Daniel E. Kile

Partition of Nonpolar Organic Pollutants from Water to Soil and Sediment Organic Matters

The partition coefficients (K oc ) of carbon tetrachloride and,1,2-dichlorobenzene between normal soil/sediment organic matter and water have been determined for a large set of soils, bed sediments, and suspended solids from the United States and the Peoples Republic of China. The K oc values for both solutes are quite invariant either for the soils or for the bed sediments; the values on bed sediments are about twice those on soils. The similarity of K oc values between normal soils and between normal bed sediments suggests that natural organic matters in soils (or sediments) of different geographic origins exhibit comparable polarities and possibly comparable compositions. The results also suggest that the process that converts eroded soils into bed sediments brings about a change in the organic matter property. The difference between soil and sediment K oc values provides a basis for identifying the source of suspended solids in river waters. The very high K oc values observed for some special soils and sediments are diagnostic of severe anthropogenic contamination

On geological interpretations of crystal size distributions: Constant vs. proportionate growth

Abstract Geological interpretations of crystal size distributions (CSDs) depend on understanding the crystal growth laws that generated the distributions. Most descriptions of crystal growth, including a population-balance modeling equation that is widely used in petrology, assume that crystal growth rates at any particular time are identical for all crystals, and, therefore, independent of crystal size. This type of growth under constant conditions can be modeled by adding a constant length to the diameter of each crystal for each time step. This growth equation is unlikely to be correct for most mineral systems because it neither generates nor maintains the shapes of lognormal CSDs, which are among the most common types of CSDs observed in rocks. In an alternative approach, size-dependent (proportionate) growth is modeled approximately by multiplying the size of each crystal by a factor, an operation that maintains CSD shape and variance, and which is in accord with calcite growth experiments. The latter growth law can be obtained during supply controlled growth using a modified version of the Law of Proportionate Effect (LPE), an equation that simulates the reaction path followed by a CSD shape as mean size increases.

On the origin of size-dependent and size-independent crystal growth: Influence of advection and diffusion

Abstract Crystal growth experiments were conducted using potassium alum and calcite crystals in aqueous solution under both non-stirred and stirred conditions to elucidate the mechanism for size-dependent (proportionate) and size-independent (constant) crystal growth. Growth by these two laws can be distinguished from each other because the relative size difference among crystals is maintained during proportionate growth, leading to a constant crystal size variance (β2) for a crystal size distribution (CSD) as the mean size increases. The absolute size difference among crystals is maintained during constant growth, resulting in a decrease in size variance. Results of these experiments show that for centimeter-sized alum crystals, proportionate growth occurs in stirred systems, whereas constant growth occurs in non-stirred systems. Accordingly, the mechanism for proportionate growth is hypothesized to be related to the supply of reactants to the crystal surface by advection, whereas constant growth is related to supply by diffusion. Paradoxically, micrometer-sized calcite crystals showed proportionate growth both in stirred and in non-stirred systems. Such growth presumably results from the effects of convection and Brownian motion, which promote an advective environment and hence proportionate growth for minute crystals in non-stirred systems, thereby indicating the importance of solution velocity relative to crystal size. Calcite crystals grown in gels, where fluid motion was minimized, showed evidence for constant, diffusion-controlled growth. Additional investigations of CSDs of naturally occurring crystals indicate that proportionate growth is by far the most common growth law, thereby suggesting that advection, rather than diffusion, is the dominant process for supplying reactants to crystal surfaces.

Crystal chemical variations in Li- and Fe-rich micas from Pikes Peak batholith (central Colorado)

Abstract The crystal structure and M-site populations of a series of micas-1M from miarolitic pegmatites that formed within host granitic rocks of the Precambrian, anorogenic Pikes Peak batholith, central Colorado, were determined by single-crystal X-ray diffraction data. Crystals fall in the polylithionitesiderophyllite- annite field, being 0 ≤ Li ≤ 2.82, 0.90 ≤ Fetotal ≤ 5.00, 0.26 ≤ [6]Al ≤ 2.23 apfu. Ordering of trivalent cations (mainly Al3+) is revealed in a cis-octahedral site (M2 or M3), which leads to a lowering of the layer symmetry from C12/m(1) (siderophyllite and annite crystals) to C12(1) diperiodic group (lithian siderophyllite and ferroan polylithionite crystals). On the basis of mean bond length, the ordering scheme of octahedral cations is mostly meso-octahedral, whereas the mean electron count at each M site suggests both meso- and hetero-octahedral ordering, the calculated mean atomic numbers being M1 = M3 ≠ M2, M2 = M3 ≠ M1 and M1 ≠ M2 ≠ M3. As the siderophyllite content increases, so do the a, b, and c unit-cell parameters, as well as the refractive indices, primarily nβ. The tetrahedral rotation angle, α, is generally small (1.51 ≤ α ≤ 5.04°) and roughly increases with polylithionite content, whereas the basal oxygen out-of-plane tilting, Δz, is sensitive both to octahedral composition and degree of order (0.0 ≤ Δz ≤ 0.009 Å for siderophyllite and annite, 0.058 ≤ Δz ≤ 0.144 Å for lithian siderophyllite and ferroan polylithionite crystals).

Effects of polar and nonpolar groups on the solubility of organic compounds in soil organic matter.

Vapor sorption capacities on a high-organic-content peat, a model for soil organic matter (SOM), were determined at room temperature for the following liquids: n-hexane, 1,4-dioxane, nitroethane, acetone, acetonitrile, 1-propanol, ethanol, and methanol. The linear organic vapor sorption is in keeping with the dominance of vapor partition in peat SOM. These data and similar results of carbon tetrachloride (CT), trichloroethylene (TCE), benzene, ethylene glycol monoethyl ether (EGME), and water on the same peat from earlier studies are used to evaluate the effect of polarity on the vapor partition in SOM

CRYSTAL GROWTH MECHANISMS IN MIAROLITIC CAVITIES IN THE LAKE GEORGE RING COMPLEX AND VICINITY, COLORADO

Pegmatites are characterized by crystals of very large size. Many people have assumed that these crystals attained their size as a result of long periods of growth from slowly cooled magmas. Some pegmatites, however, are intimately associated with fine-grained aplites (commonly along the footwall portions of the dikes), for which grain sizes are suggestive of much faster cooling, nucleation, and crystal growth. The contrast in crystal size between the genetically related coarse-grained pegmatite and fine-grained aplite remains one of the intriguing enigmas with respect to the genesis of these pegmatite-aplite dikes. Many of the pegmatites in San Diego County have layered aplites and were first described in detail by Jahns and Tuttle (1963). Layered portions of pegmatite-aplite dikes are locally known as “line rock.” This paper presents a conductive cooling-crystallization model for four composite pegmatite-aplite dikes in San Diego County, California: the George Ashley, Stewart, and Mission dikes in the Pala Pegmatite District and the Himalaya dike in the Mesa Grande Pegmatite District. The aplitic portions of all ABSTRACT

Crystal structure and chemistry of lithium-bearing trioctahedral micas-3T

Chemical analyses and crystal structure refinements were performed on lithian siderophyllite-3 T crystals from granitic pegmatites of the anorogenic Pikes Peak batholith (Colorado) to characterize the crystal chemistry and relations with trioctahedral lithium-bearing micas showing different stacking sequences. Chemical data show that the studied samples fall on the siderophyllite-polylithionite join, closer to the siderophyllite end-member. Single-crystal X-ray refinements were carried out on three samples (two of which were taken from core and rim of the same crystal) in space-group P 3 1 12 (the agreement factor, R obs , varies between 0.034 and 0.036). Mean bond distances and mean electron counts of M1, M2 and M3 octahedral sites indicate an ordered cation distribution with M1 and M3 positions substantially larger than M2. In the sample with the largest iron content, the M2 mean electron count increases as well as the mean distance, whereas remains smaller than or . The tetrahedral cation-oxygen atom mean distances range from 1.614 to 1.638 A and from 1.663 to 1.678 A for T1 and T2 sites, respectively, being consistent with Al 3+ enrichment in the T2 sites. The tetrahedral rotation angle, α, is generally small (3.1 ≤ α ≤ 4.6°) and decreases with siderophyllite content. As Fe increases, the T1 tetrahedron becomes flatter (112.4 ≤ τ T1 ≤ 110.5°), whereas T2 tetrahedron distortion appears unchanged (110.7 ≤ τ T2 ≤ 110.9).

Simmonsite, Na2LiAlF6, a new mineral from the Zapot amazonite-topaz- zinnwaldite pegmatite, Hawthorne, Nevada, U.S.A.

Abstract The crystal structure of sogdianite, hexagonal, a = 10.053(1), c = 14.211(2) Å, V= 1243.8(4) Å3, space group = P6/mcc, Z = 2, has been refined to an R index of 2.0% using 607 observed (|Fo| > 5σ|F|) reflections collected with an automated four-circle diffractometer using MoΚα X-radiation. Sitescattering refinement and electron-microprobe analysis indicate the composition (Zr0.76Ti4+0.38Fe3+0.73 Al0.13)∑ = 2(❐1.15Na0.85)∑ = 2K[Li3Si12O30]. The T2 tetrahedron is completely occupied by Li, and all Al occurs at the octahedrally coordinated A site. The bond length is compatible with all Fe being in the trivalent state. There is no significant positional disorder of the A-group cations, in accord with the absence of H2O in sogdianite. Single-crystal X-ray precession photographs of sogdianite show the presence of diffractions that are incommensurate with the sogdianite diffraction pattern. The relative intensity of the incommensurate diffractions increases with the degree of apparent alteration of sogdianite (clear → turbid → murky), suggesting that sogdianite is altering to, or possible exsolving, a second phase, probably zektzerite.

Occurrence and Genesis of Thunder Eggs Containing Plume and Moss Agate

K nown since the late 1800s, the thunder-egg beds near Del Norte, Colorado, have provided the collector in recent times with world-class plume and moss agate. Plume agate represents the ultimate in aesthetically arranged featherlike assemblages, whereas moss agate can manifest a bewildering variety of forms, including tubes as well as randomly intertwined fibers. These inclusions exhibit a wide range of color, from white to black and from brown to orange and red. Described as “plant-like” by Brown (1957), they are typically enclosed in chalcedony, which comprises the interior of spherical nodules commonly known as thunder eggs. Plume and moss structures are three dimensional in form, in contrast to the principally two-dimensional denhitic growths that occur between bands of chalcedony, such as those found in Montana “moss” agate. Thunder eggs are generally defined as nodular structures (Staples [I9651 emphasized that they should be considered structures, not “rocks”) that are formed within high-silica extrusive volcanic rocks or welded tuffs, with the silica content of the rock ranging from 75 to 80 percent (Dake 1951; Renton 1951; Staples 1965). Accordingly, thunder eggs are not found in comparatively silica-poor, basaltic rocks such as those capping the Table Mountains near Golden, Colorado. The nodules are approximately spherical in shape and have an exterior shell of rhyolite that is more silicified than the host rock (Renton 1951). Staples (1965) further refines this definition by describing surface textures ranging from smooth to wartlike, with intersecting ribs that encircle the nodule. Ross and Smith (1 96 1) simply define thunder eggs as uncommonly large lithophysae (i.e.. hollow gas cavities; Greek derivation = “stone bubble”) that develop in a welded tuff (welded fufs are composed of a “plastic” volcanic ash that becomes indurated, or fused, by the internal heat that is inherent in the erupted rock [Thrush 19681). The thunder egg is composed of a shell of rhyolite that has devitrified (a process of crystallization of the volcanic glass) and in which spherulites appearing as radiating growths of acicular crystals and/or lithophysae occasionally develop. By traditional definition it has a central cavity that is partly to completely filled with chalcedony, opal, or quartz and that may exhibit a geometrical, star-shaped form. The chalcedony may be banded or it may contain “pseudo-algal” structures that are

Zeolites and Associated Minerals from the Table Mountains near Golden, Jefferson County, Colorado

eolites, the theme of the Denver 2004 Gem and Mineral Show, are well represented in Colorado. In particular, the Table Mountains near Golden have been known as a source of excellent specimen-quality zeolites and associated minerals for more than 115 years. Although overshadowed in recent years by the tremendous quantity of material from India, this classic Dana locality is nonetheless world-class with respect to the size, variety, and quality of thomsonite. The Table Mountains additionally feature other rare zeolites in good quality, such as levyne and cowlesite. It has been nearly sixteen years since the last comprehensive article on this locality was published (Kile and Modreski 1988), and although many outstanding specimens have since been recovered, there have been no reported new species, and no substantial revision to the paragenetic sequence as presented earlier has been found necessary. Accordingly, much of the descriptive geology and mineralogy has been abstracted from the earlier report; the present