Geochemical evidence of pollutants from coalfired generating stations in late Pleistocene palaeosols in the Dalijia Shan, northwestern China
Surface palaeosols in two tills and a diamicton from an area in northwestern China were analysed for geochemical pollutants. Elevated levels of Br, As and Sb indicate that pollution from coal-burning and/or coal-fired electricity generating stations is delivered by aeolian transport into palaeosols dating from the last glaciation. Because the climate in the field area is sub-humid (precipitation <760 mm) the relative movement of soluble elements in palaeosols dating from early and late stades of the last glaciation is not expected to be high. The glacial and aeolian parent materials of the palaeosols indicate differences that are probably related to their source areas and to the incorporation of geochemical pollutants.
Extractable FeAl and geochemistry of late pleistocene paleosols in the Dalijia Shan, western China
Surface paleosols in two tills and a diamicton were analyzed for extractable Fe and Al and to determine if elemental distributions would assist in the interpretation of past and present soil-forming environments. Extractable Fe and Al distributions indicate that leaching (based on movement of Fep) is pronounced in paleosols dating from the last glaciation. Moreover, analysis of oxalate extractable Fe and dithionite extractable Fe (FeoFed) shows that amorphous Fe increases with depth in all three paleosola with similar rates of conversion to crystalline Fe. Data for extractable forms of Al-oxides show somewhat higher values of pyrophosphate extractable Al with time. Because the climate in the field area is dry (precipitation < 760 mm) the amounts of crystalline Fe (Fed) in paleosols dating from early and late stades of the last glaciation are not high. Using values in the paleosol sola the difference amounts to 0.4%. Pyrophosphate extractable Fe shows a pronounced increase in the two older paleosols that may result from interstadial paleoclimates of the last glaciation. The geochemistry of the glacial and aeolian sediments (paleosols) indicates differences that they are probably related to the source areas of the different parent materials.
Archaeology and mud wall decay in a West African village
Abstract A detailed study of the processes of deterioration of mud walls and of the physical evolution and devolution of a contemporary West African village is seen to facilitate the location of decayed mud structures at a nearby archaeological site. Various climatic and pedological conditions at the site make it unlikely that such walls will be discerned. The archaeologist wishing to obtain the fullest and least biased picture of the settlement configuration of the ancient community should therefore heed all the inferential lessons to be had from a focused ethnographic investigation. Given similar climatic situations and practices of house construction, taphonomy and ethnographic analogies may both be necessary for a valid reconstruction of an archaeological settlement.