Rare earth elements,iron formations and sea water

Iron formations probably formed as chemical sediments when an Fe-rich solution entered the sedimentary environment. The REE patterns of such sediments are affected by the amount and type of precipitating and detrital phases, the REE pattern of the iron source solution, the REE pattern of the sea water into which the solution flows, and the mixing which takes place between input solution and sea water. What is known about the different types of iron formation suggests that all of these factors may vary from one type to another. Therefore, variations in REE patterns cannot be attributed solely to changes in sea water REE patterns. Comparison of the REE patterns of Archean and Ordovician iron formations of the Algoma type shows that similar iron formations have similar REE patterns regardless of age. This implies similar genetic histories.     

Great-circle Rayleigh wave attenuation and group velocity,Part I: Observations for periods between 150 and 600 seconds for seven great-circle paths

Rayleigh wave attenuation coefficients and group velocities have been estimated for seven great-circle paths. The attenuation coefficient measurements cover the period range from 100 to 500 s, and group velocities the range from 100 to 600 s. Global average group velocities and attenuation coefficients have also been estimated for these period ranges. The spread of the individual path group velocities for 20-s averaging windows centred at 290, 250, 210, 180 and 150 s is less than 0.034, 0.028, 0.024, 0.048 and 0.071 km/s, respectively. Global average attenuation coefficients, when combined with global average group velocities, show that Q for Rayleigh waves has an approximately constant value of about 145 for periods between 150 and 220 s and slowly increases to a value of about 200 at a period of 400 s.     

Comparison of Foraminiferal, Coccolithophorid, and Radiolarian paleotemperature equations: Assemblage coherency and estimate concordancy

The Imbrie-Kipp method of paleotemperature estimation is rigorously tested by comparing Atlantic temperature equations independently derived from the microfossils of three biotic groups: the Foraminifera, Coccolithophorida, and Radiolaria. This method consists of two steps: factor analysis of the modern sea-bed data of the individual groups which resolves discrete biogeographic assemblages and regression analysis of the modern assemblage data with observed sea-surface temperature data to obtain paleotemperature equations. Assemblage biogeography shows a simple subdivision into warm (low latitude) and cold (high latitude) for all biotic groups. Between biotic groups there is greater similarity among high-latitude assemblages than low-latitude ones. Correlating the assemblage data with observed sea-surface temperatures to produce temperature distribution patterns shows differences of less than 2°C in their optimum and critical temperatures. Regression analysis produced accurate temperature equations for each biotic group, all with standard errors of estimate of less than or equal to 2°C. Multiple correlation coefficients were all greater than 0.970. Applying these equations to two multiple biotic data sets (the modern and ice-age sea-bed data) and comparing their temperature estimates using the standard error pooled, shows over 87% concordancy for both data sets. Unlike the modern data, the discordancy among temperature estimates of the ice-age data shows a distinct geographic distribution; its cause is believed to be oceanographic, a difference in the water-mass structure between the modern and ice-age ocean.     

A method for the study of the zonal kinetic energy balance in the atmosphere

Summary The atmospheric balance of the kinetic energy of the zonally averaged zonal motion is investigated from five years of daily data at 800 stations for the northern hemisphere. The basic equation for such energy is used, together with the simplifying assumption that the frictional destruction is due in the main to stresses acting across horizontal surfaces, being thus presumably related to the vertical shear of the mean zonal wind, although no further details are needed in the analysis. The five-year averages of various terms as well as their seasonal means appear to give reasonable results.The research reported in this paper was sponsored by the U.S. National Science Foundation under Grant No. GA-1310X.     

Lime incrustingHapalosiphon intricatus (Cyanophyceae) and phosphate availability in a Florida cave

Hapalosiphon intricatus (Cyanophyceae) with lightly calcified sheaths, is the dominant filamentous alga reported from a humid, dimly-lighted limestone cave in northcentral Florida (USA). Within the limestone substrate, hydroxyapatite is the form of the phosphate mineral providing nutrient to the algae. Florida Agricultural Experiment Station Journal series No. 4381.