Search results for " Holocene"

A new marker for sea surface temperature trend during the last centuries in temperate areas: Vermetid reef

2004

The presence of Vermetid reefs in temperate waters, their diffusion in the Mediterranean Sea, and the possibility of performing 14 C ages allowed the use of Vermetids as an indicator of sea level changes. We present new data on sea climate trend fluctuations that could be interpreted as Sea Surface Temperature (SST) variations, recorded on Vermetid (Dendropoma petraeum) reefs, by means of isotopic analysis. The isotopic records show positive values of the d 18 O relative to present-day values in the period between 1600 and 1850 AD; this deviation occurs in association with the climatic cooling event known as Little Ice Age (LIA). Subsequently, we can observe the warming trend that character…

Organic lacustrine sediment varves as indicators of past precipitation changes: a 3,000-year climate record from Central Finland

2015

Annually laminated (varved) sediments from Lake Kallio-Kourujärvi, Central Finland, provide high-resolution sedimentological data for the last three millennia. These varves consist of two laminae that represent (1) deposition during the spring-to-autumn growing season, composed of degraded organic matter and a variety of microfossils, and (2) deposition during winter, composed of fine-grained homogenous organic matter. Because of the absence of a clastic lamina, these varves differ from the typical, well-described, clastic-organic varve sequences in Fennoscandian lakes. Such organic varves in Finnish lakes have not been studied in detail before. Three thousand varves were counted and their …

Olea europaea L. in the North Mediterranean basin during the Pleniglacial and the Early–Middle Holocene

2010

17 páginas, 5 figuras, 2 tablas.

Human settlements in the Mediterranean and the sea level changes from 12 ka to the present

2012

Understanding past sea-level change plays an important role in determining the underlying causes, and also allows the extrapolation of past sea levels to locations and epochs for which there are no instrumental data. A compilation of global sea-level estimates based on deep-sea oxygen isotope ratios at millennial-scale resolution or higher was published since ‘70. These global sea level curves do not take in account isostasy and tectonics. Observed sea level change can be reconstructed from dated fossils, coral reef terraces, speleothems, emerged and forming terraces on coastal areas, archaeological and other markers well connected with sea level. Because of the lack of coral reefs in the M…

Paleoclimatic and Paleoceanographic reconstruction of the Pleistocene-Holocene through the study of planktonic foraminifera of two sedimentary cores …

2017

Abrupt Alnus population decline at the end of the first millennium CE in Europe - The event ecology, possible causes and implications

2019

The study, based on the examination of 70 published and unpublished pollen profiles from Poland and supplementary data from the surrounding regions, shows that an abrupt, episodic Alnus population decline at the end of the first millennium CE was a much more widespread event than has been previously reported, spanning large areas of the temperate and boreal zones in Europe. The data from Poland suggest that the decline was roughly synchronous and most likely occurred between the 9th and 10th centuries, with strong indications for the 10th century. The pollen data indicate that human impacts were not a major factor in the event. Instead, we hypothesize that one or a series of abrupt climatic…

Planktonic foraminifera as proxies of the Holocene climatic variability (Tyrrhenian, Mediterranean Sea)

2017

Introduction. The focus of this study is the paleoclimatic reconstruction of the southern Tyrrhenian between ~9.2 and 2.9 ka, through the study of planktonic foraminiferal assemblages and stable isotopes, and comparing data with other coeval intervals. Several authors have studied the climatic sensitivity of Holocene planktonic foraminifera in different parts of the Mediterranean. Planktonic foraminifera produce good records of Holocene climatic variability, especially as regards the suborbital events such as Bond events (Bond et al., 1997) and other cooling/warming oscillations. Therefore, the obtained eco-biostratigraphy has allowed us to analyze how climatic forcing influenced sea surfac…

1200-yr high-resolution terrestrial climate archive from the middle of the Mediterranean: The sedimentary record from Lake “Specchio di Venere” on Pa…

2011

The special location of Lake "Specchio di Venere" on Pantelleria Island in the Sicily Channel (Mediterranean Sea) between Tunisia and Sicily offers a unique terrestrial archive recording atmospheric changes, which are otherwise difficult to decipher in the marine records from this area. The lake is an endorheic saline basin with a maximum depth of 12.5 m. As the water input depends on rainfall, precipitation variations influence changes of the lake's water chemistry. In summer 2008, Lake Venere was cored with a modified Livingstone corer revealing a composite sedimentary sequence of 10.29 m length. Two radiocarbon dates form a preliminary age model indicating a very high sedimentation rate …

Spatio-temporal patterns of Holocene vegetation change in southern Sicily

2012

Few examples of natural forest remain near the Mediterranean coast. Therefore, it is difficult to study how coastal forests respond to climatic change or their resilience to human impact. We developed new sedimentary record of Holocene vegetation and fire history at Lago Preola, a coastal lake in southwestern Sicily (Italy). In order to verify the existence of forest at large scale on the coast, we compare pollen from Lago Preola, a medium-sized lake (33 ha), to Gorgo Basso, a small lake (3 ha) located nearby with the aim of separating local from extra-local vegetation dynamics through time using pollen percentages and influx. We then compare Lago Preola pollen to the record from Biviere di…

Past aquatic environments in the Levant inferred from stable isotope compositions of carbonate and phosphate in fish teeth

2019

Here we explore the carbon and oxygen isotope compositions of the co-existing carbonate and phosphate fractions of fish tooth enameloid as a tool to reconstruct past aquatic fish environments and harvesting grounds. The enameloid oxygen isotope compositions of the phosphate fraction (δ18OPO4) vary by as much as ~4‰ for migratory marine fish such as gilthead seabream (Sparus aurata), predominantly reflecting the different saline habitats it occupies during its life cycle. The offset in enameloid Δ18OCO3-PO4 values of modern marine Sparidae and freshwater Cyprinidae from the Southeast Mediterranean region vary between 8.1 and 11.0‰, similar to values reported for modern sharks. The mean δ13C …