Palaeo-environmental reconstruction of the Mercure Basin (Basilicata region) during MIS 13, through a multi-proxy analysis of lacustrine sediments

The main purpose of this work is to make a first evaluation of the potential of the carbonate lacustrine sediment of the Mercure Basin (Basilicata region), to preserve palaeoclimatic information during the Middle Pleistocene. For this purpose a multi-proxy analysis of the lacustrine sediments from a selected section of the basin was undertaken. The selected section contains several tephra layers, which constrains the timing of deposition to MIS 13. Stable isotopes (oxygen and carbon) and element content were tentatively interpreted as linked to climatic changes giving interesting results for this poorly studied interval

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 late MIS 5 Mediterranean tephra markers: A reappraisal from peninsular Italy terrestrial records

We present new tephrostratigraphic records from the late MIS 5 (ca 110e80 ka) terrestrial sediments from southern and central Italy. On the one hand, the central Italy record consists of an outcropping lacustrine sequence from the Sulmona intermountain basin that contains four trachyticephonolitic tephra layers (POP3, POP2a, POP2b, POP1), all of which show a K-alkaline affinity that is typical for the Roman co-magmatic Province. The POP3 and POP1 layers were dated by 40Ar/39Ar method at 106.2 1.3 ka (2s) and 92.4 4.6 ka (2s), respectively. The sequence in southern Italy, on the other hand, is represented by post-Tyrrhenian coastal deposits of the Cilento area, Campania, which contain two trachytic layers (CIL2, CIL1) that show the same K-alkaline affinity. Based on their chemical compositions and radiometric ages, POP3 and POP1 are firmly correlated with the marine tephra layers X-5 (105 2 ka) and C-22 (ca 90 ka), which, in turn, match tephras TM-25 and TM-23-11, respectively, in the lacustrine sequence of Lago Grande di Monticchio (southern Italy). Of note, the POP1 layer also matches the Adriatic Sea tephra PRAD 2517 that was previously correlated with the older X-5 layer. The tephra couplet POP2a and POP2b (ca 103 and 103.5 ka, extrapolated ages) are compatible with the TM- 24b and TM-24-3 tephras in Monticchio, which match both the stratigraphic positions and the chemical compositions. In the Cilento area, as well as the already described X-6 layer (ca 108 ka) (CIL2), we recognise a new stratigraphic superimposed layer (CIL1) that matches the POP3/TM-25/C-27/X-5 Mediterranean marker(s). In summary, the data presented here provide new chemical and 40Ar/39Ar chronological constraints towards a robust late MIS 5 tephrostratigraphy of the central Mediterranean, although at the same time, they also reveal how the tephrostratigraphy itself might be flawed when dealing with tephra markers that are not adequately constrained and characterised.Published31-451V. Storia eruttivaJCR Journa

Aligning and synchronization of MIS5 proxy records from Lake Ohrid (FYROM) with independently dated Mediterranean archives: implications for DEEP 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 the marine isotope stages (MIS) 15-1. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed palaeoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. Here, 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 presented here shows consistent differences with that initially proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this new 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 a detailed study of independent chronological tie points is important to align different records and to highlight asynchronisms of climate events. Moreover, Francke et al. (2016) have incorporated the new chronology proposed for tephra OH-DP-0499 in the final DEEP age model. This has reduced substantially the chronological discrepancies between the DEEP site age model and the model proposed here for the last glacial-interglacial transition

Sedimentological processes and environmental variability at Lake Ohrid (Macedonia, Albania) between 637 ka and the present

Lake Ohrid (Macedonia, Albania) is thought to be more than 1.2 million years old and host more than 300 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 composite depth 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 11 tephra layers (first-order tie points) and on tuning of bio-geochemical proxy data to orbital parameters (second-order tie points), the analyzed sediment sequence covers the last 637 kyr. The DEEP site sediment succession consists of hemipelagic sediments, which are interspersed by several tephra layers and infrequent, thin (< 5 cm) mass wasting deposits. The hemipelagic sediments can be classified into three different lithotypes. Lithotype 1 and 2 deposits comprise calcareous and slightly calcareous silty clay and are predominantly attributed to interglacial periods with high primary productivity in the lake during summer and reduced mixing during winter. The data suggest that high ion and nutrient concentrations in the lake water promoted calcite precipitation and diatom growth in the epilimnion during MIS15, 13, and 5. Following a strong primary productivity, highest interglacial temperatures can be reported for marine isotope stages (MIS) 11 and 5, whereas MIS15, 13, 9, and 7 were comparably cooler. Lithotype 3 deposits consist of clastic, silty clayey material and predominantly represent glacial periods with low primary productivity during summer and longer and intensified mixing during winter. The data imply that the most severe glacial conditions at Lake Ohrid persisted during MIS16, 12, 10, and 6, whereas somewhat warmer temperatures can be inferred for MIS14, 8, 4, and 2. Interglacial-like conditions occurred during parts of MIS14 and 8

Effects of organic removal techniques prior to carbonate stable isotope analysis of lacustrine marls: a case study from palaeo‐lake Fucino (central Italy)

Rationale The suitability of organic matter (OM) removal pre‐treatments in isotopic studies of lacustrine carbonates is currently under debate. Naturally occurring OM seems to have a negligible effect on the bulk isotopic composition of carbonates compared with changes induced by pre‐treatments. This study provides further insights into the possible effects induced by commonly used pre‐treatments on natural lacustrine carbonates. Methods Sixteen samples from the Fucino F1–F3 lacustrine succession (Abruzzo, central Italy) were characterised for their mineralogical and geochemical composition and each was split into three identical aliquots. One aliquot was left untreated while the remaining two were treated with NaOCl and H2O2 dilutions. The same treatment was applied to an internal standard consisting of pure Carrara marble. The treated and untreated samples were analysed for their carbon (δ13C values) and oxygen (δ18O values) isotope compositions using an Analytical Precision AP2003 isotope ratio mass spectrometer. Results The samples had variable proportions of endogenic and detrital components, the detrital portion being more (less) abundant during colder (warmer) climate phases. We observed that neither the NaOCl nor the H2O2 treatment was able to completely remove OM and therefore there was selective removal of compounds within the OM pool. A possible effect of pre‐treatment is the loss of carbonates intimately interspersed within the OM, as suggested by the evolution of isotopic ratios towards the local detrital array. Conclusions Our study highlights sample‐specific changes in geochemistry associated with sample pre‐treatments; however, such changes do not seem to lead to either systematic and/or predictable isotopic shifts. We suggest that the suitability of NaOCl or H2O2 pre‐treatments for OM removal should be evaluated on a case‐by‐case basis. In the specific case of lacustrine marls from palaeo‐lake Fucino containing relatively low amounts of OM and in which both detrital and endogenic carbonates occur, both pre‐treatments should be avoided

Sedimentological processes and environmental variability at Lake Ohrid (Macedonia, Albania) between 637 ka and the present

Lake Ohrid (Macedonia, Albania) is thought to be more than 1.2 million years old and host more than 300 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 composite depth 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 11 tephra layers (first-order tie points) and on tuning of bio-geochemical proxy data to orbital parameters (second-order tie points), the analyzed sediment sequence covers the last 637 kyr. The DEEP site sediment succession consists of hemipelagic sediments, which are interspersed by several tephra layers and infrequent, thin (< 5 cm) mass wasting deposits. The hemipelagic sediments can be classified into three different lithotypes. Lithotype 1 and 2 deposits comprise calcareous and slightly calcareous silty clay and are predominantly attributed to interglacial periods with high primary productivity in the lake during summer and reduced mixing during winter. The data suggest that high ion and nutrient concentrations in the lake water promoted calcite precipitation and diatom growth in the epilimnion during MIS15, 13, and 5. Following a strong primary productivity, highest interglacial temperatures can be reported for marine isotope stages (MIS) 11 and 5, whereas MIS15, 13, 9, and 7 were comparably cooler. Lithotype 3 deposits consist of clastic, silty clayey material and predominantly represent glacial periods with low primary productivity during summer and longer and intensified mixing during winter. The data imply that the most severe glacial conditions at Lake Ohrid persisted during MIS16, 12, 10, and 6, whereas somewhat warmer temperatures can be inferred for MIS14, 8, 4, and 2. Interglacial-like conditions occurred during parts of MIS14 and 8. © Author(s) 2016

An overview of Alpine and Mediterranean palaeogeography, terrestrial ecosystems and climate history during MIS 3 with focus on the Middle to Upper Palaeolithic transition

This paper summarizes the current state of knowledge about the millennial scale climate variability characterizing Marine Isotope Stage 3 (MIS 3) in S-Europe and the Mediterranean area and its effects on terrestrial ecosystems. The sequence of Dansgaard-Oeschger events, as recorded by Greenland ice cores and recognizable in isotope profiles from speleothems and high-resolution palaeoecological records, led to dramatic variations in glacier extent and sea level configuration with major impacts on the physiography and vegetation patterns, both latitudinally and altitudinally. The recurrent succession of (open) woodlands, including temperate taxa, and grasslands with xerophytic elements, have been tentatively correlated to GIs in Greenland ice cores. Concerning colder phases, the Greenland Stadials (GSs) related to Heinrich events (HEs) appear to have a more pronounced effect than other GSs on woodland withdrawal and xerophytes expansion. Notably, GS 9-HE4 phase corresponds to the most severe reduction of tree cover in a number of Mediterranean records. On a long-term scale, a reduction/opening of forests throughout MIS 3 started from Greenland Interstadials (GIs) 14/13 (ca. 55\u201348 ka), which show a maximum in woodland density. At that time, natural environments were favourable for Anatomically Modern Humans (AMHs) to migrate from Africa into Europe as documented by industries associated with modern hominin remains in the Levant. Afterwards, a variety of early Upper Palaeolithic cultures emerged (e.g., Uluzzian and Proto-Aurignacian). In this chronostratigraphic framework, attention is paid to the Campanian Ignimbrite tephra marker, as a pivotal tool for deciphering and correlating several temporal-spatial issues crucial for understanding the interaction between AMHs and Neandertals at the time of the Middle to Upper Palaeolithic transition

La dinamica del clima nell’ultimo ciclo glaciale-interglaciale

Attraverso questo primo incontro, il Gruppo di Lavoro Dinamica del paleoclima del CNR intende creare ed intensificare la rete tra i ricercatori italiani che si occupano di paleoclima, favorire la collaborazione tra la comunità paleoclimatica e di modellistica climatica ed individuare grandi sfide e temi di ricerca comuni per promuovere la partecipazione congiunta a programmi di ricerca nazionali ed internazionali