“Stalactites extérieures” dans les karsts tropicaux humides. Dépôts stalagmitiques de tufs calcaires, 2004, Taborosi Danko, Hirakawa Kazuomi

“Outside Stalactites” in humid tropical karst – Stalactitic deposits of calcareous tufa - Friable and porous stalactitic deposits composed of calcareous tufa – rather than sparry calcite characteristic of normal cave stalactites – are often encountered in the entrances of caves and plastered to cliffs in the humid tropics. Tufaceous stalactitic outside deposits are frequently mentioned in literature but are typically dismissed in a few sentences, even in review articles dedicated to calcareous tufa. Mostly based on fieldwork in the Mariana Island, we have identified a variety of depositional settings where stalactitic tufa occurs. These settings can be grouped into spelean, transitional, epigean, and littoral realms. Centimetre to tens of meters in scale, their overall shapes can be quite irregular, with crooked, bulbous, pendant-like, light-oriented and other deflected forms exceedingly common. The outside surfaces of these “stalactites” invariably lack the crystalline luster of cave speleothems and feel wet and pasty, or powdery and earthy when dry. They are often covered with organic coatings. Stalactitic tufas are generally lightweight, porous, and friable, and many small specimens are weak enough to be plucked by hand. Composed of layered microcrystalline material, sometimes reminiscent of chalk, these “stalactites” exhibit a bewildering variety of fabrics, which can be classified as encrusted, amorphous, and laminated. In addition, they contain much organic material, microbial structures, and detrital grains. A wide array of biota is associated with these features, and they are thought to form by biogenic mechanisms superimposed on abiotic physico-chemical precipitation from karst water. Biologic processes involved in the formation of stalactitic tufa are numerous and appear to involve hundreds of species. While it is now clear that stalactitic tufas are a result of abiotic and biogenic deposition, an additional possibility remains to be considered. It is not improbable that tufa-like stalactites could form by decay and diagenesis of true cave speleothems, if the latter are exposed at the land surface conditions. Stalactitic tufas represent a unique, subaerial variety of calcareous tufa rarely deliberated in karst literature.

Quaternary dedolomitization along fracture systems in a Late Triassic dolomitized platform (western Southern Alps, Italy), 2004, Ronchi P. , Jadoul F. , Savino R. ,

The studied area belongs to a south vergent thrust and fold belt of the Southern Alps of central Lombardy where the norian Dolomia Principale crops out. This up to 2 km thick carbonate platform succession has been massively dolomitized from early to shallow burial diagenesis. Dark grey bedded dolostones (basal Dolomia Principale), outcropping along the both lower slopes of Iseo Lake (lower Camonica Valley), show a complex network of dedolomitized white-grey areas. The calcareous lenses show an irregular, elongated (up to few ineters large) shape; they are usually located along fault-fracture systems and extending along the strata bedding. Two main fabrics have been recognized: the fabric A is formed by a reticulate of small fractures filled by calcite and surrounded by fine grained calcitized halos, the fabric B is associated to more intense fracturation process that locally gave rise to breccia fabric; moreover a ochre-reddish internal sediment is locally present in small cavities or as a breccia matrix, a huge speleothem-like cementation is associated to these dedolomitized fabric. This study was aimed to reconstruct the dedolomitization process and to propose a relevant genetic model. The petrographic analyses, integrated using cathodoluminescence and electron scanning microscope allowed to find out that dedolomitization process is composed of a first phase of dolomite dissolution along permeable path ways, both at the macro and at the micro scale, followed by calcite precipitation in the pore spaces. The negative delta(13)O and delta(13)C values of the calcite cements and the calcitic fraction of the dedolomitized fabrics suggest precipitation in presence of meteoric water derived fluids. Radiometric absolute age determination (U-230/Th-234) indicates that calcite cements precipitated in the last 100000 years: age during which the area was subject to several advances and retreats of glacial tongues. The field mapping, analytical data and the geomorphology of the areas where the dedolomitized patches are more frequent, in correspondence of a narrow passage of the lower Camonica valley, allowed us to infer that the dedolomitization developed during glacial-interglacial phases particularly active in the region during the Pleistocene. In particular we propose that the fracturation and the first phase of dedolomitization (fabric A) occurred during the glacial period, while extensive calcite precipitation and brecciation (fabric B) formed during the interglacial periods, dominated by a warm climate during which extensive soil cover and karst processes developed

Origin of Meter-Scale Submarine Cavities and Herringbone Calcite Cement in a Cambrian Microbial Reef, Ledger Formation (U.S.A.), 2004, De Wet Cb, Frey Hm, Gaswirth Sb, Mora Ci, Rahnis M, Bruno Cr,

Meter-scale submarine cavities in Middle Cambrian shelf-margin microbial reef strata indicate large-scale dewatering processes, in conjunction with substrate instability related to interreef channeling and shelf-edge downslope creep and slip. Syndepositional cement precipitation within the cavities preserved delicate microbial fabrics and stabilized the reef system. Radiaxial fibrous calcite and herringbone calcite cements line the cavity interiors isopachously. The two phases cannot be discriminated on the basis of Fe, Mn, or Sr contents, but do have different isotopic signatures. Slightly more negative {delta}13C values in herringbone calcite suggest that abrupt transitions between radiaxial fibrous and herringbone calcite cement are the result of rapid and repeated changes in pore-fluid oxygen levels. Storm-driven pore-water circulation renewed oxygenated seawater flow into the cavities, resulting in precipitation of radiaxial fibrous calcite. A threshold level of oxygen reduction resulted in the change to herringbone calcite precipitation. The pore fluids associated with herringbone calcite did not have elevated Mn or Fe concentrations, as suggested in previous studies. Herringbone calcite appears to be more susceptible to diagenetic alteration than radiaxial fibrous cement however, as indicated by greater resetting of oxygen isotope values

Les stalagmites du réseau du trou Noir (Gironde) : rôle de l’effet de site dans l’enregistrement du signal climatique et environnemental, 2006, Lans Benjamin , Maire Richard , Ortega Richard , Deves Guillaume , Bacquart Thomas , Plaisir Cyril , Quinif Yves Et Perrette Y.

The speleothems of trou Noir cave (Gironde, France): the role of their situation in registering climatic signals - The trou Noir is an active cave system (sinkhole-resurgence) situated in the Oligocene porous limestone of the plateau of Entre-deux-Mers near Bordeaux (Gironde). Six stalagmites have been sampled for analyzing the environmental evolution controlled by local parameters inside the cave. The studied indicators are calcitic microfabrics, lamination, discontinuities, porosity, organic matter, and radioactivity. Because of a narrow passage located in the middle of the cave, three speleothems upstream have recorded the fluctuations of the underground river during floods, especially detritic sedimentation (clay/calcite alternations), erosion (internal corrosion surface), mechanical shocks (fissures). Downstream, the three other stalagmites have not been flooded; in the small dry passage near the resurgence, two speleothems show, in thin section, many biologic filaments (bacteria or mycelian filaments) because of organic matter (guano from bats). The site is protected (Natura 2000). The trou Noir is an example of a young cave which has recorded the Holocene evolution, particularly the Little Ice Age (detrital/calcitic stalagmite) and the present period.

Paleokarst in Middle Devonian Winnipegosis mud mounds, subsurface of south-central Saskatchewan, Canada, 2006, Fu Q, Qing H, Bergman Km,

Paleokarst of the Winnipegosis mud mounds is mainly characterized by extensive solution features and cavity deposits. Solution features vary from millimetre-size vugs/channels to metre-scale caverns. Most solution voids are filled with anhydrite and/or carbonate deposits. 'Swiss-cheese' type porosities appear as oval to irregular pore networks and most of them remain open. Erosional surfaces are observed in several cores. Fractures and breccia fragments are small-scale and commonly associated with solution features or calcretes. Cavity sediments are dominantly detrital dolomite, interpreted as a product of weathering of the host rocks. Speleothems occur in vugs and channels but are not abundant. Caverns and large vugs likely formed at or just below the water table in the phreatic zone or in a freshwater-saltwater mixing zone during subaerial exposure of the mounds. Porous 'Swiss-cheese' fabrics resemble sponge-like pores that form in mixing zones of modern carbonate platforms and islands. Porosity in the Winnipegosis mounds was extensively modified by karstification and subsequent anhydrite cementation. Paleokarst occurs only in the middle and upper parts of relatively high Winnipegosis mounds with respect to the basin floor. Multiple levels of caverns and vugs are probably related to various positions of freshwater lenses corresponding to recurrent subaerial exposure and water level changes in the Elk Point Basin. Occurrence of caverns and large vugs at 55 m below the top of the mounds indicates that the mixing zone or freshwater has extended downward to this depth

Structurally controlled hydrothermal dolomite reservoir facies: An overview, 2006, Davies G. R. , Smith Jr. L. B.

Structurally controlled hydrothermal dolomite (HTD) reservoir facies and associated productive leached limestones are major hydrocarbon producers in North America and are receiving increased exploration attention globally. They include multiple trends in the Ordovician (locally, Silurian and Devonian) of the Michigan, Appalachian, and other basins of eastern Canada and the United States, and in the Devonian and Mississippian of the Western Canada sedimentary basin. They also occur in Jurassic hosts along rifted Atlantic margins, in the Jurassic–Cretaceous of the Arabian Gulf region and elsewhere. Hydrothermal dolomitization is defined as dolomitization occurring under burial conditions, commonly at shallow depths, by fluids (typically very saline) with temperature and pressure (T and P) higher than the ambient T and P of the host formation. The latter commonly is limestone. Proof of a hydrothermal origin for HTD reservoir facies requires integration of burial-thermal history plots, fluidinclusion temperature data, and constraints on timing of emplacement. Hydrothermal dolomite reservoir facies are part of a spectrum of hydrothermal mineral deposits that include sedimentary-exhalative lead-zinc ore bodies and HTD-hostedMississippi Valley–type sulfide deposits. All three hydrothermal deposits show a strong structural control by extensional and/or strike-slip (wrench) faults, with fluid flowtypically focused at transtensional and dilational structural sites and in the hanging wall. Transtensional sags above negative flower structures on wrench faults are favored drilling sites for HTD reservoir facies. Saddle dolomite in both replacive and void-fillingmodes is characteristic of HTD facies. For many reservoirs, matrix-replacive dolomite and saddle dolomite appear to have formed near-contemporaneously and from the same fluid and temperature conditions. The original host facies exerts a major influence on the lateral extent of dolomitization, resultant textures, pore type, and pore volume. Breccias zebra fabrics, shear microfractures, and other rock characteristics record short-term shear stress and pore-fluid-pressure transients, particularly proximal to active faults. High-temperature hydrothermal pulses may alter kerogen in host limestones, a process designated ‘‘forced maturation.’’ basement highs, underlying sandstone (and/ or carbonate?) aquifers (probably overpressured), and overlying and internal shale seals and aquitards also may constrain or influence HTD emplacement. Although many questions and uncertainties remain, particularly in terms of Mg and brine source and mass balance, recognition and active exploration of the HTD play continues to expand. Increasing use of three-dimensional seismic imagery and seismic anomaly mapping, combined with horizontal drilling oblique to linear trends defined by structural sags, helps to reduce risk 

Fractured hydrothermal dolomite reservoirs in the Devonian Dundee Formation of the central Michigan Basin, 2006, Luczaj J. A. , Harrison Iii. W. B. , Williams N. S.

The Middle Devonian Dundee Formation is the most prolific oilproducing unit in the Michigan Basin, with more than 375 million bbl of oil produced to date. Reservoir types in the Dundee Formation can be fracture controlled or facies controlled, and each type may have been diagenetically modified. Although fracture-controlled reservoirs produce more oil than facies-controlled reservoirs, little is known about the process by which they were formed and diagenetically modified. In parts of the Dundee, preexisting sedimentary fabrics have been strongly overprinted by medium- to coarse-grained dolomite. Dolomitized intervals contain planar and saddle dolomite, with minor calcite, anhydrite, pyrite, and uncommon fluorite. Fluid inclusion analyses of two-phase aqueous inclusions in dolomite and calcite suggest that some water-rock interaction in these rocks occurred at temperatures as high as 120–150jC in the presence of dense Na-Ca-Mg-Cl brines. These data, in conjunction with published organic maturity data and burial reconstructions, are not easily explained by a long-term burial model and have important implications for the thermal history of the Michigan Basin. The data are best explained by a model involving short-duration transport of fluids and heat from deeper parts of the basin along major fault and fracture zones connected to structures in the Precambrian basement. These data give new insight into the hydrothermal processes responsible for the formation of these reservoirs. 

Burial dolomitization and dissolution of Upper Jurassic Abenaki platform carbonates, Deep Panuke reservoir, Nova Scotia, Canada, 2006, Wierzbicki R. , Dravis J. J. , Alaasm I. , Harland N.

A large gas reservoir was discovered in the previously unproductive Jurassic-aged Abenaki carbonate margin in 1998. Most of the reservoir porosity is developed in dolostones. These dolostones replaced preexisting wackestones, packstones, and grainstones(?) associated with reefal and adjacent depositional environments. Many dolomites were subsequently recrystallized or dissolved, accounting for much of the preserved secondary porosity. Subsequent fracturing helped enhance reservoir permeabilities. Enhanced petrographic techniques established that dissolution of previously dolomitized fabrics generated much of the secondary porosity in these dolostones. Diffused plane-polarized light revealed relict grains and textures invisible with standard microscopic observations. Petrographic and geochemical observations also confirmed that dissolution occurred under deep-burial conditions after incipient pressure solution. Dissolutionwas not confined to the centers of dolomitized grains, as is commonly seen when remnant calcitic grains dissolve out during the advanced stages of replacement dolomitization. Instead, dissolution was random within relict grains, as isolated dolomite crystals were also variably dissolved. The geochemistry of these dolomites and associated late-stage calcites implied precipitation from basinal hot fluids, as well as hydrothermal fluids. Later diagenetic fluids, either acidic or calcium rich, or perhaps both at different times (based on associated mineralization), seemingly promoted dolomite dissolution. The presence of tectonic fractures and stylolites, helium gas, and faults observed in seismic data implied that dolomitization and subsequent dissolution along the Abenaki platform margin were controlled by reactivated wrench faults tied to basement. On a finer scale, diagenetic fluids moved through fractures and pressuresolution seams. The data collected to date support our contention that the dolomitization and dissolution process, which has created most of the porosity in the Abenaki reservoir, was poststylotization and deeper burial in origin. Given the timing of tectonic activity in the area and its inferred connection to diagenesis, it is probable that at least a part of the diagenetic fluids were hydrothermal in nature 

Intérêt de l’analyse pétrographique des spéléothèmes pour les reconstitutions paléoenvironnementales, 2007, Couchoud I.

The significance of speleothem petrography in paleoenvironmental reconstruction - Speleothem petrography, like oxygen and carbon isotopic ratios, is influenced by various hydrological, chemical, biological and physical factors at the time of growth. While speleothem-based paleoenvironmental studies using stable isotope records are increasingly numerous, interpretations remain problematic. This paper aims to highlight the significance of a petrographical approach to the study of speleothems as a complement to isotopic studies. First, a synthesis of the main calcite crystalline fabrics encountered in speleothems is presented and a terminology suggested. A summary of the current state of knowledge about the relationships between fabrics and (i) the conditions of speleothem precipitation and (ii) speleothem carbon and oxygen isotopic ratios is then provided. It appears that some fabrics are essentially controlled by two main parameters: i) the chemical efficiency of the solution; and 2) the drip rate and variability. As a function of the respective importance of these two parameters, fabrics evolve within a continuum from elongated columnar fabric (typically, high intensity and low variability - low chemical efficiency) to dendritic fabric (low intensity and high variability - high chemical efficiency) via two intermediate forms, compact and open columnar fabrics.Other fabrics are associated with specific conditions of precipitation. For example, a high concentration of impurities in the source water can produce a microcrystalline fabric; precipitation in a tunnel environment can give rise to squat columnar fabric; and recrystallisation can produce a mosaic fabric. Combined with known conditions of precipitation, fabrics can be used to evaluate the quality of the stable isotope signals recorded by speleothems and can help in the interpretation of paleoenvironmental records.

HYPOGENE KARST AND SULFATE DIAGENESIS OF THE DELAWARE BASIN: SOUTHEASTERN NEW MEXICO AND FAR WEST TEXAS, PhD Thesis , 2008, Stafford, Kevin Wayne

Hypogene speleogenesis is widespread throughout the Delaware Basin region as evidenced by intrastratal dissolution, hypogenic caves and suites of diagenetic minerals. The world famous carbonate caves of the Capitan reef facies of the Guadalupe Mountains have long been associated with sulfuric acid processes and recently have been associated with semi-confined, hypogene dissolution. However, evaporite karst within Permian backreef and basin-filling facies has been traditionally associated with surficial, epigene processes. On the eastern edge of the Delaware Basin cavernous porosity associated with oil reservoirs in Permian carbonates have been attributed to eogenetic karst processes.
Interbedded (evaporite / carbonate), backreef facies within the mid-Permian Seven Rivers Formation exhibit characteristics of hypogene karst associated with semi-confined dissolution controlled by the eastward migration and entrenchment of the Pecos River. Coffee Cave is a good example of hypogene dissolution, forming a multi-storey, rectilinear maze with abundant distinctive morphologic feature suites (i.e. risers, channels and cupolas) indicative of hypogene speleogenesis. Other caves within the Seven Rivers and Rustler Formations show similar patterns, although often less well developed.
Within the Delaware Basin, Castile Formation evaporites have been extensively modified by hypogene processes. Field mapping coupled with GIS analyses clearly shows that karst development and evaporite calcitization are highly clustered throughout the outcrop area. Individual caves commonly exhibit complex morphologies, including complete suites of morphologic features indicative of intrastratal dissolution. Clusters of hypogene caves are commonly associated with clusters of evaporite calcitization and often occurrences of secondary selenite bodies, suggesting all three are genetically related. Brecciated cores and associated native sulfur deposits indicate that calcitized evaporites are the result of semi-confined sulfate reduction in the presence of ascending hydrocarbons. Hypogene caves are currently being overprinted by epigene processes as surface denudation results in breaching of previously confined solutional conduits. However, calcitized evaporites stand as resistant masses attesting to the widespread importance of hypogene processes within the Castile Formation.
On the southern end of the Central Basin Platform, the spatial distribution of cavernous porosity, secondary mineralization and abundant karst fabrics within the Yates Field carbonate strata provide convincing evidence that karst porosity, at least locally, within the San Andres and overlying Permian strata is the result of hypogene speleogenesis. Porosity development appears to have been enhanced by high geothermal gradients and the addition of sulfuric acid-rich fluids, reminiscent of the same processes that have been proposed for the extensive carbonate caves of the Guadalupe Mountains.
Recognition of the widespread occurrence of hypogene speleogenesis throughout the Delaware Basin region indicates that the regional diagenetic evolution has been significantly affected by confined fluid migration, including not only the development of porosity but also the emplacement of many secondary mineral deposits. Therefore, future natural resource management plans must consider the nature of hypogene karst in site evaluations throughout the region in order to better predict geohazards, potential groundwater contamination and characterize mineral resources.

Microbial Communities and Associated Mineral Fabrics in Altamira Cave, Spain., 2009, Cuezva S. , Sanchezmoral S. , Saizjimenez C. And Cañaveras J. C.

Evidences of microbial colonizations were observed in Altamira Cave, Spain. These consisted of distinct small coloured colonies, both on walls and ceiling, mainly located in the area near the cave entrance, which progressed until reaching the Polychromes Hall. The colonizations were characterized by a high morphological and microstructural variability and related to biomineralization processes. Two main types of CaCO3 deposits were related to the colonies: rosette- or nest-like aggregates of rhombohedral calcite crystals, and spheroid to hemispheroid CaCO3 elements. Colonies distribution seems to be controlled by microenvironmental conditions inside the cavity. The areas of the cave showing higher temperature, relative humidity, and CO2 concentration fluctuations presented a minor biomineralization capability.

Microbial Communities and Associated Mineral Fabrics in Altamira Cave, Spain., 2009, Cuezva S. , Sanchezmoral S. , Saizjimenez C. , Cañaveras J. C.

Evidences of microbial colonizations were observed in Altamira Cave, Spain. These consisted of distinct small coloured colonies, both on walls and ceiling, mainly located in the area near the cave entrance, which progressed until reaching the Polychromes Hall. The colonizations were characterized by a high morphological and microstructural variability and related to biomineralization processes. Two main types of CaCO3 deposits were related to the colonies: rosette- or nest-like aggregates of rhombohedral calcite crystals, and spheroid to hemispheroid CaCO3 elements. Colonies distribution seems to be controlled by microenvironmental conditions inside the cavity. The areas of the cave showing higher temperature, relative humidity, and CO2 concentration fluctuations presented a minor biomineralization capability.

Holocene glacier history from alpine speleothems, Milchbach cave, Switzerland, 2011, Luetscher M. , Hoffmann D. L. , Frisia S. , Spö, Tl C.

Mountain glaciers and their sediments are prominent witnesses of climate change, responding sensitively to even small modifications in meteorological parameters. Even in such a classical and thoroughly studied area as the European Alps the record of Holocene glacier mass-balance is only incompletely known. Here we explore a novel and continuous archive of glacier fluctuations in a cave system adjacent to the Upper Grindelwald Glacier in the Swiss Alps. Milchbach cave became partly ice-free only recently and hosts Holocene speleothems. Four coeval stalagmites show consistent petrographic and stable isotopic changes between 9.2 and 2.0ka which can be tied to abrupt modifications in the cave environment as a result of the closing and opening of multiple cave entrances by the waxing and waning of the nearby glacier. During periods of Holocene glacier advances, columnar calcite fabric is characterized by 18O values of about 8.0 indicative of speleothem growth under quasi-equilibrium conditions, i.e. little affected by kinetic effect related to forced degassing or biological processes. In contrast, fabrics formed during periods of glacier minima are typical of bacterially mediated calcite precipitation within caves overlain by an alpine soil cover. Moreover, 18O values of the bacterially mediated calcite fabrics are consistent with a ventilated cave system fostering kinetic fractionation. These data suggest that glacier retreats occurred repeatedly before 5.8ka, and that the amplitudes of glacier retreats became substantially smaller afterwards. Our reconstruction of the Upper Grindelwald Glacier fluctuations agrees well with paleoglaciological studies from other sites in the Alps and provides a higher temporal resolution compared to traditional analyses of peat and wood remains found in glacier forefields.

Speleothem deposition at the glaciation threshold — An attempt to constrain the age and paleoenvironmental significance of a detrital-rich flowstone sequence from Entrische Kirche Cave (Austria), 2012, Meyer M. C. , Spötl Ch. , Mangini A. , Tessadri R.

Proxy records from high-altitude locations predating the Last Glacial Maximum are rare but could provide invaluable insights into the response of alpine catchments to the rapid climate fluctuations which characterized the last glacial period. Herewe present a detrital-rich flowstone record from Entrische Kirche Cave, an inneralpine cave situated close to the accumulation area of the Pleistocene ice-stream network of the European Alps that expanded repeatedly into the lowlands during glacial maxima. U–Th dating of this calcite is challenging due to high detrital Th. However, petrographic and stable isotope analyses in conjunction with associated clastic cave sediments provide useful insights into the climatic boundary conditions during speleothem formation and into the paleoenvironmental processes which operated in the ~2000 m-high catchment above the cave. Our data show that millennial-scale temperature fluctuations had a first-order control on the periglacial activity and vegetation in the catchmentwhich strongly influenced the formation and infiltration of detritus into the karst aquifer. The brown laminated and brown dendritic fabrics that compose much of the detrital-rich flowstone succession reflect these environmental processes. The temperature-dependence of periglacial and permafrost processes allows to constrain the amount of cooling relative to the present-day mean annual air temperature that is required to initiate detrital-rich calcite formation in Entrische Kirche Cave, i.e. −2.5 °C (minimum) to −6 °C (maximum), respectively. White inclusion-poor calcite that is intercalated with the detrital-rich calcite indicates warm (interstadial) conditions and geomorphological stability in the catchment area. One such phase has been U–Th dated to 88.3±6.9 ka (i.e. Greenland Interstadial 21 or 22). 

Carbonate Aquifers, 2012, Cunningham K. J. , Sukop M. C. , Curran H. A.

Only limited hydrogeological research has been conducted using ichnology in carbonate aquifer characterization. Regardless, important applications of ichnology to carbonate aquifer characterization include its use to distinguish and delineate depositional cycles, correlate mappable biogenically altered surfaces, identify zones of preferential groundwater flow and paleogroundwater flow, and better understand the origin of ichnofabric-related karst features. Three case studies, which include Pleistocene carbonate rocks of the Biscayne aquifer in southern Florida and Cretaceous carbonate strata of the Edwards–Trinity aquifer system in central Texas, demonstrate that (1) there can be a strong relation between ichnofabrics and groundwater flow in carbonate aquifers and (2) ichnology can offer a useful methodology for carbonate aquifer characterization. In these examples, zones of extremely permeable, ichnofabric-related macroporosity are mappable stratiform geobodies and as such can be represented in groundwater flow and transport simulations.