Options
Salvatore, Maria Cristina
Loading...
Preferred name
Salvatore, Maria Cristina
5 results
Now showing 1 - 5 of 5
- PublicationRestrictedGPR versus Geoarchaeological Findings in a Complex Archaeological Site (Badia Pozzeveri, Italy)The results of a Ground-penetrating radar (GPR) survey were compared with the archaeological excavation outcomes of a twelfth century abbey site (Badia Pozzeveri). The goal was to associate the types of reflections recorded in GPR profiles and high-amplitude features visible in amplitude maps with unearthed archaeological features. GPR profiles crossing the walls evidenced axes of hyperbolic point source reflections and short planar reflections respectively generated by the stones forming the lateral sides/upper corners and the top of the structure. Moreover, the stones in the core of the wall caused small hyperbolic point source reflections with interfering axes, which produced a chaotic reflection profile. The resampling and gridding of these reflections collectively generated high-amplitude linear features in the amplitude maps. The presence in the graves of bones generates small hyperbolic point source reflections with interfering axes in the GPR profile, with a consequently chaotic reflection profile. Moreover, the existence of lythic slabs topping and/or siding the graves generates short planar reflections and axes of hyperbolic point source reflections. The resampling and gridding of these types of reflections generates in the amplitude map features that cannot be locally distinguished from those caused by the local aggregation of sediments with no archaeological relevance. The GPR profiles crossing trenches and pit-kiln showed dipping reflectors unconformably resting on a basal planar reflector. Disconformity marks the onset of trench and pit-kiln decommissioning with the infilling of clayey silty layers and anthropogenic remains. These features in the amplitude maps correspond to medium to high-amplitude areas. The results show that types of reflection can be associated to specific elements of archaeological structure for a detailed interpretation of a complex subsurface setting. Furthermore, it is evidenced that the interpretation of GPR profiles must be considered an indispensable pre-requisite for a full comprehension of amplitude maps
90 1 - PublicationRestrictedChallenges in relative sea-level change assessment highlighted through a case study: The central coast of Atlantic Patagonia(2019)
; ; ; ; ; ; ; ; ; ; ; ; ; There are areas in the world where our understanding of past sea-level changes is less robust than in others. This is partly due to the difficulty past investigators had adopting i) high-resolution elevation measurement techniques (largely available only in the last decade) and ii) standardized methodological approaches to reconstruct past relative sea levels starting from field measurements. The central coast of Atlantic Patagonia (Argentina), preserves a unique succession of coastal landforms, which scientific investigations suggest to have been formed discontinuously since at least marine isotope stage 11 up to the Holocene. Patagonian coastal deposits (in particular raised beach ridges, marine terraces and river mouth terraces) and erosional landforms (slope angles, marine notches) were studied in the past with the aim of reconstructing relative sea-level changes and provide geological evidence to constrain geophysically based models for an area affected by significant vertical displacement due to isostatic adjustment and possibly by tectonic uplift. So far, there is no general agreement about the interpretation of Patagonia landforms and deposits in terms of sea-level index points. This is certainly a gap within a planetary scale overview of sea-level change and represents an obstacle for the construction of a sound model of glacial isostatic adjustment for the area. In this paper we critically analyse previous works on sea-level change along the central coast of Atlantic Patagonia and highlight the major sources of uncertainty, including choices about calculating past relative sea levels from the elevation of indicators and the vertical datum used. We also provide a comparison between different vertical datums (tidal, gravimetric and geodetic) at a real site (Puerto Deseado) where Differential Global Positioning System measurements were performed by our team in 2016, and address the problem from a trans-disciplinary point of view. In order to obtain accurate sea-level change estimates in the area, we suggest the use of a large spectrum of sea-level markers with well-defined indicative meanings and the adoption of specific technical choices capable of minimizing instrumental errors.198 2 - PublicationOpen AccessGeochemical characteristics of the infilling of ground wedges at Puerto Deseado (Santa Cruz, Argentina): palaeoenvironmental and chronological implications(2018)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ;Ground wedge structures of cryogenic origin are common in the Quaternary sediments along the coast of the Patagonia, and their formation is related to climatic cold events experienced by this area in the Late Quaternary. The infilling sediments of two wedges generations were analyzed in the area of Puerto Deseado. Bulk chemistry (major elements), X-ray diffraction (XRD), morphoscopic observations with Scanning Electronic Microscope (SEM) and chemical analyses of volcanic glass shards were undertaken to provide indications about infilling sediment provenience, along with chronological constraint for wedge formation. Bulk chemistry and XRD patterns indicate a significant SiO2- enriched composition of the sediment infilling compared to the most of the loess deposits of the North Argentina and the present day dust originated in Patagonia. This was interpreted as due to the nature of the bedrock present over the Deseado Massif. SEM morphoscopic characteristics of glass shards evidence typical aeolian reworking features, with impact structures and indented edges of the volcanic fragments. Chemical analyses of the glass shards indicate that they were probably generated by the H0 eruption (17,300-17,400 cal yr BP) of the Hudson volcano. Volcanological data indicate that H0 eruption dispersed toward NE, but volcanic glasses were available for reworking due to a WNW component in the western wind direction. Over the Deseado Massif structural high the glass shards mixed with sediments enriched in SiO2, and were eventually deflated further to SE reaching the present coastal area and infilling the frost cracks. The age of the glass shards (17,300-17,400 cal yr BP) and that of the sandy layer affected by cryogenic structures (14,670±750 yr BP) well constrain to the Late Glacial both wedge generations.136 35 - PublicationRestrictedLast Interglacial sea-level highstand deduced from notches and inner margins of marine terraces at Puerto Deseado, Santa Cruz Province, Argentina(2017)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ;A detailed geomorphological survey was undertaken in the area of Puerto Deseado (Santa Cruz Province, Argentina) to reconstruct the Relative Sea-level (RSL) position during the Last Interglacial highstand. The presence of active and well-preserved abrasive notches and inner margins of terraces related to the MIS5e and to the Holocene, measured with DGPS, allowed to accurately estimate the RSL change from the present to the MIS5e highstand at ca. 21 m. The geomorphological and geochronological analyses support the notion of the presence of a significant regional tectonic uplift in the Atlantic Patagonia, which can be locally estimated at ca. 0.12 mm/yr.102 3 - PublicationRestrictedMid-Holocene relative sea-level changes along Atlantic Patagonia: New data from Camarones, Chubut, Argentina(2018)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ;This paper concerns the relative sea-level changes associated with the Atlantic Patagonian coast derived from sea-level index points whose elevation was determined by a differential global position system (DGPS). Bioencrustations from outcrops located near Camarones, Chubut, Argentina, consist of autochthonous deposits characterized by Austromegabalanus psittacus (Molina, 1782), encrusting acervulinid foraminifera, coralline red algae and bryozoans. The association of the different organisms is interpreted as being associated with an intertidal environment, and they have been used as index points to establish the relative sea-level position. The main conclusion is that the relative sea-level between c. 7000 and 5300 cal. yr BP was in the range of c. 2–4 m a.s.l., with a mean value of c. 3.5 m a.s.l. Our data seem to support the existence of different rates of relative sea-level fall in different sectors of Atlantic Patagonia during the Holocene and highlight the importance of a more precise and accurate relative sea-level estimation by producing new data and revisiting the indicative meaning of most of the indicators so far used in the area.113 2