represent either the Wuerm or the Riss, or it may be divided between two different stades--neo-Riss and an older stade represented by the Leore-Fouillouse terrace. The middle terrace is Rissian and the highest terrace represents the Villafranchian. This phenomenon of uplifted terraces seems to be related to an isostatic uplift of blocks to compensate for the load of glacial ice. The continuity and extent of this phenomenon would explain the relative positions of the terraces, the older higher than the younger. Cross sections are included which show the recognized terraces. A correlation chart presents the Quaternary stratigraphy of Scandinavia, the alpine regions, the Sahara, central Africa, and Australia, and includes the major archaeological divisions.

Neue Schweizer Arbeiten zur Glazialmorphologie des Mittellandes

In this report the most important results of 5 new Swiss papers on glacial and periglacial landforms of the „Schweizer Mittelland" are published and discussed. These very good studies show the first geomorphological maps (1 : 25 000) of the „Mittelland" and for the first time they analyse periglacial forms in this region. A reiterated and radical change of accumulation and erosion is rejected within the melt-water-valleys during the Würm-glaciation. The thick accumulation of pebbles is recognized as „Vorstoßschotter". Nowhere it has been noticed that fluvio-glacial pebbles interfinger with end-moraines. The highest of the lower terraces is the built-up-level of the fluvioglacial accumulation of the Würm-time. For that reason the Würm-time seems to be undissected in the Hochrhein- and Aare-valley. This opinion is opposite to J. Hug, L. Erb, D. Kimball, F. E. Zeuner and R. Huber. The reviewer points out that real cut-terraces are only existing in relatively short parts of the valleys (C. Troll's „Trompetentälchen"). But for the rest you can find as a rule an erosional disconformity on every wider inset terraces-level, because there are secondary pebbles of about 5—8 m thickness interbedded in the older main accumulation of the Würm-time. The question whether there are floors running throughout the valley below the main terrace-level in the Hochrhein valley, cannot be answered by individual and relatively small sections of a melt-water-valley; least of all in the Hochrhein valley above the mouth of the Aare. For the development of deeper situated lower-terraces was controlled by the later advance of the Rhone-glacier at a time, when the other Swiss glaciers were receding. The reviewer substantially agrees with the Swiss scheme of periglacial forms and the classification of the Riss-time.