Schwermineralverteilung und Alter pleistozäner mariner Sedimente in Mittelitalien. (Heavy mineral distribution and age of Pleistocene marine sediments in middle Italy)
In the Maremma, Alto Lazio, Middle Italy, heavy mineral studies were used to differentiate several types of beachrock and other marine sediments which are attributed to marine terraces of different age. (L'A.).
Fluvial deposits of the middle Kuiseb valley, Namibia
A variety of fluvial deposits of various ages occur in the middle Kuiseb valley in arid Namibia. The characteristics, lithology, spatial and altitudinal relationships and possible chronology of these fluvial deposits are considered. Conclusions
The apparent ages (Ar-Ar) suggest that initial oceanic plate disruption and tectonic emplacement of the Zagros and Makran ophiolites occurred in the middle Jurassic (170 Myr ago) with further displacements in the late Cretaceous (97 Myr and 89 Myr
ago). The similarity of the Jurassic age with ophiolite emplacement ages in Yugoslavia and Greece is possible evidence of a middle Jurassic collision of an early Mesozoic Tethyan ridge system with both eastern Europe and central Asia.
Progressive accretion in the Middle America Trench, Southern Mexico
The lithology and age distribution of a seismic unit characterised by landward dipping reflectors suggest progressive underthrusting and uplift of Trench deposits along the inner slope of the Middle America Trench. The fastest uplift and deformation
. The transgressive marine sediments onlap and overlie a 2700-yr-old middle Iron Age (Phoenician) tomb, which was built on a dark clay layer, containing a middle Bronze IIB (3750 yr B.P.) settlement. In post-Roman times the coastal zone at this site, both east
The recent discovery of a post-Roman-aged marine calcarenite terrace, at an altitude of 7 to 8 m at the ancient harbor of Akhziv, supports the hypothesis of oscillatory tectonic movements along the coastline of Israel during the late Holocene
Studies of the pedogenic iron oxyhydroxides in suites of latest Holocene to middle Pleistocene soils formed on alluvial deposits of the transverse ranges, Southern California, indicate that the content and composition of iron oxyhydroxide change
in a systematic manner. The results demonstrate that ironoxide analysis is useful for numerical age studies of non calcic soils and shows potential as an indicator of paleoclimates.
assemblages. Thus, it was possible to reconstitute the succession of different biotopes within the identified communitites. In this way, ten ecological groups were recognized within a Stellario-Alnetum of Atlantic age. From the samples of the MiddleAges, nine
Marine ostracodes from 50 localities were studied to determine the age and elevation of Pleistocene sea levels in the Atlantic coastal plain from Maryland to northern Florida. Using ostracode taxon and concurrent ranges, published planktic
biostratigraphic, paleomagnetic, and radiometric data, ostracode assemblage zones representing early (1.81.0my), middle (0.70,4my), and late (0.30.01my) Pleistocene deposition were recognized and used as a basis for correlation. Ostracode biofacies signifying
for the southeastern coastal plain: late Pleistocene, 2-10 m from Maryland to northern Florida| middle Pleistocene, 6-15 m in northern South Carolina: early Pleistocene, 4-22 m in central North Carolina, 13-15 m in southern North Carolina, and 6-27 m in South Carolina
A technique of alluviation rate estimation has been developed as a result of archaelogical and geomorphological studies carried out at archaelogical sites at the middle Oka floodplain dated from Early Neolithic to the MiddleAges. The technique
. The last major period of calcrete formation probably took place at least 14 000 years BP, under a climate drier than the present, between the close of the Middle Stone Age and the last major aeolian redistribution of the sands of Kalahari type
An interpretation is given of the structural setting and the sedimentary history of the Middle Miocene Quaternary deposits in eastern Crete (Ierapetra region). The present tectonic structure, characterized by normal faults in W-E and NE-SW
in a graben that extended over the southern half of the region. The sources of sediment supply then shifted from East to West and slices of sediments (in part of pre-Neogene age) slid from the uplifted blocks in the North to the central parts of the region
The AA. recommend the use of the terms numerical-age, calibrated-age, relative-age, and correlated-age. They also classify dating methods by type into sideral, isotopic, radiogenic, chemical and biological, geomorphic and correlation methods
. The use of absolute is inappropriate for most dating methods, and should be replaced by numerical . The use of date should be minimized in favor of age or age estimate . They recommend use of the abbreviations ka and Ma for mostages| calender dates can
be used were appropriate and Yr B.P. can be used for radiocarbon ages.
This study examines the dichotomy that C 14 ages for noncollagenous fossils are underestimated, whereas ages for collagenous fossil bones are more accurate. There is a high probability that amino acids from poorly preserved fossils will date younger
than the true age of the fossil and that the radiocarbon dates could be decreased by 2 000 to 9 000 yr or more. By existing AMS techniques, the measured ages would probably be Holocene, not Pleistocene.
Fission-track ages of tuff layers related to the Pliocene-Pleistocene boundary on the Boso Peninsula, Japan
Four additional fission-track ages (one from the Kurotaki Formation and three from the Amatsu Formation) are presented here. These fission-track ages provide restriction for the controversy on magneto-biostratigraphy.
On the ice age glaciation of the Tibetan Highlands and its transformation into a 3-D model
The AA. present an interdisciplinary study on data and modeling intercomparison, concerning the possible existence of a Tibetan ice sheet and its climatological implications during the ice age.