Taxonomic, anatomical, and spatio-temporal variations in the stable carbon and nitrogen isotopic compositions of plants from an African savanna

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios are commonly used to reconstruct palaeodiets and palaeoenvironments. The method is based on our knowledge of isotopic patterns in plants, which are subject to taxonomic and environmental variability. While previous researchers have addressed isotopic variability amongst plants, no studies have looked extensively at a broad suite of taxa over multiple temporal scales from within the savanna biome so as to provide baseline data for palaeodietary and palaeoenvironmental studies. Here we document variations in the isotopic compositions of plants collected over two years from the Kruger National Park, South Africa, with respect to species and anatomical differences, and the influences of geological substrate and spatio-temporal shifts in climate. Results show that environmentally-induced carbon isotopic variations in plants within this region are generally smaller than 2‰, which is lower than what has been previously reported for plants compared across multiple habitat-types. These data suggest that δ¹³C differences of 2‰ or more (or 1‰ if the diet is predominantly C₄) between animals from a given area reliably indicate real dietary differences. Plant δ¹⁵N values vary greatly between different microhabitats (by up to 4‰), responding to a range of environmental influences that may, in turn, significantly influence variation in animal δ¹⁵N values.     

C4‐Plant Foraging in Northern Italy: Stable Isotopes,Sr/Ca and Ba/Ca Data of Human Osteological Samples from Roccapelago (16th–18th Centuries AD)

Human osteological samples (n = 23) taken from different anatomical parts of 11 individuals from the early modern (16th–18th century AD) site of Roccapelago (Modena, Italy) were systematically analysed for δ¹³C, δ¹⁵N and trace elements to investigate their diet. δ¹³C and δ¹⁵N correlate and show a high variability between individuals, attesting to the dietary contribution of C₄ plants. This is supported by pollen analysis of the burial site samples, which revealed the presence of maize. δ¹⁵N correlates with Sr/Ca, suggesting that the main protein source could have been milk and dairy. We therefore interpret the strong correlation between δ¹³C and δ¹⁵N as evidence for C₄‐plant foraging practice and the exploitation of livestock for meat and milk, combined with possible direct intake of C₄ plants. The Roccapelago site represents an important case study to track the evolution of the post‐medieval diet and the introduction of maize cultivation in southern Europe, as also attested by historical sources.     

Late Stone Age subsistence in the Tilemsi Valley, Mali: Stable isotope analysis of human and animal remains from the site of Karkarichinkat Nord (KN05) and Karkarichinkat Sud (KS05)

The pathways leading to the adoption of cereal cultivation and pastoralism in West Africa are poorly understood. In order to elucidate the transition to food production during the Late Stone Age in Mali’s Tilemsi Valley samples of ancient and modern human and animal remains were selected for carbon and oxygen isotope analysis. Our results indicate the inhabitants of Karkarichinkat Nord (KN05) consumed considerable quantities (85%) of carbon derived from C₄ plants, either directly in the form of C₄ grasses such as wild Panicum sp. and possibly domestic Pennisetum sp. or indirectly through the consumption of C₄ grazers such as Bos sp. and Ovis sp.     

Molecular evidence of changing foodways across the Mississippian transition at the George Reeves site (11S650)

ABSTRACT

The George Reeves site (11S650) is a multicomponent village on the bluffs in the central American Bottom, Illinois. The site was occupied from the Late Woodland Rosewood phase through the Mississippian Lohmann phase. Pottery use and dietary variation between the Late Woodland and Emergent Mississippian occupations at the site were explored through stylistic analysis, pottery residue analysis, and compound-specific carbon isotopic analysis of pottery residues. Although more samples should be analyzed, diet and pottery use at George Reeves seems to have been varied, with maize present by cal AD 900–1000, but comprising a relatively small portion of lipid residues in pottery. Residue analysis indicates a C₄ presence in 5 of 16 sampled pots from the early Emergent Mississippian deriving from either maize or from meat from animals consuming maize. Pottery residues were mixed, showing C₃ and C₄ plants as well as meat and fish or shellfish. One residue showed a high incidence of C₄ contribution, most likely from Portulaca oleracea (common purslane), as well as large amounts of fish or shellfish and another C₃ plant. Residue from a ceramic pipestem indicates that maize may have been smoked, probably in the form of maize silk mixed with other nontobacco plants.     

REAPPRAISAL OF MAGNITUDE OF 20TH CENTURY EARTHQUAKES IN SWITZERLAND

We reappraise the material needed to assess the 20th-century seismicity of Switzerland and of the adjacent areas of the Alps in terms of magnitude. For this we make use of macroseismic reports and literature and by calculating the surface-wave magnitude from the Prague formula of all significant earthquakes in the region. No attempt is made to relocate earthquake positions; instead their reliability is ranked using existing solutions and macroseismic observations We find that for small earthquakes (M _s >4.5), which constitute the bulk of the events in the region, the calculation of M _s observed at relatively short distances, requires station and distance corrections which can be significant. Also we find that recomputed Ms estimates differ from those reported in other earthquake catalogues. From this reappraisal of M _s and from a uniform re-evaluation of the associated macroseismic data, we derive a stable correlations between M _s and felt areas that can be used to assess the magnitude of historical, pre-instrumental, events for which only isoseismal radii (r _i ) and the associated intensities (I _i ) are available. We examined the conversion of surface-wave magnitude into moment magnitude, a conversion that presents some interesting problems for relatively small events for which the M _s -log(Mo) scaling changes. We conclude that the rate of moment release derived from events of M _s >4.0 is small, and that it should be associated with horizontal and vertical velocity rates of less than 1 mm/yr, too small vo be confirmed by GPS measurements over short periods of time so that can be used to constrain hazard assessment.     

Patterns of Resource Use and Isotopic Niche Overlap Among Guanaco (Lama guanicoe), Pampas Deer (Ozotoceros bezoarticus) and Marsh Deer (Blastocerus dichotomus) in the Pampas. Ecological,Paleoenvironmental and Archaeological Implications

ABSTRACT

In this paper, we analyze the isotopic niche and resource use of the guanaco (Lama guanicoe), pampas deer (Ozotoceros bezoarticus) and marsh deer (Blastocerus dichotomus) on the temperate plain of the northern Pampa region in the southeast of South America. The measured stable isotope compositions in bone tissue are δ¹³C, δ¹⁵N and δ¹⁸O. All the analyzed samples were recovered from different archaeological sites from the late Holocene. According to the results, the guanaco was strictly confined to the Pampa plain environment, developing a broad niche based on C₃ plants and a variable contribution of C₄ grasses within a grazing trend. The pampas deer preferentially used the Pampa plain, but also the prairies on the borders of the wetland, showing eurioic characteristics and a narrower niche based on C₃ plants. In turn, the marsh deer was strictly confined to wetland environments, developing a C₃ diet–base, within a narrow isotopic niche and stenoic characteristics. The three mammals showed a wide range of intraspecific variability, which was a key factor in their adaptability to spatial and temporal changes in the vegetation coverage. In fact, the temporal trends of their isotopic values were concurrent with the major climatic variations of the Holocene. Differences in the correlations between the values of both carbon sources in both deer species compared with the guanaco suggest a distinct chemical composition of their diet and/or differences in the allocation of nutrients. The isotopic values of nitrogen and spacing of the carbon sources in guanaco (pseudoruminant) and both deer species (ruminants) show no significant differences between them, thus establishing the values for local large herbivores. Significant correlations between δ¹³C and δ¹⁵N were found in the guanaco and marsh deer. The regional and extra–regional variability in the guanaco's δ¹³C_collagen and δ¹⁵N probably reflect the clinal variations in the vegetation coverage and the amount of rainfall. The collagen isotope values in the guanaco throughout the entire Holocene show that the humid Pampa would have shifted between being a more recurrent mesic and temperate plain with minor phases of dry–mesic conditions like during the Little Ice Age, and a humid and warm one at the peaks of the Holocene Thermal Maximum and the Medieval Climatic Anomaly. The guanaco and the pampas deer adapted to all the climatic changes that happened on the humid Pampa until the biological invasions of large European mammals changed the herbivores’ guild composition of this vast plain, pushing them into peripheral habitats due to competition. The within–species variability in isotopic signals through time and space make it necessary to carry out adequate sampling before reconstructing the diets of local past populations.     

Transient fluid flow in and around a fault

We present the results of simple numerical experiments in which we study the evolution with time of fluid flow around and within a permeable fault embedded in a less permeable porous medium. Fluid movement is driven by an imposed vertical pressure gradient. The results show that fluid flow is controlled by two timescales: τ_f = Sl²/κ_F and τ_F = Sl²/κ_M, where S is the specific storage of the porous material, l the length of the fault, and κ_M and κ_F are the hydraulic conductivities of the porous material and the fault, respectively. Fluid flow and the associated fluid pressure field evolve through three temporal stages: an early phase [t < τ_f] during which the initial fluid pressure gradient within the fault is relaxed; a second transient stage [τ_f < t < τ_F] when fluid is rapidly expelled at one end of the fault and extracted from the surrounding rocks at the other end leading to a reduction in the pressure gradient in the intact rock; a third phase [t < τ_F] characterized by a steady‐state flow. From the numerical experiments we derive an expression for the steady‐state maximum fluid velocity in the fault and the values of the two timescales, τ_f and τ_F. A comparison indicates excellent agreement of our results with existing asymptotic solutions. For km‐scale faults, the model results suggest that steady‐state is unlikely to be reached over geological timescales. Thus, the current use of parameters such as the focusing ratio defined under the assumption of steady‐state conditions should be reconsidered.     

ROMAN AND MEDIEVAL GLASS FROM THE ITALIAN AREA: BULK CHARACTERIZATION AND RELATIONSHIPS WITH PRODUCTION TECHNOLOGIES*

Compositional investigations were performed on 81 Roman and medieval glass fragments (first to 14th centuries ad ) from four Italian archaeological sites. The samples were soda–lime–silica in composition, with natron as flux for the Roman and early medieval glass samples, and with plant ash as flux for the late medieval ones. The varying colours are due to the differing FeO, Fe ₂ O ₃ , MnO and Sb ₂ O ₃ contents. Hierarchical cluster analysis identified six compositional groups related to age, which were compared with those found in the literature. In this way, technological continuity from the Roman to the early medieval period and the appearance of plant ash technology in the ninth century, 200 years in advance of the period previously believed, are demonstrated.     

An Investigation of Characteristic Periods of Seismic Ground Motions

The design seismic base shear was obtained from the spectral elastic acceleration S_a divided by a system behavior factor R, accounting for ductility and overstrength. The behavior factor is currently taken as a constant for a given type of structures in various codes regardless of structural periods. In fact, the behavior factor is also a spectrum varying with the natural periods of structures. In order to understand the relationship between the spectral values and the corresponding characteristic periods in these two spectra, S_a and R_μ, this article carries out an investigation into the characteristic periods of 370 seismic ground motions from 4 site types. It is found that the periods T_ga at which the peak values appear in the S_a spectra are much less than the periods T _gR at which the R_μ spectra take a maximum value. Two characteristic periods are necessary to determine the seismic action if a more elaborate procedure is required in practice. Statistical study on these two periods is carried out for the 370 records, and results are presented. For site types A–D, the ratio of these two periods has a statistically averaged value of 5.5–6.7.

The maximum input energy S _EI , relative velocity S _v , power density P _SD , and the Fourier amplitude F _S spectra were constructed to determine their characteristic periods, respectively. These four spectra predict similar characteristic periods to T _gR . T _gR is very close to the characteristic period T _gd of the elastic displacement spectra.

Analysis of SDOF systems under combined harmonic excitations shows that the S_a spectrum is more sensitive to high-frequency excitations, while the displacement spectrum is more sensitive to long period excitations. For the elastic-plastic S_a spectra, peak values tend to appear at shorter periods even the amplitudes of the longer periods are greater than that of the shorter period. This provides an explanation on different characteristic periods in the S_a and R_μ spectra.     

Stable carbon and nitrogen isotope variations in tooth dentine serial sections from Wharram Percy

Here we report δ¹³C and δ¹⁵N measurements of serial sections of human deciduous and permanent tooth dentine from archaeological samples taken from the medieval village site of Wharram Percy, Yorkshire, UK. We found a pattern of enrichment, for both δ¹³C and δ¹⁵N, where the tooth crown was greater than the cervical part of the root, which in turn was greater than the apical portion of the root and the associated rib collagen values. This pattern reflects a decrease in the consumption of isotopically enriched breast milk and the introduction of less enriched weaning foods in the diet. The (mean±SD) difference between the deciduous second molar crowns and corresponding rib samples from the same individuals after 2 years of age was 1.2±0.4‰ for δ¹³C and 3.2±0.8‰ for δ¹⁵N. The δ¹⁵N values are as predicted, but as there were no C₄plants at Wharram Percy, this 1.2‰ enrichment in δ¹³C represents clear evidence of a carbon trophic level effect in collagen from breastfeeding infants. Carbon and nitrogen results also show that the infant diet among those who died in infancy did not differ from those who survived into childhood. This study demonstrates the promise of using dentine serial sections to study the temporal relationships of breastfeeding, weaning, and dietary patterns of single individuals.     

Foddering by Mongolian pastoralists is recorded in the stable carbon (δC) and nitrogen (δN) isotopes of caprine dentinal collagen

Direct identification of fodder provisioning in individual animals is a previously unexplored area that has important implications for determining animal husbandry strategies in prehistory. In this study, foddering practices are examined in modern domestic and wild caprines from Mongolia (Baga Gazar'in Chuluu) through carbon and nitrogen analyses of bulk sampled dentin collagen in molar teeth. Foddered caprines display significantly different δ¹³C values compared to non-provisioned caprines. This pattern reflects the consumption of C₄ plants year-round by provisioned caprines while non-provisioned caprines ingest C₄ plants only during the summer months. Provisioned caprines also display significantly different nitrogen isotopic values relative to non-provisioned animals. The difference in nitrogen isotopes between wild and foddered animals may be due to increased access in quality graze through foddering by domestic caprines, which results in improved nutrition and extended lactation periods, or enriched δ¹⁵N of fodder plants relative to background flora. Differences in tooth wear between sampled wild and foddered animals may also contribute to the observed δ¹⁵N differences.     

Quantitative analysis of COH fluids synthesized at HP–HT conditions: an optimized methodology to measure volatiles in experimental capsules

The quantitative assessment of COH fluids is crucial in modeling geological processes. The composition of fluids, and in particular their H₂O/CO₂ ratio, can influence the melting temperatures, the location of hydration or carbonation reactions, and the solute transport capability in several rock systems. In the scientific literature, COH fluids speciation has been generally assumed on the basis of thermodynamic calculations using equations of state of simple H₂O–nonpolar gas systems (e.g., H₂O–CO₂–CH₄). Only few authors dealt with the experimental determination of high‐pressure COH fluid species at different conditions, using diverse experimental and analytical approaches (e.g., piston cylinder + capsule piercing + gas chromatography/mass spectrometry; cold seal + silica glass capsules + Raman). In this contribution, we present a new methodology for the synthesis and the analysis of COH fluids in experimental capsules, which allows the quantitative determination of volatiles in the fluid by means of a capsule‐piercing device connected to a quadrupole mass spectrometer. COH fluids are synthesized starting from oxalic acid dihydrate at P = amb and T = 250°C in single capsules heated in a furnace, and at P = 1 GPa and T = 800°C using a piston‐cylinder apparatus and the double‐capsule technique to control the redox conditions employing the rhenium–rhenium oxide oxygen buffer. A quantitative analysis of H₂O, CO₂, CH₄, CO, H₂, O₂, and N₂ along with associated statistical errors is obtained by linear regression of the m/z data of the sample and of standard gas mixtures of known composition. The estimated uncertainties are typically <1% for H₂O and CO₂, and <5% for CO. Our results suggest that the COH fluid speciation is preserved during and after quench, as the experimental data closely mimic the thermodynamic model both in terms of bulk composition and fluid speciation.     

Petroleum type determination through homogenization temperature and vapour volume fraction measurements in fluid inclusions

Physical parameters of petroleum‐bearing fluid inclusions such as bulk density (ρ), molar volume (V_m), vapour volume fraction (?_vap) and homogenization temperature (T_h) are essential information to model petroleum composition (x) in inclusions and to reconstruct palaeotemperature and palaeopressure of trapping. For the main petroleum types contained in a fluid inclusion, we can follow how ?_vap and T_h are simultaneously influenced by a change of bulk density in a ?_vap versus T_h projection. We have correlated T_h and ?_vap for different petroleum compositions for a large range of bulk density values. However, postentrapment events under new pressure (P) and temperature (T) conditions can greatly modify the initial fingerprints of physical conditions and chemical composition of fluid inclusions. Re‐equilibration is frequent, especially in the case of fragile minerals. Stretching and leakage phenomenon have been simulated using the Petroleum Inclusion Thermodynamics (pit ) software, from virtual petroleum inclusions with known hydrocarbon composition. The aim of these simulations is to understand how ?_vap and T_h evolve with these re‐equilibration phenomena, with respect to the oil composition. Results of stretching simulations show a characteristic increase of T_h and ?_vap along correlation curves, with the curve shape dependent on petroleum composition. Leakage simulations show an increase of T_h and a smaller increase or even a decrease in ?_vap. Consequently, the better preserved inclusions in a given population can be presumed to be those that have the lowest T_h. Applications of T_h and ?_vap measurements of natural inclusions in calcite and in quartz showed that the fragility of the host mineral is a key factor allowing the recording of post‐entrapment events. Inclusions that have stretched or leaked are identified and the best preserved inclusions selected for evaluation of P–T–x trapping conditions. Moreover, petroleum types trapped in inclusions can be identified from ?_vap and T_h measurements without compositional modelling.     

Thermodynamic modeling of petroleum inclusions: the prediction of the saturation pressure of crude oils

Microthermometry and volumetric analysis are now widely used techniques in petroleum geology, which allow the reconstitution of the composition and P‐T trapping conditions of petroleum inclusions. However, these methods require efficient thermodynamic modeling tools of the PVT properties, coupled with compositional models for petroleum. Two methods presently available are reviewed here. The first one, called the α–β method, uses a compositional model describing the full spectrum (C₁–C₅₀₀) of natural hydrocarbons with two adjustable parameters α and β. The second technique is based on a so‐called fluid model, i.e., a priori knowledge of the composition and the physical properties of the C₇₊ cut of the trapped petroleum. Up to now, no critical appraisal has been undertaken for these two methods. From an extensive compilation of literature data (201 points), we here show that both techniques are able to describe the composition of crude oils and to predict satisfactorily their saturation pressures. However, the predictive capabilities of fluid models are highly dependent on the correlations used for describing heavy cuts, and we indicate those which give the best results. Finally, we emphasize the key control of the bulk methane mole fraction (x₁) on the saturation pressure: this result allows us to build simplified versions of α–β and fluid models, applicable to the majority of crude oils, and whose formulation depends advantageously on x₁ only.     

Contrasting paleofluid systems in the continental basement: a fluid inclusion and stable isotope study of hydrothermal vein mineralization,Schwarzwald district,Germany

An integrated fluid inclusion and stable isotope study was carried out on hydrothermal veins (Sb‐bearing quartz veins, metal‐bearing fluorite–barite–quartz veins) from the Schwarzwald district, Germany. A total number of 106 Variscan (quartz veins related to Variscan orogenic processes) and post‐Variscan deposits were studied by microthermometry, Raman spectroscopy, and stable isotope analysis. The fluid inclusions in Variscan quartz veins are of the H₂O–NaCl–(KCl) type, have low salinities (0–10 wt.% eqv. NaCl) and high T_h values (150–350°C). Oxygen isotope data for quartz range from +2.8‰ to +12.2‰ and calculated δ¹⁸O_H2O values of the fluid are between ?12.5‰ and +4.4‰. The δD values of water extracted from fluid inclusions vary between ?49‰ and +4‰. The geological framework, fluid inclusion and stable isotope characteristics of the Variscan veins suggest an origin from regional metamorphic devolatilization processes. By contrast, the fluid inclusions in post‐Variscan fluorite, calcite, barite, quartz, and sphalerite belong to the H₂O–NaCl–CaCl₂ type, have high salinities (22–25 wt.% eqv. NaCl) and lower T_h values of 90–200°C. A low‐salinity fluid (0–15 wt.% eqv. NaCl) was observed in late‐stage fluorite, calcite, and quartz, which was trapped at similar temperatures. The δ¹⁸O values of quartz range between +11.1‰ and +20.9‰, which translates into calculated δ¹⁸O_H2O values between ?11.0‰ and +4.4‰. This range is consistent with δ¹⁸O_H2O values of fluid inclusion water extracted from fluorite (?11.6‰ to +1.1‰). The δD values of directly measured fluid inclusion water range between ?29‰ and ?1‰, ?26‰ and ?15‰, and ?63‰ and +9‰ for fluorite, quartz, and calcite, respectively. Calculations using the fluid inclusion and isotope data point to formation of the fluorite–barite–quartz veins under near‐hydrostatic conditions. The δ¹⁸O_H2O and δD data, particularly the observed wide range in δD, indicate that the mineralization formed through large‐scale mixing of a basement‐derived saline NaCl–CaCl₂ brine with meteoric water. Our comprehensive study provides evidence for two fundamentally different fluid systems in the crystalline basement. The Variscan fluid regime is dominated by fluids generated through metamorphic devolatilization and fluid expulsion driven by compressional nappe tectonics. The onset of post‐Variscan extensional tectonics resulted in replacement of the orogenic fluid regime by fluids which have distinct compositional characteristics and are related to a change in the principal fluid sources and the general fluid flow patterns. This younger system shows remarkably persistent geochemical and isotopic features over a prolonged period of more than 100 Ma.     

THE PRIORITY OF LARGE CITIES IN ZIPF RANK-SIZE RULE SYSTEMS

The author seeks to establish possible reasons for differences in the rates of growth of towns within urban systems with rank-size regularities. It is shown that a system follows Zipf s law if the growth of population N _i of the towns of the system follows the regularity M(ΔN _i )/N _i ～ (In N _i - c) where M is the mathematical expectation, ΔN _i is an increment of Ni over a short period of time, ～ stands for “directly proportional,” and c is a constant.     

Simulation of the impact of faults on CO2 injection into sandstone reservoirs

Numerical simulations of multiphase CO₂ behavior within faulted sandstone reservoirs examine the impact of fractures and faults on CO₂ migration in potential subsurface injection systems. In southeastern Utah, some natural CO₂ reservoirs are breached and CO₂‐charged water flows to the surface along permeable damage zones adjacent to faults; in other sites, faulted sandstones form barriers to flow and large CO₂‐filled reservoirs result. These end‐members serve as the guides for our modeling, both at sites where nature offers ‘successful’ storage and at sites where leakage has occurred. We consider two end‐member fault types: low‐permeability faults dominated by deformation‐band networks and high‐permeability faults dominated by fracture networks in damage zones adjacent to clay‐rich gouge. Equivalent permeability (k) values for the fault zones can range from <10^?14 m² for deformation‐band‐dominated faults to >10^?12 m² for fracture‐dominated faults regardless of the permeability of unfaulted sandstone. Water–CO₂ fluid‐flow simulations model the injection of CO₂ into high‐k sandstone (5 × 10^?13 m²) with low‐k (5 × 10^?17 m²) or high‐k (5 × 10^?12 m²) fault zones that correspond to deformation‐band‐ or fracture‐dominated faults, respectively. After 500 days, CO₂ rises to produce an inverted cone of free and dissolved CO₂ that spreads laterally away from the injection well. Free CO₂ fills no more than 41% of the pore space behind the advancing CO₂ front, where dissolved CO₂ is at or near geochemical saturation. The low‐k fault zone exerts the greatest impact on the shape of the advancing CO₂ front and restricts the bulk of the dissolved and free CO₂ to the region upstream of the fault barrier. In the high‐k aquifer, the high‐k fault zone exerts a small influence on the shape of the advancing CO₂ front. We also model stacked reservoir seal pairs, and the fracture‐dominated fault acts as a vertical bypass, allowing upward movement of CO₂ into overlying strata. High‐permeability fault zones are important pathways for CO₂ to bypass unfaulted sandstone, which leads to reduce sequestration efficiency. Aquifer compartmentalization by low‐permeability fault barriers leads to improved storativity because the barriers restrict lateral CO₂ migration and maximize the volume and pressure of CO₂ that might be emplaced in each fault‐bound compartment. As much as a 3.5‐MPa pressure increase may develop in the injected reservoir in this model domain, which under certain conditions may lead to pressures close to the fracture pressure of the top seal.     

Entropy vs. human ontogeny: the Shannon information measure; a reliable general indicator of human health?

ABSTRACT

A measure of health based on exact sciences is not considered by social sciences to evaluate human development. We propose the H measure of information of Shannon ([1948]. “A Mathematical Theory of Communication.” The Bell Systems Technical Journal 27 (3): 379–423, 623–656), renamed as H _cto , as a general indicator of human health which can be subsequently aggregated at any statistical level. Several advantages of H _cto are explained: (i) connections with thermodynamics and information theory; (ii) combination of physical and statistical elements; (iii) measurements of entropy and/or information depending on the reference point, and (iv) a collection of examples based on the scientific literature that supports the application of H _cto . Simplified graphical models of the ontogeny of health condition are also shown. The empirical feasibility of using H _cto is also analysed, by concluding that it could be a tangible reality in the near future.     

CHARACTERIZING THE SEDIMENTARY HISTORY OF CAVE DEPOSITS,USING ARCHAEOMAGNETISM AND ROCK MAGNETISM,ATAPUERCA (NORTHERN SPAIN)

We use a combination of rock magnetism (anisotropy of magnetic susceptibility, AMS) and magnetic polarity to characterize cave deposits and as a proxy for sedimentary fabric. In three localities at the Atapuerca archaeological site (Galeria, Gran Dolina and Sala de los Cíclopes), magnetic foliation (K_max/K_int) is always greater than lineation (K_int/K_min), consistent with a primary, depositional, sedimentary fabric. Our results, although preliminary, reveal a higher degree of anisotropy in autochtonous deposits compared to allochthonous deposits, possibly indicative of a higher hydrodynamic regime in the former. At two localities the magnetic lineation (K_max) defines a cluster, which is thought to be antipodal to the palaeocurrent direction. Hence we are able to retrieve palaeoflow directions in deposits that otherwise lack any other sedimentary structure. We conclude that AMS is a powerful tool for determining the hydrodynamic character of depositional environments in cave sediments at the Atapuerca archaeological site. A better understanding of the depositional environment and how sedimentation occurred allows reconstruction of the karst evolution and ultimately a better definition of human interaction with the environment.     

Fractal analysis of veins in Permian carbonate rocks in the Lingtanchang anticline,western China

Statistical analysis of the thickness distribution of veins in the Lingtanchang structure, southern Sichuan basin, western China, indicates that vein thickness conforms to fractal character and a power‐law distribution, whereas various distributions of veins are indicated by both the spacing distribution and the C_v values. According to geometry and structure, the veins in the Lingtanchang structure can be divided into confined and through‐going veins. The statistical analyses show that confined intralayer veins are consistent with a power‐law distribution in thickness, with D_t values of 1.1–1.7 and a log‐normal distribution in spacing with C_v values of 0.8–0.9. The confined intra‐ to interlayer veins show D_t values of 1.0–1.3 and an exponential distribution in spacing, with C_v values of 0.9–1.0, indicating an unconnected vein network with weak ability for paleofluid flow. However, the through‐going veins show the lowest D_t values of 0.6–0.8 with a power‐law distribution in thickness and power‐law to exponential distribution in spacing with C_v values of 1.5–3.2. Differences in spacing distribution and in the thickness of veins can be explained by different stages of vein growth from confined to through‐going veins. Such processes are dominant with percolating cluster models, which significantly controls spatial distribution of veins and paleofluid flow, and therefore the reservoir conditions in the southern Sichuan basin.