<p> Despite an increased interest in exploitation of hydrocarbon source rock resource plays, there remains an incomplete understanding of organic and inorganic component interaction within source rocks. Few studies have been conducted concerning the associations between organic and inorganic geochemistry for the purposes of understanding kerogen type, thermal maturity influence, and paleoredox setting. This investigation&rsquo;s goal was evaluating these relationships with samples from the Eagle Ford Formation using organic data, obtained by Rock-Eval pyrolysis and oxidation, and inorganic data, obtained using high-temperature and pressure leaching experiments. The study additionally tested various parameters for whole rock batch leaching, including time, temperature of leaching, and use of acids. The most successful leaching technique was applied to samples that (1) had first been subjected to Rock-Eval pyrolysis, at three different maximum temperatures (450&deg;C, 550&deg;C, and 650&deg;C), as well as (2) samples that had not been subjected to pyrolysis. As different kerogen fractions were destroyed at these different temperatures, variances in elemental concentrations leached from these samples could be attributed, at least partially, to these fractions. Using this approach, the lower molecular weight kerogen fraction contained most of the elements likely attributable to carbonates and sulfides associated with the kerogen (e.g., Ca, Mg, Mn, Mo, P, S, Sr, Zn). The higher molecular weight portion contained more elements probably attributable to clays, quartz, and other clastic minerals (e.g., Al, Fe, K, Si). An evaluation of the overall element chemistry of the rock paired with Rock-Eval parameters showed (1) major/trace elements varied according to amount and type of organic carbon in the Eagle Ford samples, (2) relative abundances of certain major/trace elements were useful proxies for bulk mineralogy and depositional environment, and (3) relationships between certain clay-related major and trace elements and T_max values suggesting clays and trace elements acted to catalyze the cracking of the kerogen.</p>

<p> Two hydrothermal experiments were performed using sandstone core material from the Norwegian North Sea with synthetic brines reacted at approximately 150&deg;C and 450 bars, temperature and pressure calculated to simulate a depth of burial of approximately 4 km. The results of the experiments were analyzed with geochemical modeling and with chemical and petrographic analyses. Geochemical modeling with several computer programs indicated that the experimental fluid was undersaturated with respect to K-feldspar, kaolinite, and illite, but supersaturated with respect to muscovite. Chemical analysis with inductively-coupled plasma mass spectrometry indicated that the fluid reached saturation with respect to K-feldspar. Petrographic analysis with scanning electron microscopy and energy-dispersive scanning indicated that changes took place over the course of the experiments in both the clay and non-clay mineral fractions, and this result was verified by X-ray diffraction analysis that indicated dissolution of both K-feldspar and illite and formation of muscovite. These converging lines of evidence indicate that significant changes took place in the clay mineral fraction of the experimental sandstone core material, reacted at realistic basin temperature, pressure and geochemical conditions, over the course of several weeks.</p>

<p> The submarine-fan-dominated, proximal Los Angeles basin contains interstratified hemipelagic strata coeval with the widespread Miocene Monterey Formation that accumulated in other California margin basins. Although more detritalrich and containing greater abundance of plagioclase and muscovite than more distal, outboard basins, a four-part compositional zonation is recognized in the fine-grained facies, similar to the stratigraphic succession of the Santa Barbara coastal area. In ascending stratigraphic order, these include a basal interbedded calcareous-siliceous zone, a phosphatic zone, a calcareous-siliceous zone, and an uppermost siliceous zone. To establish these zonations, 125 samples from five wells in a north-south transect across the western basin from East and West Beverly Hills, Inglewood, and Wilmington oil fields were analyzed for bulk chemical composition by XRF and quantitative mineralogy by XRD and FTIR. The mineralogic composition of the fine-grained detrital fraction makes use of geochemical equations for sedimentary components developed elsewhere unsuitable to the Los Angeles basin.</p>