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Volcanoes produce probably the most spectacular geological phenomena on Earth. Any of their eruptions can have a strong consequence on the surrounding environment, often captured in great detail in the sedimentary records of volcanically active regions. In addition, flank landslides and background erosive processes affecting volcanic sequences release volcanic particles that circulate within sedimentary environments up to billions of years after their generation. Therefore, exploring volcanically influenced sedimentary environments is an exciting and challenging scientific exercise requiring insights across multiple geological disciplines, drawing upon an increasing varied range of expertise and analytical approaches from across the geoscientific community. This book aims to provide an updated collection of works that illustrate the state-of-the-art in this topic, and to define the future directions of the geological sciences in utilizing and interpreting sedimentary records of volcanism.

The genesis of particles and their transport mechanisms are the two fundamental factors driving the accumulation of sediments associated with volcanism or derived from volcanic sources. These factors are therefore the most important criteria on which to base a useful classification of sediments in such environments. However, the relative significance of the nature of particles v. the transporting mechanism forming a deposit varies in existing terminological schemes: those schemes applied where volcanological contextual information is available tend to give precedence to the transportation process; whereas sedimentological schemes examining ancient deposits tend to focus principally on the nature of particles. Here, we provide an outline of the challenges in classifying volcanically derived sediments and put forward a scheme that aims to bridge current terminological differences and accommodate variable levels of uncertainty. This work defines three endmembers ( primary volcaniclastic , secondary volcaniclastic , volcanic epiclastic ) that correspond to (a) deposits whose particles are produced, transported and emplaced directly by volcanic mechanisms; (b) deposits whose particles are produced directly by volcanic events but transported and accumulated by non-volcanic mechanisms, either in continuum with the events or after interim storage; (c) deposits whose particles are produced by weathering/erosion of volcanic terrains and transportation of derived material by non-volcanic mechanisms. When the complex combination of genetic and transportation processes accumulating volcaniclastic sequences is not clear, but a strong relationship between an eruptive event and the studied volcaniclastic deposit can still be demonstrated, a further category ( volcanogenic ) has been introduced.

Volcaniclastic deposits have been extensively analyzed in several settings in the Pacific and circum-Pacific area. Recent volcaniclastic products from Atlantic oceanic islands offer another opportunity to add new data and be an important key to a better understanding of volcanic imprints on the sedimentary record. The Cabo Verde archipelago is an Atlantic Oceanic plateau with late Oligocene to Holocene volcanism. Outcrops consist mainly of mafic and strongly alkaline and ultra-alkaline volcanic (pyroclastic and lava flows) and less abundant intrusive rocks with minor carbonatites and carbonate sedimentary rocks, constituting a multiple-provenance assemblage for the sandy beaches surrounding the islands. Currently, climate is semiarid to hyperarid with ephemeral and intermittent streams. Thirty-six samples of beach sand from six principal Cabo Verde Islands were selected for petrographic inspection. On average, beach sands constitute a volcanolithic petrofacies. A relative increase in carbonate limeclasts and bioclasts dilutes the pure volcaniclastic contribution mainly on the older island beaches (Sao Vicente, Sal, and Boa Vista). The major components of Cabo Verde beach sands are highly variable; in general, composition is a function of island morphological evolution and age. Thus, beaches of the younger islands (Sao Nicolau, Santiago, and Fogo) consist mainly of volcanic lithic fragments, and monomineralic grains of dense minerals such as olivine, pyroxene, and amphibole, and single grains of plagioclase and anorthoclase. By contrast, beaches of older eastern islands (Sal, Boa Vista, and Sao Vicente) contain more calcareous bioclasts, micritic and/or sparitic sedimentary lithic grains. The presence of carbonate grains suggests provenance from shallow carbonate platforms developed during periods of volcanic quiescence. Cabo Verde volcanic sandy fractions are composed mostly of black, brown, and orange glassy volcanic particles exhibiting microlitic, lathwork, and vitric textures. Volcanic particles with lathwork textures are linked to mafic provenance assemblages (nephelinites, basanites, and tephrites). The content of glassy particles is nearly constant in all beaches, and both hydroclastic and epiclastic processes are reflected in these populations of glassy grains. Boa Vista, Sao Vicente, and Santiago beaches contain higher proportions of sideromelane, linked to recent coastal volcanism, and lower proportions of orange and black glassy particles. The concentration of orange glass particles in the beaches of Santiago Island is higher than in the other island beaches. These orange glassy textures have been preserved even if they were sourced from the intensely altered Ancient Eruptive Complex, representing the pre-Miocene seamount stage of Santiago Island. A very small percentage of altered labile monocrystalline grains such as olivine and the paucity of altered volcanic components reflect the weathering-limited erosion regime of the islands. The exposed phonolitic lava flows that occupy only a minor surface part of the inland source produce particles with microlitic texture in sand beaches. Thus, this texture is not exclusive to andesitic, basaltic, and basaltic andesites sources, suggesting the need for a review of these particles as source-sensitive provenance signals.

The use of mineral interfaces, in sand-sized rock fragments, to infer the influence exerted by mechanical durability on the generation of siliciclastic sediments, has been determined for plutoniclastic sand. Conversely, for volcaniclastic sand, it has received much less attention, and, to our knowledge, this is the first attempt to make use of the volcaniclastic interfacial modal mineralogy of epiclastic sandy fragments, to infer mechanical durability control at a modern beach environment. Volcaniclastic sand was collected along five beaches developed on five islands, of the southern Tyrrhenian Sea (Alicudi, Filicudi, Salina, Panarea and Stromboli) from the Aeolian Archipelago, and one sample was collected near the Stromboli Island volcanic crater. Each sample was sieved and thin sectioned for petrographic analysis. The modal mineralogy of the very coarse, coarse and medium sand fractions was determined by point-counting of the interfacial boundaries discriminating 36 types of interfaces categories, both no-isomineralic and/or no iso-structural (e.g., phenocrystal/glassy groundmass or phenocrystal/microlitic groundmass boundaries) and iso-mineralic interfaces, inside volcanic lithic grains with lathwork and porphyric textures. A total of 47,386 interfacial boundaries have been counted and, the most representative series of interfaces, from the highest to the lowest preservation, can be grouped as: a) ultrastable interfaces, categorized asPl (Plagioclase)/Glgr (Glassy groundmass) > > Px (Pyroxene)/Glgr > > Ol (Olivine)/Glgr > > Op (Opaque)/Glgr > > Hbl (Hornblende)/Glgr> > Bt (Biotite)/Glgr > > Idd (Iddingsite)/Glgr > > Rt (Rutile) / Glgr; b) stable interfaces, categorized asPl/Migr (Microlitic groundmass) > > Op/Migr > > Px/Migr > > Ol/Migr; c) moderately stable interfaces, categorized asOp/Px > > Op/Hbl > > Px/P > > Ol/Pl> > Bt/Op; and d) unstable interfaces, categorized asPl/Pl > > Px/Px > > Ol/Ol > > Op/Op > > Hbl/Hbl > > Bt/Bt.Grains, eroded from the volcanic bedrock, if affected solely by abrasion, developed a rounded and smoothed form, with prevailing no-isostructural interfaces such as Plagioclase/Glassy groundmass, Pyroxene/Glassy groundmass and Olivine/Glassy groundmass interfaces. Grains that during transport suffered fracturing and percussion have a sharp and angular form: these combined transport mechanisms produce mainly volcanic sandy grains with iso-structural interfaces, such as Pl/Pl, Px/Px, Hbl/Hbl, and, to a lesser extent, Bt/Op and Bt/Glgr interfaces.

Saprolite is the weathered rock below the soil and constitutes the least researched region of the regolith. The association between saprolithology and pedology can contribute to a better understanding of the whole regolith. The Triunfo massif in the state of Pernambuco (NE Brazil) is a natural laboratory suitable for the study of regoliths derived from crystalline rocks under a climate gradient, from the semiarid climate at the base to a humid climate at the top, due to an orographic effect of climate. In this work, we integrated pedology with saprolithology for a taxonomic description of three regolith profiles along the climate gradient in Triunfo massif to better understand the regolith properties. We evaluated the climate effect on the physical, chemical, and morphological properties in horizons and layers of regolith profiles (depth: 2.0 m). The results indicated that a) the integration of taxonomic systems and morphological description protocols of the soil and saprolites in field studies is possible and can contribute to studies on the properties of the whole regoliths, b) the most developed soils were described under wetter climates. However, the climatic gradient did not significantly influence the weathering degree of the saprolite layers below these soils, c) the greater depth and the Bt horizon in the soil under humid climate attenuated the weathering intensity in the underlying saprolite, resulting in saprolite layers with weathering degrees similar to those described in the regolith profile under the semi-arid climate, d) the weathering degree did not advance only from top to bottom, it also moved to zones of greater biological activity, resulting in preferential weathering of the saprolite structure in pedoplasmation zones, e) there is a need to correct the values of physical and chemical properties of the saprolite layers determined in fractions

Porous and permeable crystalline rocks have the potential of being hydrocarbon reservoirs. In many cases, reservoir properties are created by rock-altering physico-chemical processes occurring in the near-surface environment. Hydrocarbon reservoirs in altered granitoids may comprise both arenaceous (clay-poor) and argillaceous (clay-rich) palaeoregoliths, and hence outcrop analogues from various environments are required. In the Sila Massif, southern Italy, the arenaceous weathering of medium to coarse grained granodioritic rocks has been studied. The pore system, dominated by microfractures, was described and quantified at each stage in the weathering process (altered coherent rock facies → saprock facies→ lower and upper saprolite facies → soil) in relation to changes in chemical and physical properties. The transformation of rock to saprolite was close to an isochemical process, as demonstrated by the low variations in the bulk mass transfer coefficient (τbulk). At the same time, trans-, intra- and intermineral microfractures increased in frequency and aperture upwards through the regolith profile. It was the main reason for the reduction of bulk densities (ρb) from 2.66 g/cm3 in the altered coherent rock to 1.88 g/cm3 in the saprolite, corresponding to the formation of up to 30% porosity (φc). The results suggest that a volume increase of >50%, represented by the volumetric strain factor (ε), was the main cause for the transformation of solid crystalline rock to porous saprolite. Anisovolumetric arenaceous regoliths with minimal mass loss, are the result of one of the major weathering processes, notwithstanding that they are much less understood than isovolumetric, anisochemical, argillaceous regoliths. Arenaceous saprolites potentially can have excellent porosity and permeability properties, with open and well-connected microfractures. Reservoir quality of arenaceous saprolites is in stark contrast to the poor permeability observed in some argillaceous saprolites where porosity is dominated by isolated dissolution voids within a clay-rich matrix.

Rare earth elements (REEs) are a group of elements (from La to Lu) with high economic value and serve mainly as essential raw material for various high-technology items. This study explores mineral weathering and the geochemical evolution of regoliths (quaternary period) derived from orthogneisses (late Cretaceous Period) in four sites in Borborema Province, NE Brazil, providing a new contribution to the understanding of the influence of soil and saprolite attributes on the distribution of REEs in the regolith. We used optical and electron microscopy to depict the weathering of minerals in the rock, saprolite and soil microstructure, focusing on the distribution of REEs in the regolith (Depth: 3.0 m). We also determined the poorly and well-crystallized iron oxide contents, the clay fraction amount and the total organic carbon content to observe how these attributes influence the distribution of REEs in the soil and saprolite. The results allowed the classification of weathering for feldspars, micas and other primary minerals into four stages based on their degree of alteration and the consequent influence on the geochemistry of the regoliths. Advancement of the weathering stages revealed the relative increases in Fe and Ti compared with Ca, Mg, Na and K from the fresh rock up to the soil horizons, and ilmenite and xenotime were the main sources of Yb, Y, Co and P. The patterns of signatures and anomalies were different for light (LREEs), middle (MREEs) and heavy rare earth elements (HREEs) and for regoliths in different metamorphic complexes. The LREEs related well with the clay fraction amount, the poorly crystallized iron oxides and the degree of weathering, as estimated by the mineralogical index of alteration (MIA), while the HREEs related well with the total organic carbon (TOC). In particular, Ce was strongly associated with Mn oxides, possibly due to simultaneous oxidative precipitation.

The purpose of this work is to study the weathering processes of the granulite rocks of the Serre Massif (southern Calabria, Italy) using a multidisciplinary approach based on field studies, geochemical modeling, and minero-petrographical analyses. The granulite rocks are plagioclase-rich with minor amphibole, clinopyroxene, orthopyroxene, biotite, and garnet and their texture are coarse-grained. The reaction path modeling was performed to simulate the evolution of groundwaters upon interaction with local granulite by means of the software package EQ3/6, version 8.0a. Simulations were performed in kinetic (time) mode under a closed system at a constant temperature of 11.5°C, (which reproduces the average temperature of local area) and fixing the fugacity of CO2 at 10–2.34 bar (mean value). During the most advanced stage of weathering the main mineralogical changes are: partial destruction and transformation of biotite and plagioclase associated with neoformation of ferruginous products and secondary clay minerals producing a change in the origin rock fabric. The secondary solid phases observed during the geochemical modeling (kaolinite, vermiculite and ferrihydrite) are similar to those found in this natural system. Thus, the soil-like material mainly characterized by mostly sand to gravel grain-size fractions is the final result of the weathering processes.

This study investigates the composition, tectonic setting and age of source rocks of the Mesozoic Kutch Basin, along with the extent of weathering based on heavy mineral characteristics and geochemical investigations. The Mesozoic succession, divided into Jhurio, Jhumara, Jhuran and Bhuj formations, preserves sediments deposited in the Kutch Basin from the Late Triassic to Early Cretaceous. Subangular and subrounded heavy minerals indicate mixing of first cycle and recycled input in these samples. Major oxide ratios such as SiO2/Al2O3, Al2O3/TiO2, K2O/Na2O and trace elements like Zr, Th, Sc, Th/Co, Th/Sc and La/Sc indicate dominantly felsic source. LREE enrichments and negative Eu anomalies support the predominance of felsic source rocks. The V and Ni concentrations in these sediments indicate the input from mafic sources in the older Jhurio and Jhumara formations. Weathering indices such as CIA, PIA and CIW suggest the relatively greater extent of chemical alteration for Jhumara, Jhuran and Bhuj formations in comparison to Jhurio Formation. The higher content of Hf in Jhuran and Bhuj formations suggests the input from older source rocks in younger formations, indicating erosional unroofing at the source. The concentration of Cr and Ni and ratios of Eu/Eu* and (GdN/YbN) indicate predominantly post-Archean source with inputs from older Archean rocks in younger Jhuran and Bhuj formations, and corroborate the erosional unroofing. These evidences relate possible sources of Mesozoic sediments in the Kutch Basin to Precambrian rocks of the Aravalli craton and Nagar Parkar igneous complex.

This study presents physical, petrographical and mineralogical investigation of interbasaltic red bole within the late Cretaceous Deccan lava flows in Pune and Mahabaleshwar areas (India) to understand depositional and weathering conditions. The micromorphological study of red boles reveals two genetic types characterized by distinct features. The first variety, with general sharp lower and upper contacts, consisting predominantly of altered basaltic fragments and volcanic glasses along with hematite, plagioclase, pyroxene (mainly augite), accessory olivine replaced by iddingsite, zircon, quartz, Fe–Ti opaque phases (ilmenite and magnetite), represents a volcaniclastic bole bed. The second variety of red bole, with gradational lower contact and sharp upper contact, containing basaltic clasts, alteromorphs/iddingsite, abundant zeolite and glaebules in groundmass of homogeneous, red, ferruginous clay, is classified as a volcanic paleosol. They are devoid of olivine and pyroxene, with rare alteromorphs of glass. The clay mineral content of red boles was investigated using XRD and VNIR. The presence of 2.21, 2.24 and 2.29 µm absorption features in reflectance spectra of VNIR spectroscopy indicates a mixture of Al-smectite (montmorillonite) and Fe-smectite as the clay mineral constituents, which is confirmed by the XRD data. The presence of smectite and hematite in both types of red boles suggest their formation under near-neutral pH, poorly-drained and moderate weathering condition. Hematite in the red bole suggests a combination of oxidative weathering and the effect of post-burial diagenesis. The volcaniclastic red boles with partially to unaltered mafic minerals and glass shards possibly indicates limited subaerial/subaqueous alteration under oxic condition. The paleosol type red boles with pedogenic features indicate prolonged sub-aerial weathering of flow top basalt, indicating significant hiatus in Deccan volcanism. Zeolite and other alteration products possibly indicate hydrothermal alteration on red bole.

This paper presents the results of a laboratory experimentation carried out on stone materials in the framework of the CRATI project (Knowledge and Restoration through Advanced Integrated Technologies) aimed at testing new products with consolidating properties by means of an integrated methodological approach. After the preliminary characterization of stone materials collected in the pilot site, the second stage of the activities within the project were focused on the formulation and testing of products for the conservation of the same materials against decay, especially salt crystallization, one of the most aggressive and common degrading processes. The San Domenico Church, located in the old town of Cosenza (Calabria, Southern Italy) has been chosen as the pilot site and for the in situ tests. Several specimens with the same features of the stone materials used in San Domenico church were collected from a historical quarry near the city of Cosenza. These specimens were treated and then artificially degraded by salt crystallization tests in order to evaluate their susceptibility to weathering intensity. Three different consolidating products were used, respectively, two commercial and another one formulated in laboratory: (a) a suspension of nanosilica (Nano Estel&reg, ), (b) a suspension of nanolime (CaLoSiL&reg, ), and (c) a suspension of nano calcium-hydroxide dispersed in isopropyl alcohol and then mixed with diammonium hydrogen phosphate. A systematic approach, including minero-petrographic, geochemical and physico-mechanical techniques, was applied to evaluate (a) the nature and main features of materials, (b) the efficacy of consolidating treatments, and (c) the resistance of treated stone to the salt crystallization processes. The tested products demonstrated a significant efficiency to consolidate and protect stone material samples, enhancing their resistance to salt crystallization. Thus, such a case history may be useful in order to plan appropriate restoration interventions that consider the interactions between the building stone and the protective/consolidating product.

Green authigenic mica, i.e., celadonite, is commonly associated with submarine alteration of basic igneous rock. However, very few studies have reported the formation of celadonite under nonmarine conditions. An integrated study involving field investigation, petrography, mineralogy, and mineral chemistry highlighted the origin of celadonite in two clay-rich horizons (green boles) of the Late Cretaceous Deccan volcanic province. Within the Salher green bole, the celadonite occurred as the dissolution and alteration of plagioclase, volcanic glass, and pore-filling cement. In the case of the Pune green bole, the celadonite was formed by the alteration of plagioclase, pyroxene, and precipitation as film within intergranular pores, along with zeolite. The celadonite in the Salher green bole exhibited slightly lower K2O and Fe2O3 and higher Al2O3 than in the Pune. The mineral chemistry of the former showed a composition closer to ferro-aluminoceladonite. Although the mineral chemistry of celadonite overlaps with glauconite, the distinct 10 Å and 15 Å reflections in XRD, euhedral lath and honeycomb morphology under SEM, and characteristic absorption bands in VNIR spectroscopy (0.4–2.5 µm) and FTIR spectroscopy (400–4000 cm−1) identified celadonite and Fe-smectite within green boles. The green boles were formed either by the alteration of a volcaniclastic deposit in local pools of water or by the in situ alteration of the fragmentary flow top. The present study is significant due to the occurrence of celadonite in a nonmarine environment, as it otherwise forms under submarine conditions.

This work focuses on the textural characterization of modern sand supplied from a volcanic island in the Aeolian Archipelago, with particular attention given to the factors that control grain rounding. Twelve beach sands were collected from hightide berms spaced along Lipari’s accessible coastal perimeter. Point-count data were collected using a petrographic microscope with an automated stepper stage. Changes in grain roundness were assessed to evaluate grain resistance to transport(currents and wave abrasion). A numerical value was assigned to very angular (1), angular (2), sub-angular (3), sub-rounded (4), rounded (5) and well-rounded (6) categories. Analyzed particles are monocrystalline grains of plagioclase (Plag) and pyroxene (Py) and volcanic lithic fragments of Lvl (volcanic lithic with lathwork texture), Lvmi (volcanic lithic with microlitic texture), Lvv (volcanic lithic with vitric texture) and Lvf (volcanic lithic with felsitic texture). The most common roundness category among all the grains from the sampled coastal stretches of Lipari island is 3 (sub-angular, 36,1%), immediately followed by 2 (angular, 28,5%), 4 (sub-rounded, 20,0%), 1 (very angular, 10,1%), 5 (rounded, 4,2%) and lower occurrence of 6 (well rounded, 1,1%). We have also determined that some grain types tend to round more quickly in beach environments, such as plagioclase among the monocrystalline grains and Lvmi among the lithic grains population. Lipari’s beach sands are all better rounded on the eastern side which is the more protected part of the island. Alternatively, the sand grains on the east side of the island have alonger residence time on the beach.

The Campania region (southern Italy) is an excellent area to determine the effects of multiple source lithology (volcanic+sedimentary), climate, weathering, transport anddepositional environment on heavy minerals enrichments in the sandy beaches of the coastline between Pozzuoli and Bacoli, and at the Volturno river-mouth. The heavy mineral (HM) assemblage should reflect the clastic supply from the potassic to ultrapotassic lavas and pyroclastic rocks of the Campania and of the Roman Magmatic provinces (Phlegrean Fields, Roccamonfina volcano), and from the recycling of sedimentary - both carbonate and siliciclastic - terranes of the Apennine thrust belt. Opaque oxides, pyroxene and amphibole assemblage dominates in the beach placers of the Campania shoreline - from Bacoli to Pozzuoli - as well as in the Volturno river mouth sands to the north. Modern heavy minerals assemblages reflect clastic contribution from magmatic source rocks whereas contributionfrom sedimentary terranes - exposed extensively in the Volturno river drainage - provide no recycled heavy minerals to the river-mouth sand. Thus, heavy minerals linked to a provenance from the Apennine thrust belt source rocks result diluted and/or unrecognizable using the only HM approach with respect to the minerals provenance sourced by the potassic volcanic fields of Latium and Campania. Thediverse detrital heavy minerals have been characterized describing major stages of progressive chemical weathering, from unweathered to corroded to etched morphologies, a process - in this case-history - playing a minor role in reducing HM diversity through dissolution of moderately stable mineral species.

Weakening of the rock texture in a saprolite by weathering and further pedoplasmation results in the formation of a porous network and neoformed clays, which are the initial stages of pedogenesis, but the saprolite is likely the least studied compartment of the regolith. In this paper, the genesis of clays and their associated pore system was studied in gneiss saprolites. We investigated the saprolites of three regoliths in the Atlantic Forest Biome in northeast Brazil and used optical and electron microscopy to depict the clay–pore morphology. To assess the mobility of clays, we also determined the amounts of water–dispersible and total clay. The total chemical composition (SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O, K2O, TiO2 and P2O5), exchangeable cations (Al+ 3, Ca+ 2, Mg+ 2, K+ and Na+), available P, capacity for saprolites to exchange cations and secondary forms of iron (Fed and Feo) were also measured. Micromorphological analyses showed that the most frequent pore types were channels and fissures. Channels occurred in the more weathered saprolite layers, which were identified according to the weathering indexes, and the clay–sized minerals found in the saprolite were illite, kaolinite, iron oxides, feldspar and quartz. The weathering of biotite and green hornblende formed an Fe–rich clay, and the weathering of feldspars formed an Al–rich clay. Secondary clays were accumulated at the mineral surfaces, pseudomorphs, clay infillings and clay coatings. The clay coatings are formed by two layers, i.e., the first clay layer was formed by an Fe–rich clay, and the second layer was formed by an Al–rich clay. Peculiar features named “doughnut–shaped holdfasts” were described in the clay cutans. The capacity for saprolites to exchange cations was similar to that in the shallower soils, which was environmentally relevant to the adsorption of plant nutrients, e.g., Ca+ 2, Mg+ 2 and K+, and potentially toxic elements, e.g., Al+ 3.

Vibo Valentia&rsquo, s S. Aloe quarter is an archaeological area which has three beautiful mosaic floors, dated between the centuries I BC and V AD. This work reports the results obtained on 22 glass and stone tesserae collected from the Nereid and Geometric mosaics during a recent restoration of the site. The analyses were carried out through a multi-analytical approach. The petrographic study of the stone tesserae was carried out using polarizing optical microscopy while the geochemical one was conducted using two micro-analytical techniques: the electron probe micro-analyzer with energy-dispersive X-ray spectrometry and a combination of laser ablation with inductively coupled plasma mass spectrometry for determining the major, minor, and trace element concentrations. The research highlights the use of different kinds of stones such as marble, volcanic, and sedimentary rocks. The glasses show the typical soda&ndash, lime&ndash, silica composition indicating the use of natron as a flux. The trace element concentrations prove the use of Pb-antimonates to create yellow glass. The bronze scrap was used to obtain the green color, while cobalt and copper were used to obtain different gradations of blue. These results confirm the high technological level reached by glassmakers in the Imperial Age, thus highlighting the importance of the S. Aloe archeological site.

Geomorphological investigations coupled with sedimentological, petrographical, and SEM analyses allowed to identify, for the first time, a paleo-fixed and inland aeolian dune field in the Gioia Tauro Plain, on the Tyrrhenian side of southern Calabria (southern Italy). The aeolian landforms, extended over an area of 43 km2, are characterized by smoothed and elongated NW-SE trending vegetation-fixed linear dunes, varying in height from a few meters up to 20 m. Forty sand samples were collected from dunes to perform laboratory analyses. Grain size analyses showed that samples are composed of unimodal coarse-grained sands (Mz = 0.820 φ), moderately sorted (σ = 0.862), positively skewed (Sk1 = 0.173) and mesokurtic (KG = 1.115). Petrographic analyses highlighted a composition dominated by quartz and minor feldspars. Modal data, and especially the high F/Q ratio and the Rg:Rs:Rm triangular plot, suggest a plutoniclastic supply from the Aspromonte Massif crystalline source rocks. SEM analyses of sand grains clearly displayed the presence of typical wind-generated features mainly represented by rounded form with low relief, bulbous edges, and dish-shaped depressions. These results combined with morphological analyses showed that these aeolian deposits fall into the category of sand sheets. Furthermore, geological and geoarchaeological data evidenced that dune field was formed in the time interval between ~28 ka and the VI - IV century B.C. The dune filed formation has been interrupted presumably by the combined effect of Holocene tectonics, along the Gioia Tauro-San Ferdinando normal fault, and the lowering of sea level, during the Last Glacial period, originating a natural barrier to windblown sand particles. The findings of the paper will help in understanding both inland aeolian products in southern Europe associated to the second colder phase of the Last Glacial period in the Mediterranean area and the complex patterns of spatial and temporal distribution, as well as the control factors determining preservation of the aeolian sediments throughout the rock record.

This study proposes an integrated methodology which includes pedological, petrographic, mineralogical and geochemical analyses of transparent heavy-minerals, to reconstruct the weathering patterns and pedogenetic processes in a transport-limited erosion regime. Three representative soil profiles developed on crystalline bedrocks, located in Calabria, southern Italy, were studied in detail including the complete weathering profile along the transect bedrock/grus/soil. Differences in the amounts of heavy minerals in each soil profile appear to be controlled by the nature of the local bedrocks. The addition of allochthonous parent material and a varying extent of chemical weathering, likely influenced by topography and duration of pedogenesis. The heavy mineral shapes and surface microtextures, together with the vertical distribution of major and trace elements, the values of the chemical index of alteration and the relative abundance of the clay mineral types along the profiles highlight the different weathering degrees among the profiles. These features are consistent with iron/manganese oxy-hydroxides and clay neogenesis observed on femic heavy minerals. Moreover, they mark a lithological discontinuity between the bedrock and the upper soil horizons, which led to rejuvenation by erosive and colluvial processes along the slopes and/or aeolian deposition of allochthonous material, presumably including a Late Pleistocene to Holocene pyroclastic input. Chemical weathering affecting the majority of heavy minerals is consistent with high rainfall rates, soil moisture availability and acidic pH conditions likely favored by organic acids, prone to chemical reactions and leaching processes. The clay coatings and iron/manganese segregations in the Bt horizons of all the profiles studied suggest that they developed in a warmer humid climate during the interglacial stages of the Pleistocene.

The present work aims to study the behaviour of the protective resin tested on a small portion of sandstone rock along the Rupe di Tropea. The Rupe di Tropea, located on the northern coastal edge of the Capo Vaticano promontory (Southern Calabria, Italy), is characterized by frequent landslide phenomena involving large amounts of detritus related to the weathering processes of arenitic sediments. An experimental resin was used in a small portion (the tested surface) of the arenitic sediments of the Rupe di Tropea, in order to check its behaviour against fast erosion processes during the intervention of slope consolidation in 1998. The study of resin was performed trough laboratory tests and petrographic analysis. The results of analysis shown that the resin type was epoxy resin and it has penetrated the rock to a depth of about 2 mm. The tested surface of the arenitic sediments has shown during the last 17 years a good resistance to erosion with only a slight opacization of the applied resin. However, the tested surface is characterized by higher content of soluble salts then the non-treated surface due to the infiltration of water enriched in soluble salts related to the marine aerosol. In these conditions the soluble salts crystallize in the rock pores and between the prismatic cleavage of the micas producing an increase of physical stress and consequent exfoliation processes of the resin surface layer. After a long period, this produces a rock breakdown when these soluble salts evaporate, leaving salt crystals behind. Thus, the epoxy resin improves the resistance to erosion only in a restricted period and without infiltration of water. Over time the infiltration of moisture may introduce dangerous soluble salts. Thus, if the treated surface is not well isolated from the water infiltration, the resin produces after a long period an increase of the crystallization of the soluble salts with consequent important exfoliation processes of the treated area.

The association among volcanism, tectonics and sedimentation may be critical for interpreting the paleogeographic and plate tectonic settings of the past. In modern and ancient sedimentary systems, volcaniclastic fragment classes have been distinguished on the basis of texture and composition. Criteria adopted for their temporal and spatial correlation with source volcanic areas, in terms of type of volcanism and particle-forming processes are still not well constrained and often a topic of controversy and misinterpretation. Here, we present data for volcaniclastic fragments occurring in modern beach sands of the Campanian coast of southern Italy, where there are two active volcanic areas, the Phlegrean Fields and Mt. Vesuvius. Despite their geographical proximity, these volcanoes are characterized by different magma compositions and eruptive mechanisms. We set out to test whether this translates into different textural and compositional characteristics of their associated volcaniclastic detritus in order to better constrain the criteria relating the type of volcanism to the nature of volcaniclastic sand fragments in the sedimentary record. Along a ~100 km coastal stretch, from the Volturno River mouth to Sorrento, 72 sand samples were collected mainly in beach berm environments. Detrital modes were defined for the medium sand fraction of each sample, where monocrystalline and lithic grains are easily identified. The analyzed samples show a mixed sedimentary and volcanic provenance. Samples from the northernmost coastal stretch show a sedimentary petrofacies at the Volturno River mouth. Bacoli marks the transition between the Apennine sedimentary and Phlegrean volcanic petrofacies. Along the Portici-Sorrento coastal stretch, volcanic lithic fragments dominate. Leucite and sanidine crystal components indicate that detritus from the Phlegrean Fields extends south from Licola to Naples Bay, whereas the Vesuvius provenance extends from Naples/Portici south to Castellammare di Stabia. Phlegrean Fields and Mt. Vesuvius volcaniclastic petrofacies have been discriminated through a different distribution of both compositions of the volcanic lithic fragments, leucite and K-feldspars content. Volcanic lithics with lathwork texture and leucite, are Mt. Vesuvius provenance source sensitive detrital grains, whereas volcanic lithics with vitric texture and K-feldspars marks the transition to the Phlegrean Fields petrofacies. The results formalize three different sandy petrofacies which were mapped from north to south as Sedimentary, Phlegrean (volcanic) and Vesuvius (volcanic) petrofacies.

The pressure to increase biomass production worldwide has pushed the boundaries of agricultural lands towards fragile soils. This process is particularly intense in Pernambuco State, NE Brazil. Pernambuco features a moisture gradient, with soils developed from similar gneisses. Resistant structures within the rock influenced the internal movement and distribution of water, consequently influencing regolith genesis. This paper presents the mineralogical characteristics of three regolith profiles with shallow soils (here assumed to be soils in which the top of the Cr horizon is at a depth of 1.5 m or less) along a transect at 8°S and discusses their weathering and pedogenetic processes. Samples were investigated via optical microscopy and scanning electron microscopy (SEM), X-ray diffraction (XRD) and total chemical analysis by inductively coupled plasma - atomic emission spectrometry (ICP-AES). The presence of weathering-resistant quartz veins and planes in the rock structure played a central role in controlling the water dynamics and the advancement of the weathering front. Therefore, desilication was dominantly controlled by the pore network. Hence, the weathering indexes did not differ appreciably among the climatic zones, and both 1:1- and 2:1-type clays were found in all profiles, although the amount of clay minerals that formed and the degree of dissolution of the primary minerals varied among the climate types. From an agricultural perspective, the thinness of these soil profiles and the presence of leucocratic layers are the main drawbacks of the regoliths, whereas the capacity to supply plant nutrients via primary mineral dissolution near the root zone can be an advantage.

This work focuses on developing multidisciplinary research on weathering profiles of granitoid rocks related to the tectonic and landscape evolution of the Capo Vaticano area, Calabria, southern Italy. During the Pleistocene, the Mediterranean climate plays, on the already decomposed plutonic rocks, important processes of alteration, on both the highest and inland areas and the coastal areas of the Calabrian region, such as the studied area. Field observations coupled to chemical, minero-petrographical features and geochemical modelling are used to characterize the weathering processes affecting the granitoid complex. The granitoid cut slopes show a generally simple weathering profile characterized by a progressive increase in weathering towards the top of the slopes. The completely weathered rocks (class V) and residual soil (class VI) contain a high percentage of altered minerals, microfractures, and voids. The main mineralogical changes are the partial transformation of biotite and the partial destruction of feldspars (mainly plagioclase) that are associated with the neoformation of secondary clay minerals and ferruginous products during the most advanced stage of weathering. These transformations produce a substitution of the original rock fabric. Geochemical modelling showing the precipitation of kaolinite, illite, vermiculite, ferrihydrite and calcite. These secondary solid phases are similar to those found in this natural system. Thus, the final results of the weathering process is a soil-like material mainly characterized by mostly a sand to gravel grain-size fractions related to microfabric changes and mineralogical and chemical variations. Copyright © 2014 John Wiley & Sons, Ltd.

The Messina Strait, situated along the southern sector of the Italian peninsula, provides a good setting to study the source-to-basin relationships and, thus, the complete transect from continental to deep-marine environments. This work concerns the chemical and mineralogical composition of the fine-grained sediments collected along the Messina Strait, since the distribution of major and trace elements related to the mineralogical assemblages allow us the reconstruction of sedimentary evolution and geological processes affecting the studied sediments and, thus, the relationships developed between source area and sedimentary basin. Studied sediments are very-fine sand, silt and clay mainly phyllosilicates and quartz-bearing. Specifically, sediments located on submerged Calabrian and Sicilian slopes generally show high quartz content, whereas samples of the Calabrian and Sicilian continental slopes generally show high phyllosilicates content. Calcite and feldspars (plagioclase and K-feldspar) occur in different amounts. Few samples contain Fe-oxides. The geochemical signatures of the sediments reflect a provenance from felsic lithotypes. The A-CN-K diagram shows a linear trend parallel to A-CN join reflecting, primarily, weathering from granitoid rocks. This trend may result from non-steady state weathering conditions where active tectonism and uplift, as shown by morpho-structural conditions of the Messina Strait and its complex tectonic network, enhance mechanical erosion of mineralogical zones differentiated along weathering profiles developed on source rocks. Weathering efficiency at source area suggests weak intensity, related to a temperate Mediterranean climate similar to that characterizing the present-day study area.

This paper explores the role of five recurrent epilithic lichen species (Aspicilia intermutans (Nyl.) Arnold, Xanthoparmelia pulla (Ach.) O. Blanco, A. Crespo, Elix, D. Hawksw. & Lumbsch, Rhizocarpon lecanorinum Anders, Tephromela atra (Huds.) Hafellner and Lecanora bolcana (Pollini) Poelt), which encrust granodiorite spheroidal boulders exposed in the Sila uplands (Calabria, southern Italy), in weathering of plutonic rocks in a typical mountainous Mediterranean environment. A detailed investigation was carried out on the lichen–rock interface of each species, by comparing them mutually and with lichen-free granodiorite samples. For this purpose, the lichen species were sampled together with the encrusted rock surface for detailed mineral-petrographic analyses performed in thin and ultra-thin sections. Optical and scanning electron microscopy of these sections and of bulk samples permitted us to highlight the peculiar modes of physical and chemical attacks of lichen thalli and hyphae on and into the substratum for each species. Crack systems often parallel to the outer rock surface appear often intruded by hyphae, which cause rupture of primary minerals, with detachment and progressive incorporation of their fragments into the thallus. In particular, the species L. bolcana and T. atra revealed an unexpected, partly endolithic behavior, presumably enhanced by the presence of rock fractures earlier generated by other physical breakage processes already affecting the spheroidal boulders in the Sila mountains. Dissolution features often affect primary minerals (even quartz), that may show very peculiar patterns which are suggestive of a biologically-induced control. Various phyllosilicate clay minerals were identified using SEM–EDS microprobe analyses and FT-IR spectroscopy, which also enabled the identification of possible amorphous silica (or quartz micrograins), rhizocarpic acid and carotenoid at the encrusted granodiorite interface. In contrast, neither oxalic acids nor oxalates were detected.

We have studied the petrography and the bulk-rock geochemistry of arenites and mudstones of the Cenomanian Peruc–Korycany Formation to characterize their provenance and sedimentary history, as well as the influence of weathering, hydraulic sorting, and recycling of the source rocks. The Peruc–Korycany Formation contains sedimentary facies reflecting both meandering- and braided-river systems and shallow-marine systems. Differences in the three depositional settings did not cause distinctly different modifications of the framework compositions of the arenites. The sand from the fluvial systems is very mature (Qm98F0Lt2). These fluvial arenites were subsequently modified by shallow-marine processes; reworking produced very slight decreases in the abundance of lithic fragments and polycrystalline quartz grains. The Cenomanian strata of the Bohemian Cretaceous Basin were derived dominantly from metasedimentary and crystalline rocks of the Palaeozoic Tepla-Barrandian and Cadomian Moldanubian units, respectivel...

Five representative soil profiles outcropping in the area around the Cecita Lake (Calabria, South Italy) were characterised by field work, chemical and mineralogical analyses, optical and scanning electron microscopy. Interactions among weathering, pedogenesis and geomorphic processes are emphasised, in an attempt to link the results obtained at different scales of observation. The important role of topography in controlling soil development or removal by erosive processes is discussed, in relation to the natural geomorphological context and the effects of human pressure. Both present-day and relict features were recognised in the studied soils, and discussed in terms of environmental conditions and climatic changes. The chemical composition of volcanoclastic components identified in some soil horizons with Andosol-like field appearance, coupled with pedogenetic features, contributed useful chronological constraints for the reconstruction of Late Quaternary geomorphic events.

Weathering and soil features in the upland landscapes developed on granitic terrains of the Sila Grande Massif (Calabria, South Italy) have been studied in this work. The attempt to link field scale and micromorphological observations in order to better understand the main weathering processes and their controlling factors is revealed to be very powerful. Six soil profiles in the area around the Cecita Lake, representative of different geomorphological units, were characterised by field work, optical microscopy and SEM-EDS analysis. A strong influence on weathering and pedogenesis by micro-scale features of primary minerals and parent rock fabrics is shown. Key roles are played also by relief, in the development and preservation or stripping of regolith + soil mantles in relation to natural and man-induced phenomena; by time, controlling rates and degree of development of the main weathering features; by climate, in terms of type and intensity of dominant processes.

The Tajo River, the 10th largest river in Europe, drains part of the western passive margin of Europe that includes multiple tectonic elements of the Iberian plate. Modern fluvial sand composition in the Tajo River drainage basin reflects the nature of the source region, which lies in the central part of the Iberian Peninsula. Four fluvial petrographic provinces (A, B, C and D) can be established in the Tajo drainage basin, corresponding well with the four principal structural units drained: (1) the Iberian Range; (2) the Hesperian massif; (3) The Tertiary Tajo basin; and (4) the Neogene Santarem–Lisboa basin. Province A corresponds to the Tajo River head and is characterized by quartzolithic sedimenticlastic sands (Qm67F4Lt29 and Rs79Rg3Rm18). These sands have been derived from diverse Mesozoic siliciclastics and carbonates of the Iberian Range. Province B appears in the upper reaches of the Tajo River course and is quartzofeldspathic (Qm57F34Lt9) with diverse rock fragments (Rs34Rg23Rm43). Sources are Hercynian granitoids and metasediments and Neogene clastics and minor carbonates of the Tertiary Tajo basin. Province C extends along the middle course of the Tajo River with quartzofeldspathic metamorphiclastic sand modes (Qm60F33Lt7; Rs4Rg21Rm75). The sources are metamorphic rocks intruded by plutonites of the Hesperian Massif. Province D is quartzofeldspathic (Qm55F39Lt6) with a dominance of phaneritic rock fragments (Rs5Rg33Rm62) and corresponds to the lower reaches of the Tajo River, where siliciclastic deposits of the Neogene Santarem–Lisboa basin are the main sources. Sands plot on provenance-discrimination diagram (QmFLt) within the recycled-orogen field (Tajo River head) and continentalblock fields (upper, middle and lower course). In addition, we have proven the usefulness of the RsRgRm diagram to discriminate the defined fluvial provinces, originating from heterogeneous parent-rock textures and mineralogy. Climate does not exert any strong influence on the petrogenesis of the Tajo River drainage basin sand, and erosion in the source areas may be described in terms of weathering-limited denudation regime. By contrast, mixing with tributary supplies is the main process that modifies composition in the Tajo River sand. The establishment of fluvial provinces related to the main bedrock structural units reflects the great relevance of tributaries from each province in the generation of the Tajo River sand and the low significance of inherited sandy load from previous provinces. The abundance of granitoid rock fragments (RsRgRm%Rg) in fluvial sand of both tributaries and main channel of the Tajo River drainage basin faithfully represents the relative abundance of granodiorite+monzogranite bedrock exposure in each subbasin. Metasedimentary and metamorphic bedrock outcrop area is overrepresented by metamorphic rock fragments (RsRgRm%Rm) in both sand from tributaries and from the Tajo main trunk river. This is manifested by differences of 18–23% between means of metasedimentary outcrop area and the RsRgRm%Rm mean in the sand from Provinces B and C+D, respectively. Sedimentary (mainly carbonate) outcrop area is underrepresented or not represented by sedimentary rock fragments (RsRgRm%Rs) in sand of the Tajo River. This underrepresentation causes a difference between means of sedimentary outcrop area and the RsRgRm%Rs mean of 21%, 17.1% and 10.7% in sands from Province A, B and C+D, respectively. This fact confirms the rapid loss of these grains during transport because of their labile nature.

The Betic Cordillera of southern Spain represents an uplifted foreland fold–thrust belt. Source rock types of the Betic Cordillera include metamorphic (mainly phyllite, schist, quartzite, and gneiss), sedimentary (siliciclastic and carbonate), volcanic (felsic to intermediate pyroclasts), and mantle-derived (peridotite, gabbro, serpentinite, and serpentine schist) rocks. The fluvial systems range that transect the Betic Cordillera are the major detrital source of sediment along the southern Spanish coast, supplying sand to beaches and offshore depositional systems in the Alboran Sea basin. Three key sand petrofacies derived from the Betic mountain belt reflect the main clastic contribution of known source rocks. All the sands are quartzolithic, ranging from quartz-rich to lithic-rich. Fluvial systems draining the Sierra de Los Filabres, the Sierra Nevada, the Sierra de Gador, and the Ma´laga Mountains, and their related beaches constitute a metamorphic–sedimenticlastic quartzolithic sand petrofacies (Qm34610 F463 Lt6269; Lm72614 Lv264 Ls26613), derived dominantly from the Nevado–Fila´bride, Alpuja´rride, and Mala´guide complexes. This quartzolithic petrofacies extends from northeast of Almeria to Torremolinos (southwest of Ma´laga), and northeast of Algeciras. Only one beach sand sample, east of Cabo de Gata, is volcanolithic. Volcanic detritus (mainly having felsitic textures) is derived from Miocene (15–7 Ma) pyroclastic sequences cropping out in the southeast of the chain. This metamorphic–sedimenticlastic quartzolithic petrofacies changes in the coastal stretch from Torremolinos to Marbella, where drainage systems cut across the Serrania de Ronda. Here source rock types include peridotite, gabbro, and serpentinite of the Ronda Peridotite Massif, and metamorphic rocks of the Ma´laguide and Alpuja´rride units. The fluvial and beach sands of this area are quartzolithic (Qm32612 F1063 Lt58611), and include abundant peridotite and serpentinite grains. The latter quartzolithic petrofacies changes abruptly from Algeciras to Ca´diz, where the sand becomes quartz-rich (Qm7765 F462 Lt1964). This sand petrofacies is derived predominantly from recycling of sedimentary sequences, mainly the quartzarenite turbidite units of the Gibraltar Arc (the Algeciras Flysch). This petrofacies is characterized by higher proportion of quartz grains and abundant sedimentary lithic fragments (Lm163 Lv161 Ls9863). The three onshore petrofacies plot in the recycled-orogen provenance compositional field and the lithic to transitional to quartzose recycled subfields of Dickinson (1985). They vary from lithic, to transitional and quartzose depending on their source lithologies in the Betic foreland fold–thrust belt. These actualistic petrofacies best describe the nature and distribution of sand petrofacies derived from a collisional fold–thrust belt where primary and recycled source rocks are interfingered. Deep-marine turbidites of the Alboran Basin have basinwide quartzolithic sands having close compositional relations with Betic Cordillera onshore sand petrofacies. Comparison of detrital modes from mainland to deep-marine environments provides a suitable basis for interpreting the Miocene to Pleistocene sand dispersal history in the Alboran Basin. These modern quartzolithic petrofacies are used to interpret analogous ancient collisional sandstone petrofacies of the Alpine orogenic belt of the western-central Mediterranean region and of other collisional orogenic systems, as a broader point of view.

Plutonic and gneissic rocks of the Sila Massif in the uppermost portion of the Neto drainage basin (Calabria, Southern Italy) weather and erode under a humid Mediterranean climate. During the development of weathering pro®les, a combination of chemical weathering and granular disintegration processes occurred. Chemical weathering involves a loss of both plagioclase (mainly during grus generation) and K-feldspar (mainly during soil formation). This loss is attributed to transformation of plagioclase to clay minerals and to leaching and dissolution of K-feldspar. Sand composition is quartzofeldspathic and nearly homogeneous along the main channel of the Neto River, even where the river cuts across a blanket of sedimentary cover. Thus, ¯uvial transport does not alter sand composition within the Neto drainage basin. Petrographic indices are effective in (1) discriminating between contributions from similar (granite and gneiss) source rocks (Qm/F); (2) relating the provenance of plutoniclastic and gneissiclastic sand found in the headwaters to grus horizons (Qm/F; Q/Rg); and (3) distinguishing between upstream ®rst-cycle and downstream multicycle sand (Q/Rg). This last distinction is further emphasized by considering both aphanitic and phaneritic varieties of rock fragments (RgRmRs diagram). Chemical weathering is the main sand producer within the regolithic environment in northern Calabria. In addition, rapid erosion resulting from steep slopes removes weathered products, and rapid and short transport leads to minimal sediment maturation. In general, the F/Q index is climate and relief dependent; thus, it should be used in conjunction with palaeoclimatic and palaeophysiographic evidence for provenance interpretations of ancient quartzofeldspathic sandstones.

The effects of weathering in a Mediterranean climate on the mineralogy and microfabric of Paleozoic gneiss of the Sila Massif, Calabria, southern Italy, have been studied. Field observations show highly weathered rock forms a residual soil. Micromorphological and mineralogical properties of bedrock and saprolite show that the weathering process is characterized by at least two major stages, having two distinct rock microfabrics. In the first stage, the morphological features of the original rock are preserved and weathering is manifested mainly by microfracturing, and large portions of the rock remain unaltered. The second stage of weathering involves further development of microcracks and progressive chemical attack on the minerals. This latter stage occurs along both compositional and microstructural discontinuities, with etch pitting of feldspar, and neoformation of clay minerals and ferruginous products replacing feldspar, biotite, and iron-bearing garnet. The determination of quantitative petrographic indices provides a measure of the various stages of weathering.

Deeply weathered plutonic rocks occur widely in the Sila Massif, Calabria, southern Italy. Three representative weathering profiles developed on the hilltops indicate that sand represents more than 50% by weight throughout most of the weathering profile, and silt- and clay-size fractions are also well represented, filling the interstices among corestones. Both sand, and finer fractions of grus, and soil horizons, are thought to be derived from a combination of granular disintegration and chemical decomposition, developed on relatively flat terrains of the Sila massif. These slopes are now experiencing transport-limited morphodynamics, under a montane-modified Mediterranean climate. The depth of the weathered layers, that have suffered little erosional truncation, typically exceed 15 m, and may reach 50–60 m or more. Major isolated or grouped exfoliation boulders are the most common minor landform feature developed on the Sila massif granite. Boulders have developed as a result of spheroidal weathering and by removal of the sandy-textured granite. The Schmidt hammer (SH) test on boulders and corestones, suggests three distinctive degree of weathering (from moderately to completely weathered rock), and that biotite content is the major controlling factor of the granite mechanical behaviour. Understanding of the dynamics of this weathering system is crucial to the interpretation of the complex suite of variables that control landscape evolution of granitoid terrains.

Source rock lithology and immediate modifying processes, such as chemical weathering and mechanical erosion, are primary controls on fluvial sediment supply. Sand composition and Chemical Index of Alteration (CIA) of parent rocks, soil and fluvial sand of the Savuto River watershed, Calabria (Italy), were used to evaluate the modifications of source rocks through different sections of the basin, characterized by different geomorphic processes, in a sub-humid Mediterranean climate. The headwaters, with gentle topography, produce a coarse-grained sediment load derived from deeply weathered gneiss, having sand of quartzofeldspathic composition, compositionally very different from in situ degraded bedrock. Maximum estimated CIA values suggest that source rock has been affected significantly by weathering, and it testifies to a climatic threshold on the destruction of the bedrock. The mid-course has steeper slopes and a deeply incised valley; bedrock consists of mica-schist and phyllite with a very thin regolith, which provides large cobble to very coarse sand sediments to the main channel. Slope instability, with an areal incidence of over 40 per cent, largely supplies detritus to the main channel. Sand-sized detritus of soil and fluvial sand is lithic. Estimated CIA value testifies to a significant weathering of the bedrock too, even if in this part of the drainage basin steeper slopes allow erosion to exceed chemical weathering. The lower course has a braided pattern and sediment load is coarse to medium–fine grained. The river cuts across Palaeozoic crystalline rocks and Miocene siliciclastic deposits. Sand-sized detritus, contributed from these rocks and homogenized by transport processes, has been found in the quartzolithic distal samples. Field and laboratory evidence indicates that landscape development was the result of extensive weathering during the last postglacial temperature maximum in the headwaters, and of mass-failure and fluvial erosional processes in the mid- and low course. Copyright © 2000 John Wiley & Sons, Ltd.

Alluvial fans are widespread throughout Calabria, but only a minority display evidence of current activity. In order to understand if and to what extent fan types and their morphology are dependent on the physical environment, including characteristics and processes of the depositional site and drainage basin, we performed a series of discriminant analyses. These analyses used as classification factors the presence or absence of fill in the feeder channel, conditions of confinement by host terrain, the dominant depositional process (debris-flow or sheetflood); and morphometric attributes of fans and drainage basins as the discriminant function variables. in general, fan slope, area and width-length ratio, and, for basins, Melton's ruggedness number and source ratio, were the most useful variables for classification. Best results were obtained by discriminating the types of fan deposits and the presence versus absence of fill in the feeder channel, if the feeder source is singular. Fan morphology is controlled by constructional processes and is tightly linked to basin morphology. On the other hand, fan and basin morphology are also strongly dependent on the rock mechanical characteristics, with hard rocks imparting to the basin a high ruggedness and to fans a high gradient. Larger fans, however, are those where sheetflooding predominates. Results of discriminant analysis based on fan and basin variables are much more significant than those based on fan variables only. This means that the differences between characteristics of fan-and-basin systems are better defined than those between characteristics of fans only. (C) 1998 Elsevier Science B.V. All rights reserved.

The composition as well as stratigraphic and structural relations of sandstone and sand derived from erosion of the Calabrian Arc provide constraints for paleogeographic and tectonic models of southern Italy. Clastic detritus in the following sedimentary assemblages was derived mainly from provenance terranes within the strongly deformed Calabrian Arc allochthon: (1) the Paleogene Liguride Complex accretionary wedge, deposited in a remnant ocean basin that lay east of the Calabrian Arc and west of the Adria margin; (2) Burdigalian to lower Messinian foreland basin successions, widely developed in the southern Apennines, representing progressively shifted foredeep basins and related wedgetop basins; (3) upper Tortonian to Messinian, mainly nonmarine to shallow-marine successions, cropping out in the western Calabrian Arc, representing synrift clastic wedges related to backarc rifting in the Tyrrhenian area; and (4) the Quaternary of the northern Calabrian Arc, represented by foredeep and related wedgetop b...

The Transverse Ranges of southern California represent an uplifted and variably dissected Mesozoic magmatic arc, and Mesozoic to Holocene sedimentary and volcanic strata deposited in convergent and transform tectonic settings. Modern sand within part of the Western Transverse Ranges represents: first-order sampling scale of the Santa Monica and the San Gabriel Mountains; second-order sampling scale of the Santa Clara River draining both mountain ranges; and third-order sampling scale of the beach system between the mouth of the Santa Clara River and the eastern Santa Monica Mountains, and turbidite sand of the Hueneme-Mugu submarine fan. Source lithology includes plutonic and metamorphic rocks of the San Gabriel Mountains, and sedimentary and volcanic rocks of the Santa Monica Mountains. First-order sands have large compositional variability. Sand from local coastal drainage of the Santa Monica Mountains ranges from basaltic feldspatholithic to quartzofeldspathic. Sand of the San Gabriel Mountains local drainages has three distinct petrofacies, ranging from metamorphiclastic feldspatholithic to mixed metamorphi/plutoniclastic and plutoniclastic quartzofeldspathic. Second-order sand is represented by the main channel of the Santa Clara River; the sand has an abrupt downstream compositional change, from feldspathic to quartzofeldspathic. Third-order sand (beaches and deep-sea turbidite samples) of the Santa Monica Basin is quartzofeldspathic. Beach sand is more quartz-rich than is Santa Clara river sand, whereas turbidite sand is more feldspar-rich than is beach sand. Deep-sea sand has intermediate composition with respect to second-order samples of the Santa Clara River and third-order samples of the beach system, suggesting that (1) the Santa Clara River is the main source of sediments to the marine environment; and (2) local entry points from canyons located near local drainages may generate turbidity currents during exceptional flood conditions. Petrologic data of modern sand of the study area are highly variable at first- and second-order scale, whereas third-order sand is homogenized. The homogenized composition of deep-marine sand is similar to the composition of most ancient sandstone derived primarily from the Mesozoic dissected magmatic arc of southern California. This study of the Western Transverse Ranges illustrates the effects of source lithology, transport, depositional environment, and sampling scale on sand composition of a complex system, which provides insights regarding actualistic petrofacies models.

The northern Tyrrhenian margin of Calabria in southern Italy provides a natural laboratory for sampling sand at different scales: small drainages (first order), rivers draining mountain ranges (second order), and marine environments (beach to deep-marine; third order). Calabrian mountain ranges represent an uplifted and variable dissected thrust belt constituted by Palaeozoic through Pleistocene plutonic, metamorphic, ophiolitic, carbonate and siliciclastic rocks. The modern setting includes a mountainous coast, having high rates of fluvial discharge, and the deep-marine Paola Basin. The composition of modern fluvial and beach sands is useful for the interpretation of sediment transported into deeper-water environments. Modern beach and fluvial sands of the northern Tyrrhenian margin of Calabria define three distinct petrologic provinces, from north to the south: (1) the Lao Littoral Province has calclithite sand derived from erosion of dominantly carbonates of the southern Apennines; (2) the Coastal Range Littoral Province has quartzolithic sand derived from dominantly metamorphic (schist and phyllite) Coastal Range; and (3) the Santa Eufemia Littoral Province has quarzofeldspathic sand derived from dominantly metamorphic Coastal Range and Sila Massif and plutono-metamorphic Mount Poro provenances. Deep-marine turbidites of the Paola Basin have basinwide quartzolithic turbidite sands having close compositional relations with Coastal Range littoral petrofacies. Only at the northern boundary of the Paola Basin, calclithite turbidite sand record deep-water dispersal of the Lao littoral sands. Comparison of detrital modes from mainland to deep-marine environments contribute to the models of dispersal pathways and geographical extension of actualistic sand petrofacies.

The composition of sandstones derived from erosion of the southern Apennines orogen provides constraints for Cenozoic tectonic evolution. Clastic wedges were derived mainly from the strongly deformed Calabrian arc allochthon. This key tectonic element is interpreted as a thrust sheet of European crust, moved about 300-400 km eastward during the Paleogene to Neogene toward the Adria foreland. During the Paleogene to Early Miocene, the Liguride Complex oceanic terrane was deposited in a remnant ocean basin, east of the Calabrian arc, related to northwestward subduction of Ligurian oceanic lithosphere beneath the European margin. Upper Paleogene quartzofeldspathic and volcanolithic Liguride sandstones testify to provenance from the subduction complex to the magmatic arc, respectively. Upper Oligocene to lower Miocene quartzolithic sandstone suggests a recycled-orogen provenance (i.e., metasedimentary rocks in the growing accretionary Calabrian arc). Final closure of the Liguride remnant ocean basin and onset...

The Cilento Group (Lower-Middle Miocene), the Monte Sacro Conglomerate (Upper Miocene), the Gorgoglione Formation (Upper Miocene), and the Crati submarine fan (Holocene) are four turbidite sequences deposited in northwest-southeast-trending thrust-top basins of the southern Apennines (Italy) foreland region. The Corigliano basin is a part of the modern Taranto Gulf foredeep basin that developed since the late Pleistocene. Sandstone detrital modes of the Miocene turbidite units are quartzofeldspathic (Petrofacies 1, 2a, 4, 5, 8; Q62F25L13), quartzolithic (Petrofacies 2b; Q60F16L24), and arkosic (Petrofacies 7; Q50F45L5, reflecting a collisional orogenic provenance. Volcanolithic sandstones (Petrofacies 3, Q23F11L66) suggest an important contribution also from a volcanic source area related to the convergent-continental-margin volcanism connected with the collisional tectonic regime that affected the western Mediterranean (e.g., Sardinia volcanic arc). Individual carbonatoclastic beds (hybrid arenite, biocalcarenite, and mudstone) are interbedded with sandstone units of the ilento Group. They have siliciclastic content of about 35% and are quartzofeldspathic (Petrofacies 6; Q53F23L24). These beds (0.10-65 m thick) record impulsive gravitational collapses of the carbonate-platform passive margin to the east and southeast. The petrologic parameters show a temporal evolution from metasedimentary to granitic-gneissic provenance ascribed to different tectonostratigraphic units of the Calabrian arc. Nine Miocene petrofacies suggest dynamic evolution of the source terranes from Laughian to Tortonian time. Facies, dispersal patterns, and petrologic parameters of the Miocene sandstones suggest a provenance from the northern and western margins of the basins. Comparison between the Holocene Crati Fan (Petrofacies 9; Q54F24L22) and Miocene detrital modes suggests that the sandstones of the Cilento Group, the Monte Sacro Conglomerate, and the Gorgoglione Formation were derived from unroofing of the thrusted basement block, transported by torrential-type, fluvio-deltaic systems and then funneled into a major turbidite dispersal system, analogous to the modern Crati submarine fan of the Corigliano thrust-top basin.

During the Messinian, the southern Apennines thrust belt experienced a period of strong tectonic rearrangement and accretion, activation of overthrusts, and consequent migration of depocenters. The upper Miocene successions cropping out in the northern segment of the southern Apennine thrust belt have good potential for improving our understanding of the interplay between Messinian salinity-crisis events and foreland-basin evolution. The local Messinian stratigraphy includes: (1) pre-evaporitic thin-bedded euxinic marly clay, interbedded with diatomaceous marls; (2) evaporitic limestone, crystalline gypsum, and reworked gypsum; (3) post-evaporitic deposits subdivided into two main units: the Torrente Fiumarella unit and the Anzano Molasse Formation that grade upward into ostracod-rich deposits (Lago-Mare facies). The evaporitic and post-evaporitic sequences are separated by an angular unconformity. This paper deals with the stratigraphic and petrographic study of the post-evaporitic deposits. The Torrente...