Aligning MIS5 proxy records from Lake Ohrid (FYROM) with independently dated Mediterranean archives: implications for core chronology

The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through marine isotope record. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed paleoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. In this paper, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70 ka and how the results can be correlated with directly/indirectly radiometrically-dated Mediterranean marine and continental proxy records. The alternative age model obtained shows consistent differences with that proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how important a detailed study of independent chronological tie points is for synchronizing different records and to highlight asynchronisms of climate events

Sedimentological processes and environmental variability at Lake Ohrid (Macedonia, Albania) between 640 ka and present day

Lake Ohrid (FYROM, Albania) is thought to be more than 1.2 million years old and hosts more than 200 endemic species. As a target of the International Continental Scientific Drilling Program (ICDP), a successful deep drilling campaign was carried out within the scope of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project in 2013. Here, we present lithological, sedimentological, and (bio-)geochemical data from the upper 247.8 m of the overall 569 m long DEEP site sediment succession from the central part of the lake. According to an age model, which is based on nine tephra layers (1st order tie points), and on tuning of biogeochemical proxy data to orbital parameters (2nd order tie points) and to the global benthic isotope stack LR04 (3rd order tie points), respectively, the analyzed sediment sequence covers the last 640 ka

Lake Ohrid’s tephrochronological dataset reveals 1.36 Ma of Mediterranean explosive volcanic activity

Tephrochronology relies on the availability of the stratigraphical, geochemical and geochronological datasets of volcanic deposits, three preconditions which are both often only fragmentary accessible. This study presents the tephrochronological dataset from the Lake Ohrid (Balkans) sediment succession continuously reaching back to 1.36 Ma. 57 tephra layers were investigated for their morphological appearance, geochemical fingerprint, and (chrono-)stratigraphic position. Glass fragments of tephra layers were analyzed for their major element composition using Energy-Dispersive-Spectroscopy and Wavelength-Dispersive Spectroscopy and for their trace element composition by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry. Radiometric dated equivalents of 16 tephra layers and orbital tuning of geochemical proxy data provided the basis for the age-depth model of the Lake Ohrid sediment succession. The age-depth model, in turn, provides ages for unknown or undated tephra layers. This dataset forms the basis for a regional stratigraphic framework and provides insights into the central Mediterranean explosive volcanic activity during the last 1.36 Ma

The recent evolution of the salt marsh ‘Pantano Grande’ (NE Sicily, Italy): interplay between natural and human activity over the last 3700 years

Combined natural processes and human activities shaped the late Holocene landscape history in many Mediterranean regions. This is especially true with areas subjected to specific human interest, such as coastal areas morphologically suitable to the establishment of harbours. Here, we test the hypothesis on the location of the Roman harbour Portus Trajectus in Peloro Cape (NE Sicily, Italy) and describe the evolution of the area over the last 3700 years through lithostratigraphic, geochemical, meiofauna and microfossil analyses performed on a new sediment core recovered from the coastal salt marsh Pantano Grande (aka Lago di Ganzirri). The age–depth model was developed on radiocarbon dates and geochemical fingerprinting of two tephra layers. Results indicate that the area underwent dramatic changes ca. 650 bce. The anthropogenic impact of Greek colonies may have contributed to modifying the coastal environment of Peloro Cape due to their widespread impact on natural resources. This happened at many localities in the Mediterranean, indicating the magnitude of impact of the Greek colonies over the landscape. According to our results, it is unlikely that the current Pantano Grande basin was used as a harbour in Roman times, although the presence of a harbour in the nearby Pantano Piccolo marsh cannot be excluded. Pantano Grande had been isolated from the sea for more than 2000 years. Human intervention in the 19th century halted that isolation and provided the background for the ecological, economic and social functions the salt marsh performs today

Central Mediterranean tephrochronology for the time interval 250–315 ka derived from the Fucino sediment succession

In the lacustrine succession F4-F5 of the Fucino Basin, central Italy, 20 visible tephra layerswere identified in the time interval 250–315 ka (Marine Isotope Stages 8–9). Fifteen of them contained suitablematerial to explore their volcanic sources. Among these tephra some well-known eruptions and eruptive sequences of the Roman and Roccamonfina volcanoes were identified, such as the Tufo Giallo di Sacrofano and the Lower White Trachytic Tuff, respectively. Furthermore, the sediment succession documents a more complex eruptive history of the Sabatini, Vulsini, Colli Albani andRoccamonfinavolcanic complexes during theinvestigated period, asinferred from previously undescribed tephra deposits. Single-crystal-fusion 40Ar/39Ar dating of two of the inspected tephra layers combined with two already published tephra ages provided the basis for a Bayesian age-depth model. The modelled tephra ages allow chronological constraining of so-far undefined eruptions of the Sabatini (272.54.7, 281.84.7, 308.52.8, 312.82.1 ka), the Vulsini (311.72.3, 311.92.3 ka) and the Colli Albani (301.03.6 ka) volcanic districts. Two tephra layers of an undefined volcanic source from the Roman volcanoes have modelled ages of 309.52.7 and 310.52.6 ka. The new 40Ar/39Ar and modelled ages were further used for a reassessment of the timing of already known and dated eruptive units, such as the Tufo Giallo di Sacrofano (40Ar/39Ar: 289.34.8 ka). Tephra tentatively correlated with the Valle Santa Maria, Case Pisello and the White Trachytic Tuff Unit E3 or Unit F offer modelled ages for these eruptions of 296.63.9, 301.83.5 and 303.63.4 ka, respectively. The results complete the tephrostratigraphical investigations of the c. 425 ka old F4-F5 record, extend the Mediterranean tephrostratigraphical framework and provide a significant contribution for improving knowledge on Italian volcanic explosive activit

The recent evolution of the salt marsh ‘Pantano Grande’ (NE Sicily, Italy): interplay between natural and human activity over the last 3700 years

Abstract Combined natural processes and human activities shaped the late Holocene landscape history in many Mediterranean regions. This is especially true with areas subjected to specific human interest, such as coastal areas morphologically suitable to the establishment of harbours. Here, we test the hypothesis on the location of the Roman harbour Portus Trajectus in Peloro Cape (NE Sicily, Italy) and describe the evolution of the area over the last 3700 years through lithostratigraphic, geochemical, meiofauna and microfossil analyses performed on a new sediment core recovered from the coastal salt marsh Pantano Grande (aka Lago di Ganzirri). The age?depth model was developed on radiocarbon dates and geochemical fingerprinting of two tephra layers. Results indicate that the area underwent dramatic changes ca. 650 bce. The anthropogenic impact of Greek colonies may have contributed to modifying the coastal environment of Peloro Cape due to their widespread impact on natural resources. This happened at many localities in the Mediterranean, indicating the magnitude of impact of the Greek colonies over the landscape. According to our results, it is unlikely that the current Pantano Grande basin was used as a harbour in Roman times, although the presence of a harbour in the nearby Pantano Piccolo marsh cannot be excluded. Pantano Grande had been isolated from the sea for more than 2000 years. Human intervention in the 19th century halted that isolation and provided the background for the ecological, economic and social functions the salt marsh performs today.Introduction Study site Materials and methods - Sediment sampling - Age–depth model - Tephra layer analysis - X‐ray fluorescence analysis - Meiofauna analysis - Dinocyst analysis Results - Geochemistry of tephra layers - Chronology - Late Holocene stratigraphy of Pantano Grande Discussion Conclusio

Central Mediterranean tephrochronology between 313 and 366 ka. New insights from the Fucino paleolake sediment succession

Thirty-two tephra layers were identified in the time-interval 313–366 ka (Marine Isotope Stages 9–10) of the Quaternary lacustrine succession of the Fucino Basin, central Italy. Twenty-seven of these tephra layers yielded suitable geochemical material to explore their volcanic origins. Investigations also included the acquisition of geochemical data of some relevant, chronologically compatible proximal units from Italian volcanoes. The record contains tephra from some well known eruptions and eruptive sequences of Roman and Roccamonfina volcanoes, such as the Magliano Romano Plinian Fall, the Orvieto–Bagnoregio Ignimbrite, the Lower White Trachytic Tuff and the Brown Leucitic Tuff. In addition, the record documents eruptions currently undescribed in proximal (i.e. near-vent) sections, suggesting a more complex history of the major eruptions of the Colli Albani, Sabatini, Vulsini and Roccamonfinavolcanoes between 313 and 366 ka. Six of the investigated tephra layers were directly dated by single-crystal-fusion 40Ar/39Ar dating, providing the basis for a Bayesian age–depth model and a reassessment of the chronologies for both already known and dated eruptive units and for so far undated eruptions. The results provide a significant contribution for improving knowledge on the peri-Tyrrhenian explosive activity as well as for extending the Mediterranean tephrostratigraphical framework, which was previously based on limited proximal and distal archives for that time interval

Mid-to-late Holocene upper slope contourite deposits off Capo Vaticano (Mediterranean Sea): High-resolution record of contourite cyclicity, bottom current variability and sandy facies

none13noThe upper continental slope offshore Capo Vaticano (southern Tyrrhenian Sea) is characterized by a contourite depositional system with well-developed elongated sediment drifts. This system is related to a northward paleo-bottom current, similar to the present-day modified-Levantine Intermediate Water (modified-LIW) flowing from the Messina Strait. In this work, we show results from an integrated analysis of descriptive oceanography, high-resolution seismic profiles and core data (i.e., grain size, foraminiferal assemblages, tephrostratigraphy and AMS radiocarbon dating) collected from the crest and moat sectors of drift deposits. The studied succession formed since the mid Holocene, under the action of the modified-LIW and the stratigraphic architecture indicates an upslope migration of the moat and rather stable position of the crest sector. Grain-size features recorded from two sediment cores indicate the occurrence of a succession of complete bi-gradational sand-rich contourite sequences. Sandy facies were observed both as lag deposits formed in active moat channel and as coarser intervals of bi-gradational sequences forming drift deposits close to its crest. Their occurrence would highlight that upper slope environments impacted by intermediate water masses and proximal to sandy sources may represent favorable settings for accumulation of sandy sediment. The moat sector is characterized by a more complex stratigraphic record, where either moat sedimentation or lateral deposition of finer sediment occur, suggesting that further investigation is required to better understand this complex element of contourite systems. Based on available age information, some of the bi-gradational sequences probably formed during the Dark Age Cold Period, providing example of a small-scale cyclicity of contourite deposition, likely related to short-term (possibly multicentennial scale) fluctuations of the paleo modified-LIW. According to age constraints and analysis of foraminiferal assemblages, these fluctuations were likely governed by climate variations, with a weaker activity during warmer periods and faster currents during colder events.openMartorelli E., Bosman A., Casalbore D., Chiocci F., Conte A.M., Di Bella L., Ercilla G., Falcini F., Falco P., Frezza V., Gaglianone G., Giaccio B., Mancini M.Martorelli, E.; Bosman, A.; Casalbore, D.; Chiocci, F.; Conte, A. M.; Di Bella, L.; Ercilla, G.; Falcini, F.; Falco, P.; Frezza, V.; Gaglianone, G.; Giaccio, B.; Mancini, M