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Ribolini, Adriano
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Ribolini, Adriano
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Ribolini R.
A. Ribolini
RIBOLINI ADRIANO
RIBOLINI A
ADRIANO RIBOLINI
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14 results
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- PublicationOpen AccessGeomorphology of the topmost part of the Bistra Mountain, Mavrovo Park, North Macedonia(2021)
; ; ; ; ; ; ; ; ; Identification of the remnant traces of paleo-glaciers provides important proxies to understand the response of the environment to rapid climate changes. We present a 1:25,000 scale geomorphological map covering ∼12.5 km2 of the upper part of Mount Bistra (North Macedonia) on the basis of remote sensing analyses and geomorphological surveys. Particular attention is given to the description of glacial and periglacial landforms, to the reconstruction of single glacier shapes and to Equilibrium Line Altitude (ELA) value calculation. The results of the survey and the reconstructed ELAs indicate the occurrence of three glacial phases that led to the formation of frontal and lateral moraines. The age of these phases is tentatively attributed to the Late Pleistocene by comparing these ELAs with those of other Balkan mountains. This map is the first step of a wider project aimed at reconstructing the relation between climate change and geomorphic response in this area.151 39 - PublicationRestrictedNew findings of the Campanian Ignimbrite ash within slope deposits of the Treska valley (former Yugoslav Republic of Macedonia)(2017)
; ; ; ; ; ; ; ; ; ; ;; ;In this paper, we describe the first finding of the Campanian Ignimbrite tephra layer in a subaerial succession in the Former Yugoslav Republic of Macedonia. The tephra is interbedded within slope deposits mixed with colluvial loess. The identification of this fundamental stratigraphic marker is based on major elements. The investigated succession is correlated to lacustrine records from Ohrid and Prespa lakes, several archives of the central and eastern Mediterranean, and mainland Ukraine and Russia. Field observations and correlation with lacustrine records (i.e. pollen) indicate that accumulation of the volcanic ash occurred in a dry environment characterized by low vegetation cover and important wind activity, which promoted loess deposition. The recognition of the Campanian Ignimbrite tephra allows the correlation of the loess sediments to the H4 event, as defined in the North Atlantic event climatic stratigraphy.86 4 - PublicationRestrictedCoastal landscape evolution and sea-level change: a case study from Central Patagonia (Argentina)The coastal fringe of Central Patagonia preserves a unique and spectacular succession of landforms discontinuously formed since MIS 11 up to the Holocene. The study area, stretching from 44° 34′ to 44° 54′ S of latitude, is crucial to analyze the complexity of multitemporal shorelines formation and preservation along the Atlantic coast of South America. We used depositional and erosional landforms to get reliable and well chronologically constrained sea level markers. In particular, multistoried swale infillings, produced by a complex relationship between river discharge and marine activity, were considered the most accurate sea level markers. Palaeo sea level elevation was assessed cross checking evidence obtained from different marker types and considering the original position of each of the measured features with respect to its contemporary sea level. A dedicated field measurement of the markers current elevation was necessary, considering the macrotidal regime that currently affects this coastal area. Literature and new data provide an excellent set of dating, useful to chronologically constrain all the palaeo shorelines that have been identified. On the whole five sea level highstands have confidently been referred to Holocene (maximum transgression peak), MIS 5, 7, 9 and 11. Sea level elevation for each of them was stated respectively at 2.5, 7.5, 10.5, 22.5 and 32.5 m a.s.l., but different error bars and levels of accuracy are assigned to each of these estimates, based on innovative criterions that are widely discussed in the text. Our work enabled us to obtain new, self-consistent values of the last 400 ka uplift rates for this coastal tract and to compare them with those calculated by other authors, suggesting for the investigated time span a moderate coastal uplift.
104 4 - 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 - PublicationRestrictedLate‐pleistocene wedge structures along the patagonian coast (argentina): chronological constraints and palaeo‐environmental implicationsThis paper investigates several wedge structures formed in continental deposits covering marine sediments deposited during MIS 5 along the central Patagonian coast of Argentina. The size and surface microtexture characteristics of the infilling sediments are consistent with a depositional environment dominated by aeolian transport. Fragments of Andean volcanic rocks (glass shards) in the wedge-fill suggest long-distance transport via a westerly component of wind direction. The wedges are interpreted as products of deep seasonal frost action in frozen ground, which produced open cracks that filled rapidly with partially non-local aeolian sediments. Many wedges cross cut carbonate crusts that formed under permafrost conditions in coastal Patagonia. The radiocarbon dating of carbonate crusts yielded an age of 25–27 kyr bp, while wedge-fill sediments are OSL dated to 14 670 ± 750 yr bp. This indicates that ground wedge formation occurred during a cold event (the Antarctic Cold Reversal period) that interrupted the permafrost degradation following the Last Glacial Maximum.
67 1 - 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 - PublicationRestrictedAn Oldest Dryas glacier expansion on Mount Pelister (Former Yugoslavian Republic of Macedonia) according to10Be cosmogenic dating(2018)
; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ;We provide a geomorphological analysis of a glacial valley on Mount Pelister, in Macedonia. Three boulders from a frontal moraine were dated with the cosmogenic nuclide isotope 10Be. The results demonstrate that the boulders have been exposed since 15.24 ± 0.85 ka. This age constrains the formation of the frontal moraine to the Oldest Dryas cold event. This age fits with that of other glacier deposits dated to the Older Dryas in the Alps, Balkans, Carpathians and Turkish mountains. The Pelister palaeoglacier has been reconstructed and its equilibrium line altitude extracted, returning a value of 2250 ma.s.l. This is in good agreement with the equilibrium line altitudes of most other reconstructed glaciers of the same age in the circum- Mediterranean mountains, demonstrating a comparable response to the Oldest Dryas event. Other palaeoenvironmental records near the Pelister mountain indicate that the Older Dryas was here characterized by a cold and remarkably dry event. The temporal relationship between Older Dryas glacier advances in the Balkan region and recorded changes in the Atlantic thermohaline circulation during the Laurentide Ice Sheet massive ice discharge (H1 event) confirms the strong climatic link between the pan-Mediterranean regions and the North Atlantic Ocean.118 6 - 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 - PublicationRestrictedEvidence for a Younger Dryas deglaciation in the Galicica Mountains (FYROM) from cosmogenic 36 ClThis study presents the first cosmogenic 36Cl surface exposure data from a moraine in the Former Yugoslav Republic of Macedonia (FYROM). Five limestone boulders from an end moraine in the Galicica Mountains (40.94°N, 20.83°E, 2050 m a.s.l.) were used for cosmogenic 36Cl surface exposure dating. The 36Cl concentrations from the five boulders are identical within their measurement uncertainties ruling out major effects of inheritance, erosion, or snow cover. The calculated ages are very consistent ranging from 11.3 ± 1.3 to 12.8 ± 1.4 ka (mean 12 ± 0.6 ka) after applying a Ca-spallation production rate of 56 at g−1 a−1 (LSD scaling) and correction for 5 mm ka−1 carbonate weathering and 2% snow shielding. The applied corrections for weathering and snow shielding cause a shift to older ages in the order of magnitude of ca. 5% on average, making the production rate the main impact on exposure ages. The ages point to a moraine formation during the Younger Dryas period, consistent with the timing of the last deglaciation in the Galicica Mountains derived from previous geomorphological studies in the area. The formation of a glacier was likely favoured by several topoclimatic factors, accounting for additional snow input. This interpretation is in line with regional studies on glaciation chronologies from Šara Range (FYROM/Republic of Kosovo), Retezat Mountains (Romania), Mt. Chelmos (Greece), Mount Orjen (Montenegro) and Durmitor (Montenegro). Lake sediment analyses of Prespa (Republic of Albania/FYROM/Greece), Maliq (Republic of Albania) and Dojran lakes (FYROM/Greece) indicate that cold conditions promoted the formation of a local cirque glacier. However, studies of sediment records of the adjacent lakes Ohrid (Republic of Albania/FYROM) and Prespa do not indicate the presence of a proximal glaciation. An explanation might be a combination of the small size of the cirque glacier, generating only small amounts of debris, and the karstic bedrock, which hampers fluvial transport and acts by its aquifer system as a natural sediment trap, as the fluvial transport of the sediments to the lakes is absorbed by the karst system.
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