Terra Rossa Research Articles

New evidence for the Palaeolithic in Attica, Greece

Despite Greece’s key geographic position between southeast Europe and southwest Asia, and its potential for documenting hominin dispersals, Lower and Middle Palaeolithic sites are rare. This suggests the need for research to identify deposits that may contain Palaeolithic artefacts. Here we describe 165 quartz and quartzite artefacts with Palaeolithic characteristics (based on technical and morphotypological definitions) from a private collection that was made from erosional lag deposits on the southeastern slopes of Mt. Pendeli and the northern edge of the Spata polje (a large karstic depression filled with terra rossas) in northeast Attica. Artefacts of the same type occur in the region of Ano Souli, another karstic depression. These karstic depressions are of interest because they resemble artefact-bearing deposits found at similar features such as Kokkinopilos in Epirus that have provided datable geologic contexts for Lower and Middle Palaeolithic artefacts. Our study suggests that Attica was frequented by hominins in the Lower and Middle Palaeolithic and that Pleistocene deposits in karstic depressions in Attica may preserve datable contexts for documenting early human activity. The lithic collection described here provides a glimpse of the potential of the region, and we recommend continued archaeological efforts in Attica to investigate the likelihood for buried Palaeolithic sites.

Integrated study of Red Mediterranean soils from Southern Italy

Terra Rossa is a typical Mediterranean soil characterized by an association of the Mediterranean climate, high internal drainage (due to the karstic nature of the underlying hard limestone) and neutral pH conditions. The genesis of this soil is a controversial subject in terms of the origin of the parent material, from the residual underlying (carbonate/dolomite) bedrock and/or from external (aeolian dust) contributions. We apply an integrated approach (chemical, physical, mineralogical and geochemical) to nine soil profiles of terra rossa from Apulia region (southern Italy), in order to investigate the main soil properties relating to soil weathering and pedogenetic processes, as well as to acquire knowledge on soil-bedrock relationships and their origin. Results showed that these terra rossa were generally clayey, had colors (moist) ranging from 2.5YR to 7.5YR Munsell hues and a mineralogical composition of mainly kaolinite, illite/mica and Fe-oxides (hematite and goethite). The pedogenetic indices (Feo/Fed, Fed/Fet) exhibited a generally high degree of crystallinity of iron forms and soil weathering. The correlation between illite/kaolinite ratio and pedogenetic indices, as well as that of kaolinite and hematite with the Feo/Fed ratio indicated that weathering processes in the studied environments promoted the formation of both kaolinite and hematite from illite/mica minerals. Since the hematite/goethite ratio was generally higher than 1, rubification processes also occurred in these soils. The comparison of the geochemical composition of terra rossa with that of insoluble residues (obtained from the underlying limestone and dolomite rocks) indicated that a group of elements (such as Ti, Mn, Th) was more concentrated in terra rossa than in the insoluble residues, whereas another group (made up of Fe, K, Ca, Cr, Cu, Zr, Zn, Rb, Ni, As, Sr and Pb) was more concentrated in the insoluble residues than in terra rossa. The two groups of elements were considered to be different as a result of their having different sources, the first being allochtonous and the second mainly authoctonous. The additional correlation of Ti, Mn and Th with terra rossa clay content seemed to support the hypothesis of wind-blown long distance transport for these elements.

A Phytosociological of Plant Communities and Biodiversity in the East-South of Idna Village-Hebron of Palestine

This paper presents a floristic and vegetation study of the territories of the Idna-Hebron of Palestine, corresponding to one area with three different names as Abu Salman Forest Reserve, Khallet Osman mountains, and Hamra Aslimi. These sites are very important at a local level of the flora with a high endemic rate. The floristic analysis revealed the existence of 48 species, of which 10 (20.83%) are endemic endemic. Seventeen plots of vegetation distributed in one area dominated and have been analyzed in this study. Methodology, the phytosociological approach is based on the Braun-Blanquet method. The results revealed three different kinds of forests, one dominated by the endemic Pino halepensis-Quercetum lookii, which is peculiar to the inframediterranean dry-thermomediterranean environments, with the terra rossa and brown rendzinas territory. The second type of forest is dominated by the Pistacio palaestinae-Ceratonietum silique, which is growing in the dry-subhumid ombrotype and the terra rossa and brown rendzinas territory. The third group of the forest of Khallet Osman and Hamra Aslimi dominated by Quercus lookii-Tamaricetum palestineae. Finally, in this study there are three associations and tow alliances are proposed as new Syntaxa based on statistical and phytosociological analyses in the study area.

Provenance and formation of the red palaeosol and lithified terra rossa-like infillings on the Island of Susak: A high-resolution and chronological approach

Red palaeosol (RP) covering the carbonate basement exposed at the bottom of the loess section and lithified terra rossa-like materials situated in cavities (LTR1) and karstified fissures (LTR2) in Cretaceous limestones were investigated by means of high-resolution approach, to give a systematic and deeper palaeopedological insight into reddish materials and the exposed red palaeosols on the island of Susak. Both, selected geochemical indicators of weathering (Al/Si, (Na + K)/Al and Fed/Fet) and provenance (La/Ce), as well as detailed mineralogical analysis clearly showed differences among LTR1, LTR2 and RP, respectively. LTR1 and LTR2 represent erosional remains of different soils that existed on the surface of the limestone bedrock prior to the formation of the RP. LTR2 has the highest ZTR (zircon-tourmaline-rutile index) index and contains bauxite minerals (gibbsite and boehmite), clays (kaolinite and mixed-layer clay minerals), and haematite. LTR2 bears characteristics of reworked bauxitic materials mixed with other soils that existed on the surface of the carbonate basement. Those materials might have been mixed and transported until they were captured in the karstified fissure, and, subsequently interlocked with calcite veins and lithified. This might have happened from the Eocene age on. Our attempt to resolve the age of LTR2 formation more precisely, using palaeomagnetic investigations, did not give unambiguous results because the extremely viscous behaviour of the LTR2 samples hinders the acquisition of a stable remanent magnetisation. If we exclude the secondary calcite, LTR1 bears typical mineralogical and geochemical characteristics (e.g. Fed/Fet ratio) similar to those of Istrian terra rossa. Insoluble residues of Cretaceous limestone might have been the main parent materials for the LTR1 formation while the most likely additional fluxes influencing terra rossa formation on the island of Susak were aeolian dust and flysch. The erosion remains ended in limestone cavities and were mixed with cm to dm sized angular and subangular limestone clasts and, subsequently, interlocked with calcite veins and lithified. The investigated RP profile comprised the following mineral horizons: Bwb1-Bwb2-Bwb3-R. The RP formed in a lithologically uniform material that dominantly presents a mixture of loess and, partly, remains of older soils (e.g. rounded clay coatings not related to macrovoids) that existed on the surface of the Cretaceous limestone. Fed/Fet ratio in RP reflects a low degree of weathering of Fe-containing primary silicates. Therefore, we can conclude that the RP does not fit a rather limited variation of selected Fe-oxide characteristics typical for terra rossa. The investigated RP was classified independently of the overlying material. The full name of the palaeosol that we classified is as follows: Hypereutric Chromic Cambisol (Episiltic, Endoloamic). Since no reversal of the EMF was recorded in the RP, we concluded that the RP formed during the Brunhes epoch. Luminescence dating was applied to establish the age of the RP. Based on the acquired data, we assume that the RP very likely formed during the Penultimate Interglacial (OIS7).

Strong release of viruses in fracture flow in response to a perturbation in ionic strength: Filtration/retention tests and modeling

Effluents derived from a municipal wastewater treatment plant were used for virus filtration/retention experiments by using a horizontal laboratory filter. Filtration tests were performed to examine how soil geochemical heterogeneity and fracture patterns affected the transport of viruses in groundwater in order to model the influence of reductive perturbations in ionic strength (IS) during wastewater filtration. Although perturbations of IS and velocity are known to result in resuspension of colloids, we found that the effect of soil geochemical heterogeneity can produce strong and instantaneous virus releases in fractured aquifers, likely an internal additional source of viruses. Sixteen limestone slabs were packed in a PVC box filter at the Bari Laboratory (South Italy) to replicate wastewater filtration throughout a fractured medium similar to the Bari carbonate aquifer. Terra rossa, which is an aggregate of sand, silt and clay, was unevenly spread on the surface of each limestone slab within the filter. Since the mineralogical composition of terra rossa includes iron (hematite, magnetite, and goethite) oxides, the soil exhibited localized unfavorable colloid/collector interactions for attachment. In contrast, soil-free parts of the fracture surfaces maintained favorable colloid/collector interactions. We found in our experiments that the lowering of IS due to the reduction of water salt content, which could occur during runoff injections after rainfall, might be sufficient to cause strong detachment of viruses from fracture surfaces, allowing further migration into the groundwater. The model in this work can predict the count and pathways of released viruses in groundwater fractures under soil geochemical heterogeneity and originated by reductions of IS, by using analytical solutions.

Influence of the geological setting on the REE geochemistry of estuarine sediments: A case study of the Zrmanja River estuary (eastern Adriatic coast)

Increasing use of rare earth elements (REE) in many new technologies results in their increasing presence in the environment and consequently in natural water systems. The Zrmanja River estuary represents a small, semi-closed system located in a karstic landscape of the eastern Adriatic coast characterised by the prevailing red soil (terra rossa) cover, numerous bauxite pits and the proximity of a decommissioned alumina plant, i.e. sources of geomaterials enriched in rare earth elements. To study the influence of such a substrate on estuarine sediment geochemistry, distribution of REEs in the surface sediments of the Zrmanja River estuary and surrounding soils were investigated. Both sediment and soil samples displayed significant variation in terms of REE concentrations as well as their normalised patterns, with overall highest REE levels measured in bauxitic soils (ΣREE 333–596mgkg−1); up to an order of magnitude higher than in other samples. In estuarine sediments, ΣREE ranged from 29.7mgkg−1 to 180mgkg−1, and displayed an increase along the estuary transect. Highest levels of rare earths in sediments of the Zrmanja River were observed in locations closest to the former alumina plant, indicating a transfer of particles rich in REE from the anthropogenically degraded environment in the vicinity of the factory and its influence on the geochemistry of the estuarine sediments. Sediment REE normalised patterns and associated fractionation parameters (ΣLREE/ΣHREE, (La/Nd)NASC, (La/Yb)NASC) showed similarity to those observed for soil samples, confirming a significant influence of local lithological and pedological setting on the sediment REE composition. Moreover, spatial changes in these parameters in sediments clearly followed the changes in nearby soils and can be differentiated on a relatively small scale.

MECHANICAL COMPOSITION OF THE SOILS FORMED ON LIMESTONES AND DOLOMITES IN THE REPUBLIC OF MACEDONIA

The paper presents results from the research of the influence of the parent material on the mechanical compo-sition of calcomelanosols, calcocambisols and terra rossa. The contents of the fine soil separates in the calcomelano-sols vary depending on the subtype. The physical sand fraction (coarse sand + fine sand) in the Amo horizon amounts 44.81% in the organomineral calcomelanosols, 40.13% in the organogenic and brownised calcomelanosols 36.52%. In the (B)rz horizon in the brownised calcomelanosols it amounts 32.64%. The content of clay + silt or physical clay in the Amo horizon amounts 55.19% in the organomineral calcomelanosols, 59.87% in the organogenic and the high-est content is in the brownised calcomelanosols 63.48%. The average value of this fraction in the horizon (B)rz in the brownised calcomelanosols amounts 67.36%. In the calcocambisols the average content of the fraction physical sand in the Amo horizon amounts 33.43%, and in the cambic horizon (B)rz 22.50%. In the terra rossa the fraction physical clay is represented with a greater percentage related to the physical sand fraction. In the Amo horizon, in the physical clay fraction, the clay fraction is predominant, average 43.08%, and 52.13% in the cambic horizon, and 24.90% in the Amo horizon and 19.37% in the (B)rz horizon for the silt fraction. From a research soils 36% of the soils are formed on massive limestone, 13% are formed on dolomitic limestone and bituminous marbles, 16% on plate (flat) limestone, 10% on dolomitic marbles and 12% on laminated (plate) dolomite and calcite.

Tree-induced changes in a terra rossa soil under olive.Observations from an integrated field study

A range of indicators including chemical, physical, morphological, and clay mineral properties were investigated to support an integrated evaluation of the changes induced by a long established olive grove on a red Mediterranean soil. The study area was located in Sardinia (Italy). Two soil profiles were studied in a site where land use had remained unchanged for the previous 150 years: one under the canopy and around the trunk of an olive tree and one between the trees. Chemical analyses including organic matter fractions were performed by horizon. Undisturbed soil samples were collected from aggregates for thin section and scanning electron microscopy (SEM) analyses, complemented by clay mineralogy. Relative compaction was observed in tree topsoil due to the pressure of the anchoring roots. Lower compaction, higher porosity, and less developed micro-aggregates were observed in deeper horizons in relation with the loosening action induced by roots. Sharper vertical chemical gradients were determined under the tree. Stress features were observed in thin sections from all the horizons. Traces of smectite were determined as indicator of past shrink-swell processes suggesting that the present-day dominance of illite-like minerals might be explained by transformation of smectite induced by pedogenesis and by the long-lasting K-enriching action of the plants. Our findings indicate the need to undertake more systematic, integrated, and comparative future research on this subject.

Assessing automated image analysis of sand grain shape to identify sedimentary facies, Gran Dolina archaeological site (Burgos, Spain)

Gran Dolina is a cave (Sierra de Atapuerca, Spain) infilled by a 25m thick sedimentary record, divided into 12 lithostratigraphic units that have been separated into 19 sedimentary facies containing Early and Middle Pleistocene hominin remains. In this paper, an automated image analysis method has been used to study the shape of the sedimentary particles. Since particle shape is interpreted as the result of sedimentary transport and sediment source, this study can provide valuable data about the sedimentological mechanism of sequence formation. The shape of the sand fraction in 73 samples from Gran Dolina site and Sierra de Atapuerca was analyzed using the Malvern Morphologi G3, an advanced particle characterization tool. In this first complete test, we used this method to the published sequence of Gran Dolina, defined previously through field work observations and geochemical and textural analysis. The results indicate that this image analysis method allows differentiation of the sedimentary facies, providing objective tools to identify weathered layers and measure the textural maturity of the sediments. Channel facies have the highest values of circularity and convexity, showing the highest textural maturity of particles. On the other hand, terra rossa and debris flow samples show similar values, with the lowest particle maturity.

THE STATE OF SOIL ORGANIC MATTER IN DIFFERENT PHYSICAL FRACTIONS DEPEND ON LAND USE TYPE

UDK 631.417(497.6)
 Known fact is that arable soils compared with correspondent native soils differ in the state of soil organic matter (SOM) and that agricultural practices halved content of soil organic carbon in last decades. Further, soil structure or aggregation mediates many biological and chemical processes in soil and influence on protecting of SOM. The objectives of this paper is to analyze how the different land use (forest, grassland and arable soil) effects on quality and quantity of SOM in different physical fraction. In particular, it is important to determine what pool (physically separated fraction) of SOM is most sensitive on cultivation and what pool is more resistant to mineralization.
 The research is carried out on two soil type with different texture, Pseudogley and Terra rossa, in condition of different climate and soil management. Two groups of SOM analysis are singled out: 1) quantify SOC and N storage, and δ13C by horizons; and 2) quantify the SOC and N in the following physically separated fractions of SOM: a) coarse and fine particulated organic matter (POM) density <1.8 gcm-3; b) occluded POM in stable microaggregates 53-250 µm; and c) SOM in small microaggregates <53 µm.

Mineral composition of kale genotypes grown in three soils

The leafy kale (Brassica oleracea var. acephala) is known as valuable source of different minerals. The objective of this study was to determine the effect of two kale genotypes cultivation in three phosphorus deficient soils common for coastal Croatia, on mineral composition of shoots and roots. The study was conducted in a greenhouse located in Split, Croatia during winter 2012. Plants of kale genotypes, cultivar 'Red Russian' and Croatian accession Pula were planted in (3 L) pots filled with three soils: Rhodic cambisol NDASH terra rossa, Rendzic leptosol, and Fluvisol Eutric Calcaric. The design was a randomized complete block with four replications. Shoot and root samples were analyzed using inductively coupled plasma NDASH optical emission spectrometry for Ca, Mg, Mn, Zn, Fe, Cu, and Mo concentrations. In the shoots, concentrations of all minerals were significantly affected by cultivation in different soil. Also, genotypes differed in Ca, Mg, Mn and Zn concentrations, while interactive effect of soil type and genotype were noted for Mn, Zn, and Cu. In the roots, all minerals significantly varied depending on soil type, while genotypes differed in Ca, Mg, Zn, and Mo. The interaction of genotype and soil type was significant for Ca, Mg, and Mo concentrations in roots. Mineral composition of kale tissues can be result of different chemo-physical soil characteristics, and also genetic variability in nutrient uptake and translocation.

Petrography, micromorphology and genesis of Holocene pedogenic calcrete in Al-Jabal Al-Akhdar, Sultanate of Oman

Holocene pedogenic calcrete nodules occur within Quaternary terra rossa soil that fills shallow phytokarst cavities in the Permian-Triassic carbonate sequence of Al-Jabal Al-Akhdar in the Sultanate of Oman. They are preferentially clustered around plant roots and are almost wholly formed of calcite. Holocene pedogenic calcrete nodules developed within a Mediterranean-like climate that is characterized by intermittent wet and dry seasons. Petrographic examination revealed that the host terra rossa soil is partially calcitized and that the calcrete nodules consist of smaller coalesced diffused and/or discrete granular nodules. The latter consist of several types of rhizoliths floating in a groundmass formed of micrite and microspar, as well as spar to a lesser extent. Several textures of calcrete groundmass are recognized; the most common is partially neomorphosed micrite. Three types of rhizoliths are recognized, root moulds, root casts and petrified (calcified) root tissues. The latter were developed by mimic replacement of the tissue cells by cytomorphic calcite. SEM investigation of the calcite forming the calcrete nodules revealed that it consists of closely stacked sheets formed of calcareous nanoglobules agglutinated by EPS and entombed calcareous microbial fossils, which indicate a biogenic origin.The calcareous nature of the bedrock, climatic conditions and prevalence of biological activities of microorganisms associated with the plant root system in the host soil have significantly controlled the development and texture of these nodules. The relative abundance of scalenohedral calcite within the calcrete groundmass is attributed to the impact of Mg ions and organic compounds. It has been concluded that the studied pedogenic calcrete is a type of freshwater terrestrial thrombolitic microbialite. This study may help improve the understanding of the palaeoenvironmental conditions of analogue fossil calcretes.

Element geochemical characteristics of a soil profile developed on dolostone in central Guizhou, southern China: implications for parent materials

This study presents bulk chemical compositions of the Tongmuling soil profile, which developed on dolostone, and the overlying strata covering the bedrock in the central Guizhou province (southern China). The chemical weathering characteristics of the studied profile were investigated and the inheritance relationships between the terra rossa and overlying strata were discussed. The results show that there is no remarkable variation in the major elements and weathering indices from the rock–soil interface to the topsoil, indicating that the studied profile was not typical for in situ crustal chemical weathering. The terra rossa were mainly composed of SiO2, Al2O3 and Fe2O3. Compared with the insoluble residues and overlying strata, the terra rossa are characterized by an enrichment of Y and Cs and depletion of Ba and Sr. The subsoil shows a notable Ce negative anomaly, characterized by heavy rare earth element enrichment (L/H = 1.55–3.74), whereas the topsoil shows a positive Ce anomaly with light rare earth element enrichment (L/H = 5.93–9.14). According to Laterite-forming capacity estimates, the terra rossa could not have only been formed from acid-insoluble residues from the bedrock; Al2O3 versus Fe2O3 and Nb plotted against Ta show significant positive correlations between the terra rossa and overlying strata. The Eu/Eu* versus GdN/YbN and ternary diagrams for Sc, Th, Zr, and Ta suggest that the overlying strata could also provide parent materials for the genesis of terra rossa.

Stable carbon and oxygen isotopes of terra rossa in Guizhou Province of China and their relationship to climate and ecology

This paper analyzed stable carbon and oxygen isotopic changes in organic matter (δ 13CSOM) and disseminated carbonate (δ 13CSC and δ 18OSC) in four terra rossa profiles in Gouzhou, southwestern China. The objectives were to understand more information about climate change in this area and to determine whether the isotope values of disseminated carbonate in terra rossa preserved a record of environmental change and to distinguish environmental sources that may have influenced the isotopic chemistry. Results suggested that carbonate in terra rossa is mainly pedogenic carbonate, and its formation is closely associated with root activities. The δ 13CSOM variations indicate a climate change into warmer and drier conditions at about 6000–8000 a BP, 12000–14000 a BP and 28000 a BP. Plants were more depleted in δ 13C when carbonate precipitated. Compared with the δ 13CSOM, the δ 13CSC tends to reflect more average climate change information. Most large variations of the δ 13CSC and δ 13CSOM between adjacent sampling layers are accompanied with the change in soil color and texture, suggesting a certain connection between the δ 13C and the soil properties. This study found a positive linearity between δ 13CSC and δ 18OSC; a striking different value and correlation coefficient in different sites may provide a meaningful signal of regional climate change.

Cave-fills in Miocene–Pliocene strata on Cayman Brac, British West Indies: Implications for the geological evolution of an isolated oceanic island

An 8-m-high wall in a quarry on the west end of Cayman Brac exposes the upper part of the Cayman Formation (Miocene), the lower part of the overlying Pedro Castle Formation (Pliocene), and the Cayman Unconformity, which is a karstic unconformity that separates these formations. The modern-day karst surface caps the Pedro Castle Formation. This exposure also includes cross-sections through two filled caves—the “Lower Cave” (>8m long, up to 2.5m high) and “Upper Cave” (>23m long, up to 2 m high)—that are housed in the Cayman Formation and Pedro Castle Formation, respectively.The Lower Cave is filled with caymanite, which is formed of laminated, varicolored dolomitized mudstones, and grainstones that contain scattered marine fossils (e.g., foraminifera, red algae). This cave, connected to the Cayman Unconformity by a small-diameter tunnel, evolved as part of the karst system that developed during the Messinian lowstand (7.3–5.3Ma). The cave was filled and dolomitized prior to deposition of the Pedro Castle Formation. The Upper Cave is filled with a wide spectrum of lithotypes, including dolostones, calcareous mudstones, terra rossa, gastropod coquina, coated grains, and speleothems. U/Th dating indicates that some of the flowstones are >500,000 years old whereas others are only ~ 21,000 years old. Dolostones and mudstones in the basal part of the Upper Cave contain marine fossils (foraminifera, red algae) whereas the younger deposits are devoid of such fossils.The Upper Cave and its deposits developed after the sediments of the Pedro Castle Formation had been deposited and lithified. Development of the cave filling deposits, which includes a clear transition from marine to non-marine influences, was controlled by eustatic sea-level changes and/or westward tectonic tilting of Cayman Brac that occurred after the Pedro Castle Formation became exposed, probably during the Late Pliocene.

Contrasting environmental memories in relict soils on different parent rocks in the south-western Italian Alps

Soils on the Alps are usually weakly developed, both because of the extensive Pleistocene glaciations, and because of slope steepness and climate enhancing erosion. However, on some stable, relict surfaces, particularly in the outermost sections of the Alpine range, some highly developed soils are apparently in contrast with Holocene soil forming conditions. In this work we assess the extent of pedogenesis in some of these soils, located under montane-level vegetation in the Ligurian Alps (SW Piemonte, Italy), and relate it to the effects of climate and parent material.The considered well developed profiles showed signs of extremely different pedogenetic processes on the different lithotypes. In particular, Podzols with extremely thick E horizons (up to more than 2 m thick) and very hard, thick ortstein or placic horizons were formed on quartzite. Reddish “terra rossa” Luvisols were formed on limestone. Red, extremely acidic Alisols were formed on shales. The chemical properties, the micromorphology and the clay mineralogy demonstrated high intensity pedogenic trends, and were characteristic of processes usually occurring under different climates.They may therefore represent excellent pedo-signatures of different specific past climatic/environmental conditions, as a response of different lithologies to specific soil-forming environments, which range from warm and humid climates typical of red Alisols and Luvisols, to cool and humid/wet climates leading to the formation of Podzols with ortstein/placic horizons.

Effect of Organic Carbon Fraction on Long-term Atrazine Elution Tailing for Two Heterogeneous Porous Media: Experimental and Modeling Approach

A series of column experiments was conducted to evaluate the effect of organic carbon fraction on long-term atrazine elution tailing for calcareous soil (foc = 0.97 %) and calcareous soil with 10 % by weight terra rossa amendment (foc = 1.20 %). Effluent atrazine concentrations were monitored for approximately 400 pore volume to understand the influence of controlling sorption–desorption kinetics on long-term tailing behavior. Laboratory studies showed that the sorption of atrazine was described by rate-limited, nonlinear reversible processes for both soils. Atrazine transport exhibited extensive elution tailing for all experiments due to the presence of hard carbon components such as black carbon and kerogen in both soils. This nonlinear sorption and extensive atrazine tailing behavior were more pronounced and extensive for soil with terra rossa amendment due to the addition of approximately 20 % organic carbon including 10 % hard carbon components from terra rossa soil. A mathematical model incorporating nonlinear, rate-limited sorption/desorption described by a continuous distribution function was used to successfully simulate atrazine transport early-time breakthrough and long-term concentration tailing for both porous media.

Chemostratigraphy of an Ordovician–Silurian carbonate platform: δ13C records below glacioeustatic exposure surfaces

Research Article| January 01, 2015 Chemostratigraphy of an Ordovician–Silurian carbonate platform: δ13C records below glacioeustatic exposure surfaces David S. Jones; David S. Jones Geology Department, Amherst College, 11 Barrett Hill Road, Amherst, Massachusetts 01002, USA Search for other works by this author on: GSW Google Scholar Roger C. Creel; Roger C. Creel Geology Department, Amherst College, 11 Barrett Hill Road, Amherst, Massachusetts 01002, USA Search for other works by this author on: GSW Google Scholar Bernardo Rios; Bernardo Rios Geology Department, Amherst College, 11 Barrett Hill Road, Amherst, Massachusetts 01002, USA Search for other works by this author on: GSW Google Scholar Danielle P. Santiago Ramos Danielle P. Santiago Ramos Geology Department, Amherst College, 11 Barrett Hill Road, Amherst, Massachusetts 01002, USA *Current address: Department of Geosciences, Princeton University, Guyot Hall, Princeton, New Jersey 08544, USA. Search for other works by this author on: GSW Google Scholar Geology (2015) 43 (1): 59–62. https://doi.org/10.1130/G36236.1 Article history received: 02 Sep 2014 rev-recd: 30 Oct 2014 accepted: 05 Nov 2014 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation David S. Jones, Roger C. Creel, Bernardo Rios, Danielle P. Santiago Ramos; Chemostratigraphy of an Ordovician–Silurian carbonate platform: δ13C records below glacioeustatic exposure surfaces. Geology 2015;; 43 (1): 59–62. doi: https://doi.org/10.1130/G36236.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The use of carbon isotope stratigraphy to construct time lines for stratigraphic correlation requires synchronous changes in carbon isotope ratios (δ13C) to be preserved in carbonate-dominated strata. Such changes are commonly interpreted to reflect primary secular variation in ocean chemistry. However, negative δ13C anomalies developed in Pliocene–Pleistocene carbonate platforms following glacioeustatic sea-level fall due to remineralization of terrestrial biomass during meteoric diagenesis. These anomalies are similar in structure and magnitude to some Neoproterozoic δ13C records, opening the possibility that the Neoproterozoic δ13C anomalies have a meteoric origin derived from a large terrestrial biosphere. Here we test the hypothesis that a large terrestrial biosphere existed prior to the Silurian–Devonian land-plant radiation by examining δ13C records of subaerial exposure surfaces formed in a shallow-water carbonate platform during the Ordovician–Silurian icehouse. The exposure surfaces include an unconformity at the Ordovician-Silurian boundary with terra rossa and dissolution-collapse breccia, and a lower Silurian quartz sand layer feeding a 50-m-deep system of karst pipes. There is no evidence for δ13C depletion beneath either exposure surface. Strontium concentrations in the rocks are low (10–120 ppm) and covary with δ18O; oxygen isotope ratios, however, do not positively correlate with δ13C. Our results suggest that there was no significant terrestrial biosphere during Ordovician–Silurian time, and by extension, that Neoproterozoic negative carbon isotope anomalies cannot be explained by meteoric diagenesis. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Bulk and clay mineral composition indicate origin of terra rossa soils in Western Herzegovina

The B horizons of terra rossa soils developed on three different carbonate lithologies having variable insoluble residue contents were studied in Western Herzegovina. Comparison of their composition and properties illustrates to what extent mineral (especially clay mineral assemblage) and particle size composition of those horizons and the insoluble residue of the underlying carbonate rocks can be used as indicators of the polygenetic nature of terra rossa in this region. Terra rossa B horizons have characteristic red colours, neutral to slightly acid pH, high base saturation with calcium as the predominant cation and high CIA (Chemical Index of Alteration). The CIA values obtained are generally in accordance with mineral composition and particle size distribution of the analysed B horizons. The predominant clay mineral phases in B horizons and related insoluble residues match. Kaolinite is the predominant clay mineral phase in the B horizons overlying carbonate rocks containing low amounts of insoluble residue, while smectite predominates in calcarenites areas with a high insoluble residue content. However, the presence of plagioclase, gibbsite, chlorite-vermiculite mixed layer mineral and vermiculite in B horizons overlying carbonate rocks containing low amounts of insoluble residue support a polygenetic origin for the terra rossa. In contrast, terra rossa formed on calcarenites containing high amounts of insoluble residue might have formed almost exclusively from the parent carbonate rock although some influence of external materials (e.g. gibbsite) cannot be excluded. This investigation shows that in Western Herzegovina, an area with no important aeolian input, the content and mineral composition of carbonate rock insoluble residue plays a major role in terra rossa composition. We can tentatively conclude that the lower the insoluble residue content of the parent materials, the greater is the expectation of a more polygenetic origin for the terra rossa.

Petrographic and geochemical features of sinkhole-filling deposits associated with an erosional unconformity on Grand Cayman

On Grand Cayman, exposures of dolostones belonging to the Cayman Formation (Miocene) represent an erosional unconformity that has been developing since the late Pliocene (~3.6Ma). Sinkholes that developed during this time have remained open or become partly to fully filled with various combinations of rootcrete, breccias, loose limestone and dolostone lithoclasts, and white, red and orange limestones. These sinkhole-filling deposits have different geochemical attributes to the Neogene and Pleistocene marine carbonates that form the bedrock of the island. The deposits in the sinkholes formed in response to the variations of sea level, climate, exposure, and vegetation that developed during the period when the erosional unconformity was developing.The rootcrete, oncoids, red and orange limestones are terrestrial in origin, whereas the limestone and dolostone lithoclasts and white limestones are derived from marine deposits. On the erosional unconformity, intense root activity led to the formation of rootcrete and terrestrial oncoids but also selectively blackening reworked marine carbonates. The red and orange limestone matrices, which formed under more arid conditions, contrast with the other sinkhole-filling deposits that formed during periods when the climate was semi-arid to humid. The distinctive REE signatures of the sinkhole-filling deposits, which are different from those of the bedrock limestones and dolostones, can probably be attributed to trace amount of terra rossa and/or airborne Saharan-derived dust that are present in those deposits.