Burial Of Sediments Research Articles

Monitoring Local Subsidence in Areas of Potential Geopressured Fluid Withdrawal, Southwestern Louisiana: ABSTRACT

ABSTRACT Growth faulting, rapid deposition, and deep burial of sediments in south Louisiana have resulted in the abnormal pressurization of pore fluids within some sedimentary units. Fluid production from geopressured sandstones may result in pore-pressure reductions, clay compaction, and land-surface subsidence Subsidence is being monitored at the U.S. Department of Energy's Sweet Lake, Parcperdue, and Rockefeller Refuge geopressured-geothermal prospects in southwestern Louisiana. Reservoir-defining growth faults were extrapolated to the land surface, surface lineations were mapped from aerial photographs, and historical elevation surveys were compared to obtain base-line subsidence rates. Data from the Sweet Lake prospect indicate that no correlations exist between subsidence anomalies and lineations or fault projections. Subsidence here is probably a result of normal sediment compaction, salt domerelated land-surface adjustments, and/or historical subsurface fluid production. Conversely, a good correlation exists between the Parcperdue subsidence profile and the extrapolated updip extensions of mapped subsurface faults. Historical land-surface subsidence north of the Parcperdue prospect may have resulted from down-to-the-coast slumping along these growth faults which define the prospect. Subsidence at the Rockefeller Refuge prospect ranges from virtually zero on the eastern end of the prospect to 50 mm on its western end. The gradation may be due to oil- and gas-associated fluid withdrawals or land management variations. A subsidence analysis near Lake Charles, Louisiana, suggests that a more extensive historical record of leveling data could provide a more qualifying subsidence record. Repeated leveling surveys at the geopressured-geothermal prospects should aid in determining the causes of subsidence before and after depressurization of the geopressured aquifers.

Plate-Tectonic Controls on Diagenesis

Plate tectonics can be used as a framework for relating diagenesis to geological and geophysical parameters: regional tectonics, including rates of subsidence, uplift and deformation; volcanism and plutonism; heat flow; and transport of formation waters. These parameters affect diagenetic variables: the primary detrital-chemical assemblage; composition of early interstitial waters; rates and depth of burial; length of time buried; geothermal and pressure gradients; and oscillatory vertical movements. The consequences of changes in the values of these variables are illustrated for the diagenesis of the silica polymorphs, Ca- and Mg-carbonates, zeolites, and clay minerals. The unstable nature of biogenic opaline silica components of the primary assemblage leads to successive polymorphic inversions, ultimately to microcrystalline quartz chert. Pressure and temperature control the solubility and rate of inversion of all silica polymorphs. Carbonate systems also are controlled both by the presence of unstable phases (Mg-calcite, aragonite) in the primary assemblage and the effects of pressure and temperature on solubility. In later diagenesis oscillatory movements lead to reversals or replacements of carbonates. Zeolites are derived from the marine and nonmarine alteration of volcaniclastics. Burial, accompanied by pressure and temperature increases, produces the diagenetic zeolite facies. Clay minerals of both terrigenous and marine volcanic derivation are responsive to ion-exchange and silicate reconstitution reactions in early interstitial waters. Pressure and temperature increases lead to the stable chlorite-illite assemblage under deep-burial conditions. Plate-tectonic environments are for simplicity classified as mid-ocean ridge, trailing edge (passive), subduction, continent-continent collision, rift valley, and intraplate (cratonic). Mid-ocean ridges are sites of thin pelagic sediment accumulation affected by high heat flow, hydrothermal activity, and volcanic activity, followed by decreasing heat flow and slow burial as the sediments spread from the ridge. Geothermal gradients are higher in these marine sediments than they are on the continents. Muddy and sandy sediments remain largely unlithified except for layers of chert and limestone. Trailing edges are characterized by lowered heat-flow rates and reduced geothermal gradients, as well as rapid subsidence and burial of terrigenous detrital and chemical sediment after the initial opening phase in which evaporites and heavy metal deposits are formed. The resulting rocks are moderately cemented and lithified by carbonate and quartz and, in deeper zones, have the stable chlorite-illite mineral pair. Volcaniclastics are rare, as are zeolites. Subduction zones, a diverse group of subenvironments, are regions where low heat flow, rapid subsidence, and burial, accompanied by crumpling, operate on turbidites and pelagics, together with large amounts of volcaniclastic debris from nearby island arcs. Zeolites, smectites, and low-temperature-high-pressure mélanges, including ophiolites, are produced. Continent-continent collisions produce enormous quantities of terrigenous detritus deposited in both terrestrial and marine environments, from intermontane basins with subaerial exposure and meteoric water infiltration to submarine fans and plains. Geothermal gradients are low, sedimentation and burial are rapid, and diagenesis is mild, except in sections that have remained deeply buried for 100 m.y. or more. Diagenesis of rift-valley sediment is related to the abundance of volcaniclastics, mixed with alluvial and lacustrine deposits, all buried rapidly in regimes of high heat flow and hydrothermal activity. Intraplate diagenesis is the result of low subsidence and sedimentation rates in low continental heat-flow regimes. But oscillatory movements are frequent, and complex parageneses of authigenic mineral replacements indicate multiple changes in formation-water composition. A uniformitarian approach to this subject is valid only for the Phanerozoic, for present-ay patterns of plate tectonics may not have existed during earlier times when heat flow from the interior was differently distributed.

Geochemical mass balances for mercury in a Canadian fjord

The Saguenay River and Fjord comprise part of the St. Lawrence drainage basin of eastern Canada. High levels of total Hg occur in the sediments (0.25–218 mg kg −1), in suspended particulate matter (1–50 mg kg −1), in water (0.07–0.38 μg 1 −1), and in certain species of fish (0.5–10 mg kg −1). Most of the Hg appears to originate from industrial wastes. A total of 105 tonnes (t) Hg above natural levels are estimated to reside in the sediments of the Saguenay River and Fjord and a further 12 t Hg appear to have escaped and been subsequently deposited in the sediments of the adjacent St. Lawrence Estuary. These quantities represent about 81% of the probable industrial discharges of Hg to the water prior to 1971 when federal government effluent regulations were imposed on the chlor-alkali industry. Despite regulated Hg discharges after 1971, analyses carried out in 1973 suggest that a minimum of 7.6 t Hg a −1 appeared to be still passing through the fjord. Natural inputs and regulated industrial discharges account for 2.8 t a −1 and the remainder (4.8 t a −1) appear to be due to methylation (0.5 t a −1) and part of the untraceable Hg losses reported by industry (∼ 4–7 t a −1) in the area. The rate of Hg transfer to the sediments is controlled by the flux of terrigenous organic material into the Fjord. A recent decline in this flux has allowed more Hg to remain in the water column so that flushing has assumed greater importance. Decontamination of the Fjord will occur by the burial of Hg-rich sediments and flushing after the curtailment of industrial inputs. It is estimated that sediment decontamination will take decades while the water should return to near-natural levels within two years following the cessation of industrial Hg injections. The recovery rate of biota from Hg contamination will then depend upon their habitat and food sources.

Load structures at the sediment-saprolite boundary, Fall Line, Maryland

The field relationship of Lower Cretaceous sedimentary rocks to saprolite along the Fall Line provides new information about sedimentation and saprolite burial in Howard County, Maryland. The response that the saprolite, which was formed from a felsic gneiss, has made to the overlying sediment suggests that (1) the crystalline rock had weathered to saprolite before sediment emplacement, (2) the sediment was deposited by a highly erosive agent, (3) the saprolite was water saturated and deformed plastically during sedimentation, and (4) later reorientation of the sediment-saprolite deformation structures took place, probably during sediment compaction. Sedimentary petrology, sediment-saprolite contacts, and reverse density and injection structures along the sediment-saprolite boundary seem to rule out a Quaternary periglacial origin (congeliturbations) or any other origin involving saprolitization later than sedimentation. The field relationships and sedimentological analysis indicate synsedimentary deformation of the saprolite during Early Cretaceous time.

Isotopic evidence for source of diagenetic carbonates formed during burial of organic-rich sediments

Organic matter is modified by several processes operating at different depths during burial diagenesis: (1) sulphate reduction; (2) fermentation; (3) thermally-induced decarboxylation, and so on. CO2, one common product of each, can be distinguished by its carbon isotope composition: approximately (1) −25‰, (2) +15‰, (3) −20‰ relative to PDB. These values are preserved in diagenetic carbonates of the Upper Jurassic Kimmeridge Clay. Independent corroboration of the relative dominance of each process within specific depth intervals is given by the isotopic composition of incorporated oxygen which is temperature dependent (1) 0 to −2‰, (2) −1.5 to −5‰,(3) −3.5 to −7.0‰.

Structure and Evolution of Bering Sea Shelf South of St. Lawrence Island

The virtually featureless Beringian shelf south of St. Lawrence Island is underlain structurally by at least 14 basins. Encompassing a total area of more than 300,000 sq km, most of the basins are either elongate structural sags, grabens, or half (asymmetric) grabens beneath the outer shelf. The regional trend of these basins is northwest, parallel with that of the continental margin. Two of the basins, St. George and Navarin, contain 7 to 10 km of Upper Cretaceous(?) and Cenozoic sedimentary strata. A major divergence in dip of beds in the upper half of the sedimentary section may reflect an abrupt shelf-wide change in the rate of sedimentation and/or subsidence, probably during the Miocene. The outer sub-shelf basement grabens and adjacent ridges (horsts) are bounded by high-angle normal faults that exhibit growth-type structure. St. Matthew basin, an elongate, southwest-trending feature of the inner shelf, lies along the offshore expression of the Kaltag fault of western Alaska. The Kaltag fault, like the Denali fault in southwestern Alaska, does not extend to the outer Bering Sea shelf but ends or turns parallel with the margin within the inner shelf. The inner shelf is underlain by a broad basement high, Nunivak arch, the seaward half of which is characterized by an arcuate belt of high-frequency and high-amplitude magnetic anomalies. This zone of intense magnetic anomalies along the shelf is probably the signature of a Mesozoic magmatic arc that extends from southwestern Alaska to eastern Siberia and consists of Jurassic to Cretaceous plutonic and volcanic rocks. We speculate that this magmatic arc resulted from oblique convergence and subduction in the Mesozoic between the Kula(?) and North American plates along the eastern Beringian margin. Folding and uplift in the area of the present outer shelf occurred contemporaneously with magmatism along the inner shelf. Plate convergence apparently ceased by the end of the Mesozoic or t e beginning of the Cenozoic. Subsequently, the foldbelt underlying the outer shelf was eroded extensively and rifted extensionally to form large, deep basins. On the average, the shelf has subsided more than 1.5 km. Subsidence and sediment burial of the eroded orogen formed the modern Beringian shelf.

An experimental approach to lithification textures

ALTHOUGH observations on changes taking place during the compression of monominerals have been published1–3, little or no information exists on the textural aspects of compression affecting granular sediments. The main reason for this lack of textural information is presumably a technical problem. Ever since the pioneering investigations conducted by Bridgman, equipment used in high pressure experiments in geology has consisted of hydraulic cylinders in combination with completely closed, thin-walled test-tube bombs compressed by the surrounding oil in the hydraulic system4,5. The triaxial cell used in tectonic studies, allowing control over the three stress directions, uses massive samples jacketed to prevent the pressure medium from direct contact with the sample4. Triaxial studies have been performed only with massive samples, that is, already lithified rocks. No tests have yet been described involving thin sectioned samples of granular sediments subject to compression. Essentially, such experiments would reveal the mechanical aspects of the burial of natural sediment.

Trends “Late Diagenetic Theory of Petroleum Genesis”-A Review

Recently, the theory of late diagenetic origin of petroleum, which admits that most commercial oils originated by thermal transformation of insoluble organic matter (kerogen) and water required for primary migration could he supplied by dehydration of expandable clays during burial of source sediments, has recieved much support from many workers. In this paper, a general review and the author's coments for the basic problems on this theory are presented. The important points among those are as follows. In the Japanese Tertiary oil fields, it seems that water released by such dehydration of expandable clays as suggested by Powers (1967) have not been effective for the primary migration of oil based on the depth-pattern investigation of clays and hydrocarbons. Accordingly the alternative explanation will be needed for the primary migration of the Japanese Tertiary oils. Commercial oils have not been found so much in areas consisting of oil shales principally, despite of the result that oil shales contain predominantly lipid-rich kerogen which has higher potential for oil generation by the advocators of “late diagenetic thory.” Although Powers (1967) has given only a simple explanation for this problem from the view of clay components of oil rhales, more thorough research on this problem will be required. At present, most of the studies favoured to “late diagenetic theory” are essentially carried out on the basis of “fossil” kerogen and the problems on transformation mechanism and process of “young” to “fossil” kerogen are left unsolved. However, for the formation of commercial oils, hydrocarbons generated during transformation of “young” to “fossil” kerogen seem to be much more important based on various geological and geochemical data. Further study on this problem is required.

Time of Hydrocarbon Expulsion, Paradox for Geologists and Geochemists

The time of inception and duration of oil expulsion from source rocks and its accumulation in trapped reservoirs remains a controversial problem. Many geochemists advocate that oil is expelled from source rocks only when crude oil-like hydrocarbons are formed in source rocks through the heat and pressure imposed by deep burial. Conversely, many experienced petroleum geologists point out that empirical data on the habitat of oil accumulations call for early, short-lived expulsion of hydrocarbons shortly after the burial of source and reservoir sediments. Because structural and stratigraphic complexities in the subsurface generally prohibit unequivocal interpretation of origin and movement of hydrocarbons from source to reservoir, it is suggested that special attention be given to unfaulted lenticular traps which limit alternative interpretations to the minimum. In a lenticular trap, geologic circumstances permit designation of enclosing pelitic sediments as source rock, and this allows the calibration of bona fide source-rock characteristics. Lenticular traps which never have been buried deeply and possess no avenues for long-distance migration demonstrate that hydrocarbons can be expelled and matured without the heat and pressure that geochemists advocate. Maturation of hydrocarbons takes place with time and depth of burial in source rocks and entrapped accumulations alike. These circumstances do not necessitate late expulsion and can be satisfied by advocating early expulsion of proto-oil, which then takes the same maturation path in a reservoir as that which it follows in the source rock; the point of separation is early, and the catalytic effects on proto-oil in the reservoir then run parallel with those on oil remaining in the source rock, later expulsions being prevented by drastic losses in permeability through lithification, compaction, and diagenesis. Late expulsion of hydrocarbons during the prolonged catagenic sequence in source rocks is believed by absence of accumulations in late traps, and because deep accumulations which should have benefitted from a longer expulsion sequence than shallower traps do not in fact provide supporting volumetric evidence. Resolution of the time-of-expulsion controversy becomes increasingly important because of the role which advocation of late or early migration plays upon exploration-prospect assessment. As hydrocarbons become ever more difficult to discover, every effort must be made to sharpen the explorationist's analytic tools, not least by reducing uncertainties regarding basic petroleum-geologic problems.

Influence of Nature and Diagenesis of Organic Matter in Formation of Petroleum

Elevation of temperature and pressure during burial of sediments results in a physiochemical transformation of the kerogen, and particularly in changes of elementary composition, infrared spectra, and thermal properties of kerogen. The combined variation of these characters defines an evolution path for each kerogen type (organic matter from similar environments of deposition group along the same evolution path). The degree of evolution of individual samples can be evaluated by using these techniques. An experimental evolution test, using thermogravimetric, infrared, and associated techniques, can reproduce the natural degradation of kerogen during its burial in a sedimentary basin. The test allows the petroleum geologist to make an evaluation of the petroleum potential of a given formation in the buried parts of a sedimentary basin, by using shallow or surface samples and simulating their degradation in the laboratory. The major products generated during the three successive steps of kerogen evolution are carbon dioxide and water; oil; gas. The relative abundance of these products depends on the composition of the original kerogen. Kerogen from a high evolution path generates abundant oil, whereas that from a low evolution path produces methane at depth, but little or no oil.

Magnetic smooth zones in the World's oceans

The distribution and geologic environment of magnetic smooth zones in the world's oceans are examined in order to determine their possible origins. The smooth zones are divided into two categories: (1) marginal smooth zones associated with the sedimentary deposits of continental rises, and (2) abyssal smooth zones located far from the continental margins in the deep sea. Abyssal smooth zones appear to result from two uniform polarity intervals, one in the Cretaceous and the second in the Jurassic, combined with some process, such as a fast spreading rate or crustal subsidence, that eliminates topographic anomalies. Many marginal smooth zones having ages coincident with the polarity intervals might have the same origins as abyssal smooth zones. However, marginal smooth zones are found almost solely on rifted continental margins, thus suggesting that they may owe their origin in part to the breakup of Pangea. As an alternate origin for marginal zones not having ages coincident with polarity intervals or as an additional process for those that do, we suggest that they are formed during the initial rifting of continents. Spreading rates are at first slow, producing narrow magnetic bodies. When these narrower bodies subside to continental margin depth, their anomalous magnetic field is attenuated at the sea surface. Marginal smooth zones might result from either or both processes, but all are accompanied by basement subsidence and deep sedimentary burial. Until the actual time spans (maximum and minimum ages) for certain marginal zones are known, sea floor spreading magnetic models cannot meaningfully be applied to test the various proposed origins.

Application of Plate Tectonics to Petroleum Exploration at Continental Margins: ABSTRACT

Approximately 90% of known reserves of oil and gas has accumulated within the past 250 million years, concurrent with formation of the present ocean basins, island ridges, and linear mountain chains of Andean and Alpine types. Concepts of crustal rifting, sea-floor End_Page 1844------------------------------ spreading, and plate tectonics help explain these tectonic features of the earth and may help locate additional reserves of petroleum, particularly along the present continental margins. Differential extension of the lithosphere may result in high temperatures in the upper continental crust concurrent with local accumulations of shallow-water sands, carbonate rocks, euxinic muds, evaporites, and volcanic rocks. Where the lithosphere rifts apart, seawater encroaches and the asthenosphere wells up in the formation of oceanic crust. During continued divergence of the continents, this new crust subsides as it cools and moves away from the rifts, downwarping with it the thinned edges of rifted continental crust. Remnants of tear faults on the rifted continental blocks, and the presence of volcanic rocks and salt diapirs may be clues to petroleum provinces buried beneath the detrital continental rises and/or carbonate platforms that characterize such divergent margins. Convergence of crustal plate margins (marked by oceanic trenches, linear trends of deep focus earthquakes, volcanic island ridges, and linear mountain chains) results in dominance of detrital over carbonate sedimentation, abrupt facies changes, locally rapid burial of deep water pelagic sediment with thick turbidites, shale diapirs, and layered sediment structures related to drape over differentially uplifted basement blocks, all on the trench side of volcanic island ridges and linear mountains. High temperature may accelerate the generation of petroleum on the continent side of such island ridges and mountains. Strike-slip displacements between adjacent crustal plates, combined with rifting or convergence, may explain other patterns of sedimentation, structure, and geothermal trends elated to accumulations of oil and gas. End_of_Article - Last_Page 1845------------

Influence of Nature and Diagenesis of Organic Matter in Formation of Petroleum: ABSTRACT

Marine or lacustrine sediments may be considered as subaquatic soils, in which organic matter is destroyed, transformed, or preserved to a certain extent, according to the conditions of sedimentation. Small amounts of hydrocarbons can be found, inherited from living organisms, either directly (like certain n-alkanes of high molecular weight) or through an early transformation (like steroid and triterpenoid types). When humic material is present in muds, it may represent a large amount of total organic matter and constitute the support of various functional types of compounds. The whole is able to evolve by loss of functional groups towards several types of kerogen, according to depositional environment. Elevation of temperature and pressure during burial of sediments results in a physicochemical transformation of the various kerogen types, along different evolutionary paths. The products formed include oil, gas, and other compounds like water and carbon dioxide. Nature and abundance of these products depend on particular evolutionary path and grade of diagenesis. The bulk of oil is formed at that stage of diagenesis in petroleum source rocks: the greatest rate of oil generation can be identified on the evolutionary paths, and is followed by gas generation as burial increases. Other types of organic matter produce little petroleum, but produce methane at great depth. Identification of the nature of kerogens resulting from depositional environment and of the grade of diagenesis resulting from the burial history allows the evaluation of the petroleum potential of a given formation. End_of_Article - Last_Page 809------------

Influence of Deep Sea Drilling Project on Concepts of Global Tectonics: ABSTRACT

The concept of sea-floor spreading has been examined in the Atlantic and Pacific oceans by paleontologic dating of the sediments that lie in contact with acoustic basement. Despite errors that could be introduced by burial of sediments by sills, paleontologic dating limitations, and deep-sea currents creating a hiatus at the basement-sediment contact, there is an extraordinarily good relation between age of the basal sediments and distance from the ridge crest. Based on these data, an average Cenozoic spreading rate in the north Atlantic is 1.2 cm/yr, in the south Atlantic 2.0 cm/yr, and in the equatorial Pacific 12 cm/yr. By extrapolating spreading rates Heirtzler et al. proposed an age scale for the identifiable magnetic anomalies that typify a spreading sea floor. The ges of the basal sediments recovered by drilling agree very well with the time scale to about 45 m.y. ago. From 45 to 70 m.y. ago the agreement is also good, but the age of the basal sediment appears consistently lower than the proposed time scale. The sediments indicate there may be significant mineralization associated with the basal sediments. Samples should make possible reconstruction of oceanic circulations of the past and the dependence of these circulations on arrangement and emergence above sea level of land masses. Migration of the crust relative to effects related to the rotational poles of the earth, such as the equatorial zone, can be deduced. End_of_Article - Last_Page 357------------

Origin and Evolution of Hydrocarbons in Early Toarcian Shales, Paris Basin, France

The purpose of the study was to investigate the conditions of formation and evolution of hydrocarbons during burial and related diagenesis of sediments. Early Toarcian shales (Early Jurassic), in the Paris basin, were selected because all parameters except temperature and pressure (both related to burial of sediments) remain constant--age, nature of fossil organisms and clay minerals, and conditions of deposition (which were fairly homogeneous in the formation across the surveyed area). The amounts of the different organic constituents and some structural properties of the molecules reveal an orderly variation, depending on maximum depth of burial. At the beginning of burial, the transformation ratio of organic matter to hydrocarbons is low and changes little to a depth of 1,500 m, where the ratio increases markedly with increased depth. A detailed study shows that hydrocarbons present at shallow depth are directly inherited from original living matter or result from early transformation in sediment, without changing the general structure of the molecule (like molecules of steroid and triterpenoid types). When burial becomes sufficiently deep, these characteristic structures are diluted among newly formed hydrocarbons generated by thermal degradation of organic matter. Interpretation of the observations leads to the conclusion that burial (i.e., increase of pressure and especially of temperature) constitutes the determining factor in the evolution of organic matter. The temperature rise promotes the formation of petroleum compounds, particularly hydrocarbons, at the expense of kerogen. A general reaction scheme is proposed, based on hypothesis on the structure of kerogen, and on the observed relations of the various organic compounds.

Order of Mixed-Layering in Illite/Montmorillonites

AbstractA number of otherwise poorly understood compositional-structural relationships in mixed-layer illite/montmorillonites appear to be explained by ordered interlayering of 2:1 units. The ordering appears to be between high and low charge 2:1 units. The relationship between per cent expandable layers and mean lattice charge in natural materials shows a scatter that is nicely bracketed by hypothetical curves constructed assuming random or completely ordered interlayering for several types of 2:1 charge distribution. Natural samples with 30–50% expandable layers plotting near the “ordered” curves have diffraction peaks at 25 Å for two water layers in the expandable layers and 27 Å with two glycol layers; samples plotting near the “random” curves do not have these peaks and have poorly developed 001/001 reflections.Some tentative conclusions are: (1) illites are virtually non-expandable at lattice charges significantly less than that of ideal mica because of ordering of high-low charge 2:1 units, (2) illites and mixed-layer illite/montmorillonites with the same mean lattice charge show a range of expandability because of varying degrees of ordering, (3) the highly variable CEC of samples with the same expandability also results from a varying degree of ordering.An interesting petrological implication results when it is realized that a sample with a given bulk composition can have a wide range of expandability, depending on ordering. Low expandability, achieved by ordering, should be promoted by formation at high pressures. Glauconites, known to form largely at the time of sedimentation, appear to be dominantly randomly interstratified; illites and illite/montmorillonites, which may form on deep burial of argillaceous sediments, are dominantly ordered.

Diagenesis in Clay Minerals—A Review

AbstractDiagenesis refers to the process, and the changes (usually excluding cation exchange) that take place in sediments after deposition, but definitions of the process vary widely over which changes, and what part (or all) of the time between the transportation of the sediment and the time that the sediment(ary rock) is studied, should be included in diagenesis. Furthermore, Weaver, Griffin, and others, have favored alternative explanations to account for many clay mineral distributions that previously have been interpreted as representing changes in clay minerals in both recent and ancient sediments, and which were referred to diagenesis.Although agreeing that such alternative explanations account best for many distributions of clay minerals, additional evidence that presumably is convincing of diagenesis is presented herein to account for the formation of certain other occurrences of glauconitic mica, glauconite, illite, corrensite, kaolinite, and vanadiferous micaceous clay. A two-stage mechanism is proposed for a possible process by which illite and probably corrensite are formed: (1) cation sorption driven by energy (activities) of the ions in solution, and binding energy of the clay minerals, and (2) subsequent rearrangement of ions in the clay mineral to produce illite. It is finally proposed that diagenesis of clay minerals is characterized by the addition to and incorporation into them of Me ions, such as Mg, K, Ca, Na, Al, Fe, V, SiO2, and others, driven mainly by chemical energy and aided by mechanical and thermal energy, but as the latter two become more effective the process is designated metamorphism (anamorphism).Long-time, diagenetic reactions after burial of sediments are probably less important, volume-wise, than provenance and terrestrial weathering in determining the mineralogy of argillaceous sedimentary rocks in the geologic column.