Sulmona Basin Research Articles

Evidence for a Constant Slip Rate Over the Last ∼40 ka Along the Mt. Morrone Fault System in Central Apennines

AbstractLocated in the easternmost portion of the Central Apennines, the Mt. Morrone normal fault system is one of the highest seismic hazards in Italy. Previous geological and geomorphological observations revealed the presence of a ∼22 km‐long NW‐SE right‐lateral en echelon fault system made of two parallel faults affecting Quaternary deposits. Our analysis focused on the westernmost fault, which bounds the Sulmona Basin. Cumulative offsets were identified and quantified using high‐resolution Digital Elevation Models derived from LiDAR, Satellite Pleiades images, and drone acquisition at the three sites. Morphological markers displaced from a few to tens of meters were dated using 36Cl exposure dating. The results would be suggesting a fault slip rate of 0.2–0.4 mm/a. The deformed markers that dated at 36–44 ka consist of alluvial terraces emplaced by the main streams flowing down from Mt. Morrone to the Sulmona Basin, subsequently incised, and preserved when the fluvial base level dropped because of the former Sulmona lake fluctuations. The yielded ages for these markers fit well with the last major aggradational event associated with the 35–40 ka Heinrich event described and dated to other fluvial basins in the Apennines. Furthermore, the estimated rate agrees with the values obtained in previous studies over shorter and longer periods (105−6 years) and within similar uncertainties. This might then suggest that the period recovered by this study encompasses the entire seismic cycle.

The Antarctic Ice Core Chronology 2023 (AICC2023) chronological framework and associated timescale for the European Project for Ice Coring in Antarctica (EPICA) Dome C ice core

Abstract. The EPICA (European Project for Ice Coring in Antarctica) Dome C (EDC) ice core drilling in East Antarctica reaches a depth of 3260 m. The reference EDC chronology, the AICC2012 (Antarctic Ice Core Chronology 2012), provides an age vs. depth relationship covering the last 800 kyr (thousands of years), with an absolute uncertainty rising up to 8000 years at the bottom of the ice core. The origins of this relatively large uncertainty are twofold: (1) the δ18Oatm, δO2/N2 and total air content (TAC) records are poorly resolved and show large gaps over the last 800 kyr, and (2) large uncertainties are associated with their orbital targets. Here, we present new highly resolved δ18Oatm, δO2/N2 and δ15N measurements for the EDC ice core covering the last five glacial–interglacial transitions; a new low-resolution TAC record over the period 440–800 ka BP (ka: 1000 years before 1950); and novel absolute 81Kr ages. We have compiled chronological and glaciological information including novel orbital age markers from new data on the EDC ice core as well as accurate firn modeling estimates in a Bayesian dating tool to construct the new AICC2023 chronology. For the first time, three orbital tools are used simultaneously. Hence, it is possible to observe that they are consistent with each other and with the other age markers over most of the last 800 kyr (70 %). This, in turn, gives us confidence in the new AICC2023 chronology. The average uncertainty in the ice chronology is reduced from 1700 to 900 years in AICC2023 over the last 800 kyr (1σ). The new timescale diverges from AICC2012 and suggests age shifts reaching 3800 years towards older ages over marine isotope stages (MISs) 5, 11 and 19. But the coherency between the new AICC2023 timescale and independent chronologies of other archives (Italian Lacustrine succession from Sulmona Basin, Dome Fuji ice core and northern Alpine speleothems) is improved by 1000 to 2000 years over these time intervals.

Liquefaction assessment of gravelly soils: the role of in situ and laboratory geotechnical tests through the case study of the Sulmona basin (Central Italy)

Even though liquefaction in gravelly soil is well documented in many earthquakes since 1891, most of the “simplified procedures” and national buildings codes still consider only sandy soil liquefaction in seismic hazard assessment. In this study, 109 sites of gravel liquefaction related to 27 historical earthquakes from 1891 to 2020 are reported, with a wide range of moment magnitudes, Mw , (5.3 to 9.2) and focal depths (5.4 to 33 km), highlighting the potential for liquefaction of gravelly soils even during moderate earthquakes. Although gravels are often thought to have hydraulic conductivities high enough to preclude liquefaction, gravels that have liquefied are generally well-graded sandy gravels. The sand content is typically 30% or more so that the hydraulic conductivity is governed by the sand size making them clearly liquefiable. Even for gravels with lower sand contents, a low permeability surface layer has often been observed that could restrict drainage and produce excess pore pressure during strong shaking.The epicentral distance calculated for gravel liquefaction sites plotted vs the magnitude of the earthquake event shows a pattern which closely follows similar curves provided in the literature for sandy soils. However, field observations of liquefaction in gravelly soils are less frequent in the historical record.In addition to examining gravel liquefaction sites in general, this paper provides a case history illustrating the difficulties of liquefaction assessment in gravels at a site in Santa Rufina (Sulmona basin, Central Italy). This site, characterised by high vertical and lateral stratigraphic variability, was selected for gravel liquefaction assessment using a combination of in-situ tests, laboratory geotechnical analysis, and geological studies. We found that, even if SPT- and DPT- based in-situ methods provide conflicting results, the availability of a borehole log, along with standard laboratory test results, proved to be fundamental to achieving a reliable assessment of the liquefaction hazard.

Millennial-scale oscillations in the Kuroshio\u2013Oyashio boundary during MIS 19 based on the radiolarian record from the Chiba composite section, central Japan

Marine isotope stage (MIS) 19 is considered to be the best orbital analog for the present interglacial. Consequently, clarifying the climatic features of this period can provide us with insights regarding a natural baseline for assessing future climate changes. A high-resolution radiolarian record from 800 to 750 ka (MIS 20 to MIS 18) was examined from the Chiba composite section (CbCS) of the Kokumoto Formation, including the Global Boundary Stratotype Section and Point for the lower–middle Pleistocene boundary on the Boso Peninsula on the Pacific side of central Japan. Millennial-scale oscillations in the Kuroshio warm and Oyashio cold currents were revealed by the Tr index, which is estimated using a simple equation based on radiolarian assemblages. The estimated Tr values ranged between 0.1 and 0.8 for MIS 18 through MIS 19, with minimum and maximum values corresponding to values observed off present day Aomori (41°N) and the Boso Peninsula (35°N), respectively. The observed patterns tended to be synchronous with the total radiolarian abundance associated with their production. Multiple maxima in radiolarian abundance occurred during periods of the Oyashio expanded mode before 785 ka and during periods of Kuroshio extension after 785 ka in MIS 19. Such increases in radiolarian abundance with the Kuroshio extension during MIS 19 are likely related to improvements in nutrient and photic environments with the development of a two-layer structure along the Kuroshio–Oyashio boundary zone. A similar pattern of millennial-scale climatic changes was also recognized in a precipitation record from the Sulmona Basin in central Italy, suggesting a close relationship with the CbCS record as a result of a large-scale climate system similar to the Arctic Oscillation in the northern hemisphere.

Fast Directional Changes during Geomagnetic Transitions: Global Reversals or Local Fluctuations?

Paleomagnetic investigations from sediments in Central and Southern Italy found directional changes of the order of 10∘ per year during the last geomagnetic field reversal (which took place about 780,000 years ago). These values are orders of magnitudes larger than what is expected from the estimated millennial timescales for geomagnetic field reversals. It is yet unclear whether these extreme changes define the timescale of global dipolar change or whether they indicate a rapid, but spatially localised feature that is not indicative of global variations. Here, we address this issue by calculating the minimum amount of kinetic energy that flows at the top of the core required to instantaneously reproduce these two scenarios. We found that optimised flow structures compatible with the global-scale interpretation of directional change require about one order of magnitude more energy than those that reproduce local change. In particular, we found that the most recently reported directional variations from the Sulmona Basin, in Central Italy, can be reproduced by a core-surface flow with rms values comparable to, or significantly lower than, present-day estimates of about 8 to 22 km/y. Conversely, interpreting the observations as global changes requires rms flow values in excess of 77 km/y, with pointwise maximal velocities of 127 km/y, which we deem improbable. We therefore concluded that the extreme variations reported for the Sulmona Basin were likely caused by a local, transient feature during a longer transition.

Tephrochronology of the central Mediterranean MIS 11c interglacial (∼425–395 ka): New constraints from the Vico volcano and Tiber delta, central Italy

Through a systematic integrated approach, which combined lithostratigraphic, geochronological and geochemical analyses of tephra from near-source sections of the peri-Tyrrhenian volcanoes and mid to distal settings, here we provide an improved tephrochronological framework for the Marine Isotope Stage 11c interglacial (MIS 11c, ∼425–395 ka) in the Central Mediterranean area. Specifically, we present the complete geochemical dataset and new high-precision 40Ar/39Ar ages of the previously poorly characterized earliest pyroclastic products of the Vico volcano (420–400 ka), including the Plinian eruptions of Vico α and Vico β and the immediately post-dating lower magnitude explosive events. Furthermore, we also provide new geochronological and geochemical data for the distal tephra layers preserved in the aggradational succession of the Tiber delta (San Paolo Formation), Roman area, which records sea level rise relating to the MIS 12 (glacial) to MIS 11 (interglacial) transition. Five pyroclastic units were recognized in Vico volcanic area, four out of which, Vico α, Vico β, Vico βtop (a minor eruption immediately following Vico β and temporally very close to it) and Vico δ were directly dated at 414.8 ± 2.2 ka, 406.5 ± 2.4 ka, 406.4 ± 2.0 ka and 399.7 ± 3.2 ka respectively (2σ analytical uncertainties). These new data allow a critical reappraisal of the previously claimed identifications of Vico tephra from mid-distal to ultra-distal successions (i.e., Vico-Sabatini volcanic districts, Roman San Paolo Formation and Castel di Guido archaeological site, Sulmona Basin, Valdarno and Lake Ohrid), which were unavoidably biased by the poor and incomplete geochemical and geochronological reference datasets previously available. Such an improvement of the tephrochronological framework brings great benefits to any future investigations (e.g., paleoclimatology, archaeology, active tectonic, volcanology) in the dispersal areas of the studied eruptions at the key point in time that is MIS 11.

The “Fan of the Terre Peligne”: Integrated Enhancement and Valorization of the Archeological and Geological Heritage of an Inner-Mountain Area (Abruzzo, Central Apennines, Italy)

The outstanding cultural heritage of Italy is intimately related to the landscape and its long-lasting history. Besides major cities, famous localities, and park areas, several minor places and areas hide important features that allow the enhancing of inner-mountain and hilly areas as well as local natural reserves. This enhancement is supported by combining different types of cultural tourism, such as the archeological and geological ones. In this paper, an integrated geological–archeological itinerary is presented, which aims to valorize both these aspects in the inner-mountain areas of the central Apennines. The itinerary, called the “Fan of the Terre Peligne”, is focused on the Terre Peligne area located in the Sulmona basin, in the central-eastern part of the Apennines chain (Abruzzo region, central Italy). It is composed of five sectors (one for each of the municipalities included) and incorporates traditional physical tools and digital ones. Here, the evidence of the Apennines formation is preserved from the origin of marine carbonate rocks to their deformation and the landscape shaping. The Terre Peligne intermontane basin became—and still is—one of the main transit areas for crossing the Italian peninsula since before Roman times and here many stages of Italian history are preserved. This allows outlining of the presence of man since prehistoric times, and here the name “Italia” was defined for the first time, in Corfinio, and to testify the connection between human and landscape history. A SWOT (strengths–weaknesses–opportunities–threats) analysis highlighted the main strengths, weaknesses, opportunities, and threats. Combining geological and archeological elements, which are intimately connected in this area, this itinerary intends to be an instrument for the enhancement and awareness of the natural and cultural heritage of a poorly known area that features outstanding geological, landscape, and human elements of the history of the inner Apennines.

Frequency and dynamics of millennial-scale variability during Marine Isotope Stage 19: Insights from the Sulmona Basin (central Italy)

Among past interglacial periods, Marine Isotope Stage (MIS) 19 is particularly interesting because its orbital geometry is very similar to that of the present interglacial. Here we present a high-resolution (sub-centennial) multiproxy record covering the ca. 790-770 ka interval, i.e. the interglacial MIS 19c and the ensuing glacial inception of MIS 19b, from a lacustrine sediment sequence retrieved from the Sulmona Basin (central Italy). The record has an independent chronology based on radiometric dating of six volcanic ash layers, and the resulting age model has a mean associated uncertainty of ±2.6 kyr. Variations in sediment geochemistry and mineralogy are interpreted in terms of past hydrological and temperature changes. Several millennial and sub-millennial events of reduced precipitation are well expressed. Comparisons with continental and marine records from the mid-latitude and sub-polar North Atlantic suggest a broad spatial expression for the observed events. Events occurring within the interglacial are not clearly associated with changes in marine proxies in the Iberian Margin, although similarities with the record from the sub-polar North Atlantic can be recognized and tentatively linked to changes in local hydrography having a downstream effect amplified by changes in atmospheric circulation. During the glacial inception, changes in the Sulmona record are coherent with changes in North Atlantic records, with drier events likely associated with meltwater-induced intervals of AMOC weakening. An event at ca. 785.6 ka may also reflect oceanic changes caused by freshwater discharges from residual ice-sheets and an outburst flood, similar to the 8.2 ka event in the Holocene.

Morphotectonics of the Tasso Stream - Sagittario River valley (Central Apennines, Italy)

ABSTRACT This work presents the morphotectonic map of the Tasso Stream-Sagittario River valley, located in the Central Abruzzo area (Marsica region), in one of the areas of highest average elevation in the Apennines chain between two main intermontane basins (i.e. the Sulmona basin and Fucino basin). It is bounded by one of the main drainage divides of Central Italy, separating the Adriatic side of the Apennines from the large endorheic Fucino area. The morphotectonic map of the Sagittario River valley is the result of an geomorphological analysis of the drainage at the basin scale in Central Italy and incorporates three main sections: orography and hydrography (upper right on the map), the main morphotectonic map (center and left on the map), and the morphotectonic profile section (lower on the map). This map provides a basis for the recognition of morphotectonic features at the basin scale, the detection of tectonic vs. surface processes’ control on the landscape, and the reconstruction of the landscape evolution of the Sagittario gorges, one of the main gorges incising the carbonate ridges of the Apennines. It contributes to defining the main phases of the Quaternary landscape evolution of the inner mountain landscape of the Apennines, resulting from the combination of alternating morphotectonics (i.e. rock uplift and local tectonics) and surface processes (i.e. slope, karst, glacial and fluvial processes).

On the reliability of the Matuyama–Brunhes record in the Sulmona Basin—Comment to ‘A reappraisal of the proposed rapid Matuyama–Brunhes geomagnetic reversal in the Sulmona Basin, Italy’ by Evans and Muxworthy (2018)

On the reliability of the Matuyama–Brunhes record in the Sulmona Basin—Comment to ‘A reappraisal of the proposed rapid Matuyama–Brunhes geomagnetic reversal in the Sulmona Basin, Italy’ by Evans and Muxworthy (2018)

The marine isotope stage 1–5 cryptotephra record of Tenaghi Philippon, Greece: Towards a detailed tephrostratigraphic framework for the Eastern Mediterranean region

The iconic climate archive of Tenaghi Philippon (TP), NE Greece, allows the study of short-term palaeoclimatic and environmental change throughout the past 1.3 Ma. To provide high-quality age control for detailed palaeoclimate reconstructions based on the TP archive, (crypto)tephra studies of a peat core ‘TP-2005’ have been carried out for the 0–130 ka interval. The results show that the TP basin is ideally positioned to receive tephra fall from both the Italian and Aegean Arc volcanic provinces. Two visible tephra layers, the Santorini Cape Riva/Y-2 (c. 22 ka) and the Campanian Ignimbrite (CI)/Y-5 (c. 39.8 ka) tephras, and six primary cryptotephra layers, namely the early Holocene E1 tephra from the Aeolian Islands (c. 8.3 ka), the Campanian Y-3 (c. 29 ka) and X-6 tephras (c. 109.5 ka), as well as counterpart tephras TM-18-1d (c. 40.4 ka), TM-23-11 (c. 92.4 ka) and TM-33-1a (c. 116.7 ka) from the Lago Grande di Monticchio sequence (southern Italy), were identified along with repeatedly redeposited Y-2 and CI tephra material. Bayesian modelling of the ages of seven of the primary tephra layers, 60 radiocarbon measurements and 20 palynological control points have been applied to markedly improve the chronology of the TP archive. This revised chronology constrains the age of tephra TM-18-1d to 40.90–41.66 cal ka BP (95.4% range). Several tephra layers identified in the TP record form important isochrons for correlating this archive with other terrestrial (e.g., Lago Grande di Monticchio, Sulmona Basin and Lake Ohrid) and marine (e.g., Adriatic Sea core PRAD 1-2 and Aegean Sea core LC21) palaeoclimate records in the Mediterranean region.

A re-appraisal of the proposed rapid Matuyama–Brunhes geomagnetic reversal in the Sulmona Basin, Italy

A re-appraisal of the proposed rapid Matuyama–Brunhes geomagnetic reversal in the Sulmona Basin, Italy

New insights into the onset and evolution of the central Apennine extensional intermontane basins based on the tectonically active L’Aquila Basin (central Italy)

Study of the tectonically active L'Aquila Basin offers new insights into both the creation of the extensional intermontane basins of the central Apennines of Italy and their tectono-sedimentary evolution through time. The combination of large mammal remains, ostracods, molluscs, Mousterian tools, and 14 C dating allows better definition of the onset and stratigraphic evolution of the L'Aquila Basin. Interpretation of a seismic reflection profile and well-log data allow evaluation of the subsurface setting of this sedimentary basin and its tectono-sedimentary evolution. The occurrence of a wedge-shaped seismic unit at the base of the basin sedimentary succession defines the first phase of basin fill during a late Piacenzian–Gelasian synrift stage. Activity along the main fault of the extensional fault system responsible for the onset and subsequent development of the western sector of the L'Aquila Basin (L'Aquila– Scoppito subbasin) migrated from southwest to northeast, reaching the presently active Mount Pettino normal fault only in the late Pleistocene–Holocene. The onset of sedimentation in the L'Aquila Basin was synchronous with the onset in the Tiberino Basin, and so the idea that these extensional GSA Bulletin; Month/Month 2017; v. 129; no. intermontane basins become progressively younger from the Tyrrhenian toward the Adriatic side of the central Apennines is rejected. In the northern and central Apen-nines, only two major syndepositional ex-tensional domains can be recognized: a late Miocene rifting area, which includes all the late Miocene extensional basins in Tuscany, and a late Pliocene to earliest Pleistocene rifting area, which possibly includes all the intermontane basins from the Tiberino Basin to the Sulmona Basin. The different time gaps between compressional and exten-sional deformation at any given locality in the central Apennines could indicate a partial decoupling of processes responsible for the migration of shortening and extension toward the foreland. Diachroneity between the eastward migration of shortening in the foreland and extension in the inner part of the orogen supports the notion that the central Apennines were created as a result of a partially decoupled collision zone. Study of the onset of the central Apennine extensional intermontane basins, together with their seismic activity, indicates that the central Apennine postorogenic extensional domain represents an archive of ~3 m.y. of continued crustal extension. These findings help to refine models of the long-term extensional rate of the central Apennines, and they provide a basis for more reliable seismotectonic models for one of the most seismically active sectors of the central Mediterranean area.

Middle Pleistocene (MIS 14) environmental conditions in the central Mediterranean derived from terrestrial molluscs and carbonate stable isotopes from Sulmona Basin (Italy)

A paleosol from the Middle Pleistocene lacustrine-fluvial succession of Sulmona Basin, central Italy, was analysed for the land snail shell content, and the stable isotope composition of the shells and associated pedogenic carbonates. The paleosol – known as Fiorata Paleosol – is covered by a thick tephra layer dated to ca. 527ka allowing the pedogenetic horizons to be correlated to the marine isotope stage (MIS) 14-early MIS 13 interval. The terrestrial mollusc assemblage contained few individuals and was characterized by a low number of species which predominantly indicate open and dry habitats, thus suggesting that Fiorata Paleosol likely developed during glacial conditions of the MIS 14. The δ13C values of pedogenic carbonates and terrestrial shells indicate prevailing C3-type vegetation, probably marked by some degree of water stress. Calculation of the δ18O precipitation values, derived from pedogenic carbonates and shell δ18O values, indicate that the average temperature was 3–5°C lower than present day. This study highlights how paleosols, despite offering only snapshots of past climate and environments, provide valuable complementary information to paleoclimatic data obtained in the adjacent lacustrine intervals, specifically for the Sulmona successions.

Active faulting, 3-D geological architecture and Plio-Quaternary structural evolution of extensional basins in the central Apennine chain, Italy

Abstract. The general basin and range Apennine topographic characteristic is generally attributed to the presently active normal fault systems, whose long-term activity (throughout the Quaternary) is supposed to have been responsible for the creation of morphological/structural highs and lows. By coupling field geological survey and geophysical investigations, we reconstructed the 3-D geological model of an inner tectonic basin of the central Apennines, the Subequana Valley, bounded to the northeast by the southern segment of one of the major active and seismogenic normal faults of the Apennines, known as the Middle Aterno Valley–Subequana Valley fault system. Our analyses revealed that, since the late Pliocene, the basin evolved in a double half-graben configuration through a polyphase tectonic development. An early phase, Late Pliocene–Early Pleistocene in age, was controlled by the ENE–WSW-striking and SSE-dipping Avezzano–Bussi fault, that determined the formation of an early depocentre towards the N–NW. Subsequently, the main fault became the NW–SE-striking faults, which drove the formation during the Quaternary of a new fault-related depocentre towards the NE. By considering the available geological information, a similar structural evolution has likely involved three close tectonic basins aligned along the Avezzano–Bussi fault, namely the Fucino Basin, the Subequana Valley, and the Sulmona Basin, and it has been probably experienced by other tectonic basins of the chain. The present work therefore points out the role of pre-existing transverse tectonic structures, inherited by previous tectonic phases, in accommodating the ongoing tectonic deformation and, consequently, in influencing the structural characteristics of the major active normal faults. This has implications in terms of earthquake fault rupture propagation and segmentation. Lastly, the morpho-tectonic setting of the Apennine chain results from the superposition of deformation events whose geological legacy must be considered in a wider evolutionary perspective. Our results testify that a large-scale basin and range geomorphological feature – often adopted for morpho-tectonic and kinematic evaluations in active extensional contexts, as in the Apennines – just led by range-bounding active normal faults may be actually simplistic, as it could not be applied everywhere, owing to peculiar complexities of the local tectonic histories.

A Last Interglacial record of environmental changes from the Sulmona Basin (central Italy)

Here we present a multiproxy record (δ13C, δ18O, major and minor element composition, mineralogy, and low-resolution biogenic silica content) from a lacustrine succession in the Sulmona Basin, central Italy. Based on previous tephrochronological constraints and a new 40Ar/39Ar dating of a tephra matching the widespread X-6 tephra, the record spans the ca. 129–92ka period and documents at sub-orbital scale the climatic and environmental changes over the Last Interglacial and its transition to the Last Glacial period. The δ18O composition is interpreted as a proxy for the amount and seasonality of local precipitation, whereas variations in elemental and mineralogical composition are inferred to reflect climatic-driven changes in clastic sediment input. The observed variations are consistent among the different proxies, and indicate that periods of reduced precipitation were marked by enhanced catchment erosion, probably due to a reduction in vegetation cover. The first part of the Last Interglacial shows the most negative δ18O values. Comparison with pollen records from the Mediterranean suggests a greater seasonality of the precipitation at this time. At millennial-to-centennial time scales, comparison of the Sulmona record with speleothem δ18O records from central Italy highlights a highly coherent pattern of hydrological evolution, with enhanced variability and similar events of reduced precipitation consistently recorded by each isotope record. The observed intra-interglacial variability can potentially be linked, within the uncertainties associated with each age model, to similar variations observed in sea-surface temperature records from the Mediterranean and the North Atlantic, suggesting a link between Mediterranean hydrology and North Atlantic temperature and circulation patterns that persists during periods of low ice volume.

WITHDRAWN: A Last Interglacial record of environmental changes from the Sulmona Basin (central Italy)

WITHDRAWN: A Last Interglacial record of environmental changes from the Sulmona Basin (central Italy)

First tephrostratigraphic results of the DEEP site record from Lake Ohrid (Macedonia and Albania)

Abstract. A tephrostratigraphic record covering the Marine Isotope Stages (MIS) 1–15 was established for the DEEP site record of Lake Ohrid (Macedonia and Albania). Major element analyses (energy dispersive spectroscopy (EDS) and wavelength-dispersive spectroscopy (WDS)) were carried out on juvenile fragments extracted from 12 tephra layers (OH-DP-0115 to OH-DP-2060). The geochemical analyses of the glass shards of all of these layers suggest an origin in the Italian volcanic provinces. They include the Y-3 (OH-DP-0115, 26.68–29.42 ka cal BP), the Campanian Ignimbrite–Y-5 (OH-DP-0169, 39.6 ± 0.1 ka), and the X-6 (OH-DP-0404, 109 ± 2 ka) from the Campanian volcanoes, the P-11 of Pantelleria (OH-DP-0499, 133.5 ± 2 ka), the Vico B (OH-DP-0617, 162 ± 6 ka) from the Vico volcano, the Pozzolane Rosse (OH-DP-1817, 457 ± 2 ka) and the Tufo di Bagni Albule (OH-DP-2060, 527 ± 2 ka) from the Colli Albani volcanic district, and the Fall A (OH-DP-2010, 496 ± 3 ka) from the Sabatini volcanic field. Furthermore, a comparison of the Ohrid record with tephrostratigraphic records of mid-distal archives related to the Mediterranean area allowed the recognition of the equivalents of other less known tephra layers, such as the TM24a–POP2 (OH-DP-0404, 102 ± 2 ka) recognized in the Lago Grande di Monticchio and the Sulmona Basin, the CF-V5–PRAD3225 (OH-DP-0624, ca. 163 ± 22 ka) identified in the Campo Felice Basin and the Adriatic Sea, the SC5 (OH-DP-1955, 493.1 ± 10.9 ka) recognized in the Mercure Basin, and the A11/12 (OH-DP-2017, 511 ± 6 ka) sampled at the Acerno Basin, whose specific volcanic sources are still poorly constrained. Additionally, one cryptotephra (OH-DP-0027) was identified by correlation of the potassium X-ray flourescence (XRF) intensities from the DEEP site with those from a short core of a previous study from Lake Ohrid. In these cores, a maximum in potassium is caused by glass shards, which were correlated with the Mercato tephra (8.43–8.63 ka cal BP) from Somma–Vesuvius. The tephrostratigraphic work presented here allows, for the first time, the extension of a consistent part of the Middle Pleistocene tephrostratigraphy of Italian volcanoes as far as the Balkans. The establishment of the tephrostratigraphic framework for the Lake Ohrid record provides important, independent tie points for the age–depth model of the DEEP site sequence, which is a prerequisite for palaeoclimatic and palaeoenvironmental reconstructions. Furthermore, this age–depth model will help to improve and re-evaluate the chronology of other, both undated and dated tephra layers from other records. Thus, the Lake Ohrid record may potentially become the template for the central Mediterranean tephrostratigraphy, especially for the hitherto poorly known and explored lower Middle Pleistocene period.

Tephra layers along the southern Tyrrhenian coast of Italy: Links to the X-5 & X-6 using volcanic glass geochemistry

We present the geochemistry of glass fragments from three visible tephra layers outcropping in Southern Italy. Two tephra deposits (LeS1 and LeS2), outcropping in the Palinuro area (Cilento, Southern Italy), correspond stratigraphically to the CIL1 and CIL2 tephra units (Giaccio et al., 2012), respectively; in turn these are correlated with the X-5 (ca. 105ka) and X-6 (ca. 108ka) marine tephra markers on the basis of their major element glass compositions. In order to reinforce these tephra correlations we examine both their major and trace element glass compositions. LeS1 compositions were compared with other correlatives of the X-5 tephra layer (POP3 [Sulmona basin], TM-25 [Lago Grande di Monticchio (LGdM)], CIL1 [Palinuro]) from the central Mediterranean. Our data validate a correlation of the Palinuro tephra layer, LeS1, to the X-5 correlatives. The Palinuro tephra deposit, LeS2, has glass compositions which correspond precisely with correlatives of the X-6 marker tephra (CIL2 [Palinuro], TM-27 [LGdM], I-9 [Ionian Sea] and PRAD 2812 [PRAD1-2, Adriatic Sea]). A tephra in the Valle del Crati (Calabria) appears to overlap in composition with the LeS2 tephra, indicating a probable correlation with the X-6 marker. These new data provide a detailed geochemical characterisation of two widespread marker horizons and are crucial for establishing precise correlations of sedimentary archives across the central Mediterranean region.

How fast was the Matuyama–Brunhes geomagnetic reversal? A new subcentennial record from the Sulmona Basin, central Italy

How fast was the Matuyama–Brunhes geomagnetic reversal? A new subcentennial record from the Sulmona Basin, central Italy