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.
Trace impurities in Canadian oil-sands, coals and petroleum products and their fate during extraction, up-grading and combustion
National energy programs for the next two decades entail increased total consumption of fossil fuels in general and, in particular of portable fuels extracted from oil sands and shales and from lower quality coals. Improved fuel-upgrading and combustion technologies are recognized to be vital for minimizing environmental degradation caused by continental and global acid-rain precipitation from fossil-fuel impurities. A further consideration, however, is the fate of those trace-element co-contaminants of acid-rain such as heavy metals, which are present at lower concentrations (10−4–10−7) but may also be of environmental significance when 107 to 109 tons·y−1 are utilized on several continents. In this laboratory, INAA procedures have been adapted for the determination of 25–30 trace impurities in a variety of fuels and extracts including: S, V and Al, As, Ba, Br, Ca, Ce, Cl, Co, Cr, Dy, Eu, Fe, Hf, K, La, Mn, Na, Rb, Sb, Sc, Sm, Th, Ti, U. Samples were obtained of typical Canadian pumped crudes, and from several Canadian oil-sands and coal deposits (mostly bituminous and subbituminous) both in their natural states and after stages of extraction and upgrading. Also analyzed were fuels derived from them and the residues resulting from their refining and combustion. InAA of all fossil fuel extracts including light oils, viscous bitumen and such organic fluids could be performed under the same conditions as the parent substances: crude oils, oil-sands and coals, without any special sample preparation. Although no standard samples are routinely required because of the 1–2% long-term flux stability of the reactor, accuracy checks were performed periodically by reference to NBS-1632A standard coal and atomic absorption standard dilute solutions. Results obtained for the NBS coal SRM and the BAM flyash sample (1978) are also given. A wide range of trace impurities determined in the Canadian fossil fuels included some of those which are of particular significance in Canadian coals and their ashes (a STM standard ashing method). The ‘inorganic’ traces can also be grouped according to their fate during static combustion at 750°C.
Palaeocarpinus (Extinct Betulaceae) from Northwestern China: New Evidence for Paleocene Floristic Continuity between Asia, North America, and Europe
Spiny-bracted fruits of Palaeocarpinus Crane, a genus of Betulaceae previously known only from Europe and North America, have been discovered in the Paleocene of Altai, northwestern China. The fruits are found in association with abundant Corylus-like foliage and staminate catkins containing Corylus-like pollen. Because of problems distinguishing leaves of Corylus from those of extinct betulaceous genera, we place these leaves in the genus Corylites Gardner ex Seward & Holttum. The fruits, staminate catkins, pollen, and leaves from Altai were probably all produced by a single species. Palaeocarpinus orientalis is nearly identical in its morphology to Palaeocarpinus joffrensis from the Paleocene of North America except in the more rounded primary bracts of the associated staminate catkins. The species is less similar to Palaeocarpinus laciniata from the Paleocene of southern England.