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Some black shales contain >1000 ppm Mo, comparable to conventional ores. These include Mo-rich Pennsylvanian black shales that were deposited rapidly near shore as epeiric seas inundated pear swamps, while coeval beds, less enriched in Mo, accumulated slowly offshore. Concentration of Mo probably resulted from retention of the metal by organic matter in acidic pore fluids characteristic of nearshore deposits. Thus, in Pennsylvanian shales where organic productivity is significant, Mo variations may be used to distinguish nearchore from offshore conditions. Enrichments in Mo occur in black shales of other ages; therefore a high Mo content may be useful as a general criterion for nearshore environments and other conditions with strong pH gradients.

A new phase composed mainly of Mo, S, and C and referred to herein as MoSC occurs widely in organic-rich, metalliferous Cambrian black shales in south China. MoSC, which has previously been referred to as jordisite, has been studied by scanning electron microscopy (SEM), electron microprobe analysis (EMPA), transmission electron microscopy (TEM), powder X-ray diffraction, (XRD), extended X-ray absorption fine structure (EXAFS), and catalytic activity. TEM data show MoSC to have a layered structure, with packets resembling molybdenite and graphite-like carbon that average five layers in thickness. Analytical data are consistent with an idealized formula of [Mo.sub.3][S.sub.6][C.sub.10] but it commonly contains 1-3 wt% each of Fe, Ni, and As so that its composition may be better approximated by the formula [(Mo,Fe,Ni).sub.3][(S,As).sub.6][C.sub.10]. Selected area electron diffraction (SAED) patterns show a small number of broad, inhomogeneous rings corresponding to randomly oriented layers arranged in subspherical cells. A single broad, weak peak corresponds to a 10-11 [Angstrom] layer spacing in powder XRD diffraction patterns. Pseudomorphism after fossil bacteria implies an origin by replacement of sedimentary organic material. In its chemical properties and structure, MoSC resembles synthetic compounds used as catalysts for hydrodesulfurization (HDS) in the petrochemical industry. The large surface-to-volume ratio for MoSC may be an important factor in its relatively strong HDS catalytic activity. Cotype samples of jordisite from Germany, previously thought to be amorphous MO[S.sub.2], were also studied by SEM and TEM. Jordisite occurs as sequences of a few curved layers that form subspherical units, with an appearance remarkably like that of MoSC. However, the layer spacing is ~6 [Angstrom], like that of molybdenite. The ratio of Mo:S is ~1:2, and no carbon was detected, although it coexists with kerogen. Jordisite is thus confirmed to be a form of Mo[S.sub.2], but because powder diffraction-like SAED patterns were obtained, it is not amorphous.

Fluid-inclusion studies of radiometrically dated (U/Pb, Th/Pb) calcite samples document the presence of hydrothermal fluids at ca. 251, 137, 67, and probably 39 Ma within the Tri-State Zn-Pb mining district of Missouri, Kansas, and Oklahoma. Fluid inclusions indicate minimum temperatures and equivalent salinities ranging from highs of 122 [degrees] C and 24 wt% NaCl ca. 251 Ma to lows of 52 [degrees] C and 0 wt% NaCl ca. 39 Ma. The two earliest calcites contain primary petroleum inclusious, but these are absent in samples younger than ca. 137 Ma. When combined with information on metal-rich shales, paleomagnetism, and modern groundwater flow, our results are most readily explained by periodic influxes of hydrothermal fluids of diverse compositions for [is greater than] 200 m.y. and sporadic migration of hydrocarbons for at least 100 m.y. in the southern Midcontinent. Keywords: fluid inclusions, U/Pb and Th/Pb dating, Tri-State lead-zinc ores, hydrocarbons, regional fluid flow.

Quantitative relationships among social, economic, and climate parameters, and energy consumption for Chinese provinces, provide data for regression models' estimated rates of energy consumption and emission of polycyclic aromatic hydrocarbons (PAHs) by county. A nonlinear model was used for domestic coal combustion with total population and annual mean temperature as independent variables. Linear regression models were utilized for all other types of fuel consumption. Monte Carlo simulation demonstrated that emission factors, rather than the regression modeling, constitute the main source of uncertainty in prediction. Models were validated using available energy data of several northern and southern counties of China from the literature. The total PAHs produced by each county is approximately equivalent to the sum of the total emission from energy, coke, and aluminum production.