Mineral chemistry and petrogenetic aspects of the Vico lavas,Roman volcanic region,Italy

A detailed study of the phase chemistry of selected lavas from Vico shows that the “excess silica” in leucite is a significant and widespread crystal-chemical characteristic which may be interpreted in terms of an extended solubility of KAlSi₃O₈ and/or differential loss of potassium from the leucite structure. Plagioclase geothermometer data suggest increasing plagioclase control in the differentiation with decreasing Mg/Mg+Fe²⁺ ratios for the bulk rocks. The pyroxene compositions show moderate amounts of ferri-Tschermak's and Ca-Tschermak's molecules, probably controlled by temperature and compositional variations in the cooling liquids. Both microphenocrystal and late-crystallizing micas correspond to phlogopite compositions throughout the suite. The phase chemistry is discussed in relation to the differentiation of the suite and current petrogenetic models.     

Rockfall hazard assessment along a road in the Sorrento Peninsula,Campania, southern Italy

Rockfalls are common in the steep and vertical slopes of the Campania carbonate massifs and ridges, and frequently represent the main threat to the anthropogenic environment, potentially damaging urban areas, scattered houses, roads, etc. Despite the generally limited volumes involved, the high velocity of movement (from few to tens of metres per second) poses rockfalls among the most dangerous natural hazards to man. Evaluating the rockfall hazard is not an easy task, due to the high number of involved factors, and particularly to the difficulty in determining the properties of the rock mass. In this paper, we illustrate the assessment of the rockfall hazard along a small area of the Sorrento Peninsula (Campania region, southern Italy). Choice of the site was determined by the presence of a road heavily frequented by vehicles. In the area, we have carried out detailed field surveys and software simulations that allow generating simple rockfall hazard maps. Over twenty measurement stations for geo-mechanical characterization of the rock mass have been distributed along a 400-m-long slope of Mount Vico Alvano. Following the internationally established standards for the acquisition of rock mass parameters, the main kinematics have been recognized, and the discontinuity families leading to the different failures identified. After carrying out field experiments by artificially releasing a number of unstable blocks on the rock cliff, the rockfall trajectories along the slope were modelled using 2-D and 3-D programs for rockfall analysis. The results were exploited to evaluate the rockfall hazard along the threatened element at risk.     

Geoarchaeological sea-level proxies from a silted up harbour: A case study of the Roman colony of Luni (northern Tyrrhenian Sea, Italy)

The Luni Plain, which faces the northern Tyrrhenian Sea, underwent major landscape changes over the last 3000 years. The coastline shifted south and west, separating the ruins of the ancient Roman colony of Luni (founded in 177 BC) from the sea by means of a new coastal plain. The precise location of the coastline during the main settlement phase as well as during the city's decline has never been established, although partial and qualitative scenarios have been suggested by various authors. According to these authors, an indentation of the coastline west of the city formed a major water basin, along the shores of which traces of pre-Roman settlements exist; near the city, two minor basins were present, suitable for hosting harbour structures. The city of Luni was famed for its harbour (Portus Lunae), from which the marbles quarried in the Apuan Alps, used to build many of the monuments in Rome, were delivered. The traces of its port, however, are scattered and uncertain.Newly available subsurface data are presented, associated with a revision of unpublished archaeological evidence of the ancient city topography. Progress in palaeoenvironmental reconstructions at Luni has been possible thanks to the collection and analysis of ancient and recent cores, supported by radiocarbon dates, as well as the interpretation of archaeological findings suitable as markers for sea-level recognition. The main environmental changes in the area have been refined: since a few centuries before the colony was founded, the Luni plain had been characterized by a complex architecture of swamps and marshes limited by dune ridges and fluvial sand bars. The positions of these landforms were not fixed, but shifted, mainly depending on the spatial relationship between the coastline and the river mouths.Determining the precise position of the Roman coastline is useful to constrain the area in which archaeological surveys should be concentrated in order to identify the harbour location. Moreover, some of these results have been used to infer altitude constraints on the sea-level position in Roman times: preliminary data are shown for constructing a Late Holocene local sea-level curve in the area.     

Petrogenesis of leucite-bearing lavas in the Roman volcanic Region,Italy

The petrogenesis of leucite-bearing lavas from the Roman Region, Italy, is considered in the light of the petrochemistry and mineralogy of the Sabatini lavas, believed to be transitional between the mafic Alban Hills leucitites and the differentiated Vico and Vulsini suites.The Sabatini leucitites are a close variant of the Alban Hills analogues and are probably related to the same cycle of partial melting in the mantle, The prevalent compositional variation, from leucite-tephrite to leucite-phonolite compositions, conforms to the well-known variation of the Vesbian lavas and is attributed to crystal-liquid processes under a low-pressure volcanic regime. The differentiation trends of both the Sabatini and Vico lavas are related to Sabatini parental leucitite compositions, which interacted with recurrent pulses of leucitite liquid during differentiation in a shallow-level environment.The mineral chemistry of the Sabatini lavas reveals extensive and complex chemical zoning in both early and late-crystallized phases. Among the latter, poikilitic feldspars with exceptionally high Sr content (SrO=2–3% wt.) are reported. Early-crystallized phases, notably feldspars and pyroxene, are xenocrystal and indicate significant contamination of the lavas with disequilibrated mineral compositions. Consequently, genetic considerations based on isotopic data from these lavas are suspect. A review of these data is made and it is proposed that the mantle source material of the Roman Region lavas evolved as an open system under the influence of local concentrations of volatile and other mobile elements (Bailey, 1964, 1972, 1974).     

On the Turtle Remains from the Archaeological Site of Anyaug,Houan

This paper embodies the results of a study of the turtle remainscollected during the systematic excavations on the archaeological site ofAnyang,the old capital of the Shang dynasty (circa 1400-1100 B.C.),started since 1928 by the Institute of History and Philology,AcademiaSinica.     

Crystal Chemistry and Site Configuration of the Clinopyroxene from Leucite-bearing Rocks and Related Genetic Significance: the Sabatini Lavas, Roman Region, Italy

A clinopyroxene suite from leucite–bearing lavas locatedin the Sabatini district of the Roman Volcanic Region has beeninvestigated by single–crystal X–ray diffractionmethods combined with electron probe microanalysis. The main aim of the study was to obtain crystallographic datanecessary to evaluate intracrystaUine order–disorder relationshipsin natural clinopyroxenes and related equilibria–disequilibriaphenomena in different host–rock types. Generally, the polyhedral site configurations of the clinopyroxenesinvestigated are interdependent and follow specific variationtrends related to specific host–rock types. The majorvariations are found in the tetrahedron and the octahedron;while the polyhedron M2 is essentially unchanged and occupiedby(Ca+Na). The degree of Mg–Fe²⁺; ordering in M1–M2, respectively,depends on the configuration of these sites, particularly M2,and is generally lower in late–crystallized (rim) clinopyroxenesthan in the corresponding higher–temperature (core) fromthe same crystals. This is' attributed to configuration relationshipsunfavourable to the Mg–Fe²⁺ ordering and largely dependingon the occupancy of M2. Polygenetic, early–crystallized clinopyroxenes, occasionallywith resorbed margins, indicate crystal-liquid disequilibriarelated to crystal and–or magma mixing processes.     

Archaeological and historiographical implications of recent uplift of the Peloro Peninsula, NE Sicily

In ancient times, the name “Peloro” was used to indicate an anthropic area that gradually developed around the first known human settlement on the Sicilian shore near the Straits of Messina. Since the 5th century BC, historians have documented that numerous naval armadas landed for long periods at Peloro. However, the present-day morphology of the Peloro Cape Peninsula does not have any protected inlet that would offer a location to repair hundreds of ships, as has been documented by historical sources. To address this discrepancy, geomorphologic data were collected and analyzed to verify whether historical documents were consistent with the palaeotopography of the area. This approach is based on the analysis of the morphotectonic evolution of the coastal lowland that resulted from regional uplift over the Quaternary and Holocene. The results indicate that the harbour was located in the basin of the Pantano Piccolo salt marsh, and was large and deep enough to have sheltered up to 320 ships.     

Crystallization conditions of leucite-bearing magmas and their implications on the magmatological evolution of ultrapotassic magmas: the Vico Volcano, Central Italy

Summary Mineral compositions in leucite-bearing and leucite-free rocks from Vico volcano are reported. FeO/MgO partitioning (Kd_ol/liq) between olivine and latite (0.14–0.22), and between olivine and trachyte (0.06–0.10) indicates a lack of equilibrium between mineral and host rock. This suggests that mingling and/or mixing between magmas was a leading process during magmatic differentiation. In addition, a phono-tephrite olivine population with high (0.84) and equilibrium (0.23–0.29) Kd_ol/liq values has been produced by the interaction of differently evolved magmas. Zoning in clinopyroxene and plagioclase from these rocks recorded the same processes. In addition, resorbed quartz xenocrysts with coronas of clinopyroxene microlites indicate that digestion of crustal rocks occurred during the residence of magma in a shallow level reservoir. Increasing Fe coupled with decreasing Ca in diopside crystals from some phonolites, together with the petrographic and trace element data, indicate that polybaric fractional crystallisation also may be involved in the genesis of magmas of the second period of Vico activity. Leucite-free trachybasalts erupted in a late stage contain highly forsteritic olivine phenocrysts (forsterite 84–88 mol.%) in-equilibrium (Kd_ol/liq = 0.24–0.35) with the host rock, which indicate that they did not suffer chemical modification at low pressure. Received November 28, 2000; revised version accepted September 27, 2001     

Oxygen isotope studies of potassic volcanic rocks of the Roman Province,Central Italy

The ¹⁸O/¹⁶O ratios of rocks and coexisting minerals were measured for 93 samples of leucite-bearing lavas, pyroclastics, and related volcanic rocks from the Quaternary Roman Co-Magmatic Province, Italy. The ¹⁸O values were found to generally increase northward in the sequence: Ischia (5.8 to 7.0); Somma-Vesuvius and Phlegrean Fields (7.3 to 8.3); Alban Hills (7.3 to 8.7); M. Sabatini (7.3 to 9.7); Vico Volcano (7.4 to 10.2); and M. Vulsini (8.1 to 11.7). The northward increase in ¹⁸O parallels a similar increase in ⁸⁷Sr/⁸⁶Sr, and these data indicate that the Roman magmas have interacted strongly with high-¹⁸O continental crust. A marked increase in ¹⁸O occurs just north of Rome where the Roman Province begins to overlap the calc-alkaline, oversaturated Tuscan Magmatic Province. Therefore, some of the observed ¹⁸O/¹⁶O and ⁸⁷Sr/⁸⁶Sr enrichments in the Roman magmas may have been facilitated by direct mixing with the high-¹⁸O Tuscan magmas or because the high-¹⁸O country rocks underwent widespread heating during a couple of million years of Tuscan igneous activity. Although many of the Roman magmas underwent fractional crystallization without appreciable change in ¹⁸O, contamination has produced a correlation between ¹⁸O and SiO₂ content at several of the volcanic centers; thus the trachytes are typically higher in ¹⁸O than the undersaturated rocks. The major features of the oxygen isotope data can be explained in terms of a simple two-component mixing model in which one end-member was a primary, strongly undersaturated magma derived from the upper mantle, with ¹⁸O+6, ⁸⁷Sr/⁸⁶Sr0.704 to 0.705, and SiO₂<44wt.%. However, none of the analyzed samples have these values, as they have all been contaminated to some extent. The closest approach is found in some of the leucitepyroxenite ejecta from the Alban Hills. The second end-member, derived from the continental crust, had a variable composition with ¹⁸O+12 to +20, ⁸⁷Sr/⁸⁶Sr0.712 to 0.720, and SiO₂65wt.%, and it mixed in much greater proportions in the volcanoes north of Rome than in those of the Alban Hills or the Naples area. The widespread interactions between the Roman magmas and the continental crust are probably due to (1) the fact that such low-SiO₂ magmas always have a very strong tendency to interact with quartz-bearing rocks of the continental crust, and (2) in Italy, these magmas were emplaced into a tectonically very active area containing poorly consolidated sedimentary rocks, and in the northern part of the belt there had been a prior history of extensive calc-alkaline igneous activity.Publication of the Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, Contribution Number 2501.     

Geochronology and Geomorphology of the Pioneer Archaeological Site,Upper Snake River Plain,Idaho, USA

Pioneer is an open‐air, stratified, multicomponent archaeological site located in the upper Snake River Plain of southeastern Idaho, USA. Block excavations provided an opportunity to contribute to the Late Quaternary geomorphic history of the Big Lost River drainage and provide geochronological context of archaeological components at the site. The stratigraphic sequence is interpreted as reflecting multiple depositional episodes and five soil‐formation periods beginning pre‐7200 cal. yr B.P. and lasting to the historic period. The stratigraphic sequence contains an archaeological component dated to ∼3800 cal. yr B.P. and several other components post‐800 cal. yr B.P. Major site formation processes include fluvial deposition and erosion, pedogenesis (accumulation of secondary carbonates), and bioturbation. Periods of increased deposition at Pioneer and elsewhere along the Big Lost River are inferred to have occurred between ∼8400–6500 cal. yr B.P. and ∼2700–400 cal. yr B.P., potentially related to cooler/wetter episodes of the mid‐to‐late Holocene, including increased precipitation during the Medieval Climatic Anomaly (post‐750 cal. yr B.P.). There is also evidence of a high‐energy erosional event at ∼3800 cal. yr B.P. indicating a large middle Holocene flood. Pioneer provides an example of the archaeological and paleoclimatic value of studying alluvial buried soil stratigraphic sequences in arid environments.     

The geochemistry and petrogenesis of the lavas of the Vulsinian District,Roman province,Central Italy

The Vulsinian lavas are dominated by a suite of undersaturated leucite-bearing basic to intermediate compositions. The remaining lavas are mainly oversaturated and have shoshonitic affinities. One hundred and thirty-five samples have been analysed for major elements and most for 20 trace elements. Twenty-seven lavas have been analysed for REE. They are all perpotassic (for the undersaturated lavas: K₂O/Na₂O=2–8) and have very high LIL element concentrations, (e.g. Rb=400–800 ppm, Th=25–150 ppm, REE/REE_cho=c.200, (LREE/HREE)_cho=c.20) even in the most basic rocks.The undersaturated lavas appear to be interrelated by fractional crystallization of cpx±olivine (from 14 to 11 wt.% CaO), cpx+leu±plg±mica (from 11 to 8 wt.% CaO), cpx+leu+plg+apa+magnetite±mica (from 8 to 5 wt.% CaO), and additional sanidine (or hyalophane)±haüyne (from 5 to 3 wt.% CaO). The saturated lavas and the few slightly undersaturated shoshonite basalts are thought to be evolved from the undersaturated magma(s) by crustal contamination or mixing with silica-rich magmas. The parental Vulsinian magma having: Mg-value=c.73, Cr=300–700 ppm, Ni=100–125 ppm, Sc= 40–50 ppm, Fo_89–92, Di_77–97 approximates a primary, mantle-derived liquid. Enrichment in LIL elements (incl. REE) and LREE/HREE suggest a small degree of partial melting from fertile mantle; whereas the low concentrations of Na, Ti and P suggest larger degrees of partial melting. This indicates that either the primary magma or the parental mantle was metasomatized by a fluid, which previously equilibrated with subducted continental material. This model agrees with published high ¹⁸O, high ⁸⁷Sr/⁸⁶Sr and low ¹⁴³Nd/¹⁴⁴Nd.     

Raw Materials for Archaeological Pottery from the Campania Region of Italy: A Petrophysical Characterization

We performed petrophysical analyses on 34 clayey samples of different geological origin within the Campania region of Italy in order to determine possible sources of raw materials used to produce ancient pottery. Possible raw material sources can be grouped into high‐CaO clays (HCC) and low‐CaO clays (LCC). HCC are mainly represented by more recent (Miocene‐Pleistocene) basinal sediments whereas LCC tend to be associated with basinal, alluvial, and pyroclastic deposits. A chemical comparison between clayey raw materials, modern ceramic replicas, and Campanian archaeological ceramics of several typologies (common ware, cooking ware, fine tableware, amphorae, and bricks) from 8th century B.C. to the Middle Ages (a total of 350 ceramic samples) indicates that HCC were extensively used for common wares and that these were either mixed with temper or levigated. In contrast, most of the LCC were used for the production of cookware. We also analyzed the technological potential of the sampled raw materials, taking into consideration their actual and possible uses. We observed that most HCC deposits were well suited for tableware and amphorae, whereas LCC were better for cookware and some fine tableware.     

The Oldest Evidence for Human Habitation in the Baltic Region: A Preliminary Report on the Chronology and Archaeological Context of the Riadino‐5 Archaeological Site

We report the discovery of the oldest evidence for human presence in the southeastern Baltic Sea region. This paper presents an overview of the Riadino‐5 archaeological site in the lower course of the Šešupė River (Kaliningrad Oblast of Russia) and direct infrared stimulated luminescence (IRSL) ages for the culture‐bearing sediments from the site, which place the time of occupation well within the range of Marine Isotope Stage (MIS) 3 (ca 57–26 ka). Luminescence ages were determined using the multiple‐aliquot additive‐dose technique, applied to sand‐sized potassium feldspar. Four of the six IRSL samples from the site come from the cultural deposits, while two are from the surrounding sediments. The luminescence age of the deposits implies that human occupation of the southeastern Baltic Sea region occurred at least between 50 ka and 44 ka during the first half of MIS 3 and the Middle‐Upper Paleolithic.     

Late Holocene Sea Level Reconstructions Based on Observations of Roman Fish Tanks,Tyrrhenian Coast of Italy

We present estimates for late Holocene relative sea level change along the Tyrrhenian coast of Italy based on morphological characteristics of eight submerged Roman fish tanks (piscinae) constructed between the 1st century B.C. and the 2nd century A.D. Underwater geomorphological features and archaeological remains related to past sea level have been measured and corrected using recorded tidal values. We conclude that local sea level during the Roman period did not exceed 58 ± 5 cm below the present sea level. These results broadly agree with previous observations in the region but contrast with recent analysis that suggests a significantly larger sea level rise during the last 2000 years. Using a glacial isostatic adjustment model, we explain how regional sea level change departs from the eustatic component. Our calculation of relative sea level during the Roman period provides a reference for isolating the long‐wavelength contribution to sea level change from secular sea level rise. Precise determination of sea level rise in the study area improves our understanding of secular, instrumentally observed, variations across the Mediterranean. © 2012 Wiley Periodicals, Inc.     

The primitive lavas of Roccamonfina volcano,Roman region,Italy: new constraints on melting processes and source mineralogy

Within a large collection of lavas from the Roccamonfina volcano are rocks which represent the most mafic samples yet recorded from Roccamonfina and which are amongst the least differentiated lavas found in the Roman co-magmatic region as a whole. These rocks extend both high-K and low-K series to more primitive values. However, petrographic and geochemical considerations rule out a primary origin, and even these mafic samples appear to record the effects of repeated episodes of fractional crystallization and hybridization. Relatively potassic samples from the low-K series are apparently transitional between low-K and high-K series, as previously delineated. However, these intermediate-K samples are not transitional in their Sr isotopic composition, suggesting that there is no continuum between low-K and high-K magma source regions. Rather, the compositional range within the low-K series appears predominantly to reflect variation in the degree of melting of a common mantle source. Analysis of the low-K series data, using an inverse method suggests a source containing amphibole and garnet, and indicates that these phases were consumed during the melting processes responsible for the low-K series magmas. The role of amphibole is further indicated by the association of low K₂O with elevated Rb concentration and, for example, higher Ce/Yb. Such variations are taken to reflect the consumption of high K/Rb amphibole during the initial phase of partial melting.     

Chemical and Mineralogical Signatures of Archaeological Features at the Mailhot‐Curran Iroquoian Site,Eastern Canada

The St. Lawrence Iroquoians built villages in southwestern Quebec (Canada) along the St. Lawrence River. They left behind longhouses, hearths, middens, and storage pits like those discovered at the Mailhot‐Curran archaeological site in Saint‐Anicet. Here, we contrast the properties of Iroquoian features with undisturbed soil to define the chemical and mineralogical signature of hearths, middens, and pits. The native soil has a neutral pH and consists of an Ah horizon overlaying a Bm horizon dominated by quartz and feldspars. In the hearths, ashes are characterized by neoformed calcite and apatite with carbonates, higher total P, and enrichment in amorphous inorganic Al, Fe, and Si. The rubified layer of hearths contain poorly crystallized Fe oxides. The mineralogy of the rubified layer is dominated by authigenetic ankerite, an Fe‐carbonate mineral identified here for the first time in Iroquoian hearths. Middens have the highest organic matter content and contain more organically complexed Al and Fe than the soil. The storage pits have low pH values and carbonate content and contain high levels of amorphous Si and total P. Our work establishes the pedologic signature of three Iroquoian features despite significant alteration of their properties by post‐occupational biogeochemical processes.     

Paleochannels and Patches: A Geoarchaeological Assessment of Silcrete Sources in the Cumberland Plain,Eastern Australia

Although Aboriginal occupation dates to the Pleistocene, silcrete artifacts only begin to dominate archaeological sites found in the Cumberland Plain of western Sydney, eastern Australia, during the mid‐late Holocene. These assemblages routinely include large numbers of backed artifacts. A geoarchaeological survey of five potential silcrete source areas found that silcrete is irregularly distributed along ridgelines within gravel patches that represent paleochannel remnants. Thus, particular parts of the landscape, dictated by the geological history, were more likely to be targeted for stone procurement. The quality of silcrete differs between and within the sources due to variations in grain‐size, degree of silicification, and presence of inclusions/fractures, as well as the destructive influence of bush fires on exposed cobbles, resulting in an overall low abundance of high‐quality silcrete across the Cumberland Plain. Furthermore, a rind or chalky weathering cortex on many cobbles means that testing was required to assess the internal raw material quality. The difficulty in locating suitable raw material for artifact manufacture meant that when good silcrete sources were found, they were heavily targeted. This contextual information provides an essential backdrop in which to understand the archaeology of the Cumberland Plain and broader patterns of landscape use.     

成都平原马街遗址古洪水事件遗存考古发现与研究

2014年5月,对四川成都郫县马街遗址古洪水事件做了调查,该遗址经度为103°55 ′ 39″E,纬度为30°53′37.1″N,遗址海拔为黄海高程499.758m,遗址的2014CPMT1-T2探方中有古代生长在地下的树根1处、冲刷带来的独木舟1处、古树干9处.经光学方法鉴定,其中的古树根和古树木主要是秋枫树(Bis...     

A Geoarchaeological Study of the Middle and Upper Pleistocene Levels at Canteen Kopje,Northern Cape Province,South Africa

Canteen Kopje, situated in the Northern Cape Province of South Africa, has two main archaeological deposits: alluvial gravels and a mantle of overlying fine sediments known locally as the “Hutton Sands.” This paper focuses on the fine sediments, the three industries contained within them, and the interface with the underlying gravels in an attempt to clarify their formation and transformation. A Fauresmith assemblage is found at this interface; it is thus crucial to understand the processes of deposition and modification at this poorly understood boundary. The methods used in this study involved the analysis of artifact depositional (dip and orientation) and spatial data, artifact condition, raw materials, and assemblage size profiles. Data presented document the mixing between the lowest levels of the fine sediments and the underlying alluvial gravels. This study thus provides important contextual information for the Fauresmith industry at Canteen Kopje.     

A Multidisciplinary Approach to Earthquake Research: Implementation of a Geochemical Geographic Information System for the Gargano Site,Southern Italy

A priority task for correct environmental planningis to evaluate Natural Hazards, especially inhighly populated areas. In particular, thoroughinvestigations based on different Earth Sciencetechniques must be addressed for the Seismic HazardAssessment (SHA) in tectonically active areas. Notonly the management but also the multidisciplinaryanalysis of all the SHA-related data sets is bestperformed using a Geographic Information System. In this paper we show how a research-oriented GIS isbuilt and used in a practical case. The GeochemicalGeographic Information System (G²IS) wasdeveloped and applied to the Gargano promontory(southern Italy) in the framework of an EC researchproject, the Geochemical Seismic Zonation (GSZ)Project. This multidisciplinary – multiscalingpowerful tool is described in its structure, updatingprocedures and manipulation techniques. Preliminaryresults are presented on the detection of geochemically active fault zones and theircorrelation with remote sensing data and otherevidences of seismogenic structures.