We investigated the deep-sea sedimentary sequence of core MD012422 corresponding to the last 350 ka (since marine isotopic stage, MIS 10) from off Shikoku Island, NW Pacific Ocean, and refined its ...tephrostratigraphy. We detected many tephras and cryptotephras and correlated them with terrestrial tephras on the basis of the major- and trace-element compositions of their glass shards. Then we cross-checked our results against the reported marine tephrostratigraphy in the NW Pacific area and assessed the relative timing of tephra eruptions and bioevents. Many widespread tephras and cryptotephras originated from the Kyushu volcanic zone (Kuju, Aso, Kakuto, Aira, Ata, and Kikai volcanoes/calderas), along with the Takayama-Ng1 tephra (Tky-Ng1) from Suiendani volcano in central Honshu, were detected in the core. These tephras were used to validate and refine the reported NW Pacific marine tephrostratigraphy and to develop useful time-synchronous markers for this ocean area. Among the tephras, Ata-Torihama (Ata-Th) occurs at the MIS 7/8 transition (ca. 240 ka) and its horizon overlaps with a calcareous nannofossil biohorizon, the first appearance datum (FAD) of Emiliania huxleyi. Ata-Th and this biohorizon are stratigraphically above the Tky-Ng1 (MIS 8/9 transition, 290–300 ka) and Kakuto (Kkt, MIS 9/10 transition, 330–340 ka) tephras, and these tephras have the same stratigraphic relationship with this biohorizon in deep-sea sediments from the East China Sea, off Shikoku Island, and off central Honshu. However, in deep-sea cores from off northern Honshu, an inconsistency between the tephrostratigraphy and the FAD of E. huxleyi has been reported. This inconsistency can be explained by poor preservation of calcareous fossils in the deep waters off northern Honshu, which are more corrosive to calcium carbonate than the shallower waters off Shikoku Island. These findings emphasize the importance of cross-checking biohorizons against tephra horizons and of linking tephras between terrestrial and marine sequences to assess the synchronicity of globally correlated age indicators.
•Glass shards in core MD012422 were characterized by compositional analyses.•Tephras with similar shard chemistries were discriminated by the shard morphologies.•All tephras except one from central Honshu were derived from the Kyushu volcanic zone.•Ages of revised tephra horizons are consistent with the reported δ18O stratigraphy.•Ages of the tephra horizons are consistent with reported regional biohorizons.
The sediment sequence from Integrated Ocean Drilling Program (IODP) Site U1304 (53°03.40′N, 33°31.78′W; water depth, 3024 m) on the southern Gardar Drift, North Atlantic Ocean, covers the last ...∼1.8 Myr with a mean sedimentation rate of ∼15 cm/kyr. At Site U1304, paleomagnetic directional and relative paleointensity (RPI) records have been generated for the last ∼1.5 Myr, and benthic oxygen isotope data for the last ∼1 Myr. The age model for Site U1304 was established by matching δ18O and RPI data to calibrated reference records. Prominent intervals of diatom mats at Site U1304 are associated with the latter stages of interglacial marine isotope stages (MIS) 9, 11, 13, 15, 21, 27 and 35, and with the weak glacial of MIS 14. The deposition of diatom mats, and associated diluted magnetic mineral concentrations, leads to weak magnetizations and susceptibilities in these intervals. Comparison of histograms of paleomagnetic directions and RPI from diatom-rich sediments and from surrounding silty clays indicates that, although results from diatom-rich sediments are more scattered, the occurrence of diatom mats does not appreciably distort the paleomagnetic directional and RPI records. Site U1304 sediments record the Matuyama/Brunhes boundary (∼772 ka), the Jaramillo Subchron (∼993–1071 ka) and the Cobb Mountain Subchron (∼1193–1219 ka), as well as three apparent geomagnetic excursions in the Matuyama Chron, interpreted as the “Kamikatsura/Santa Rosa”, “Punaruu”, and “Gardar” excursions, at ∼888 ka, ∼1124 ka, and ∼1463 ka, respectively. The Site U1304 RPI record can be correlated with the PISO-1500 RPI stack and with other high-resolution RPI records from the North Atlantic Ocean. Wavelet analyses performed on the Site U1304 RPI record and a new high-resolution North Atlantic paleointensity stack for the last 1500 kyr (HINAPIS-1500), comprising Ocean Drilling Program (ODP) Sites 983, 984 and IODP Sites U1306 and U1304, did not reveal significant orbital power.
•IODP Site U1304 recorded 5 reversals and 3 possible excursions in the last 1.5 Myr.•Major diatom mat intervals at the site occur during latter stages of interglacials.•Diatom mats dilute magnetic content with little distortion of paleomagnetic records.•New N. Atlantic paleointensity (RPI) stack matches the PISO stack at few kyr scales.•RPI records show high coherence and power at periods of ∼64–100 and ∼256 kyr.
The environmental and climatic evolution of the late Middle Pleistocene to Late Pleistocene of the Garraf Massif (northeastern Iberia) is determined for Marine Isotope Stage 7 (MIS 7) to MIS 3 on the ...basis of a study of the small-vertebrate (amphibian, squamate reptile, insectivore, bat and rodent) assemblages. This paper provides a synthesis of three previously published and one partially published sets of environmental and climatic data from the Middle to Upper Paleolithic sites of Cova del Rinoceront, Cova del Gegant, Cova del Coll Verdaguer and Terrasses de la Riera dels Canyars, all of which are located in the Garraf Massif mountain range. Using the habitat weighting and mutual ecogeographic range methods to reconstruct the environmental and climatic parameters, the results show great variability in the landscape and climate of the area. However, although the human occupation is not intense in the analyzed sites, the various layers of the sites in which the human presence is relatively more intense coincide with landscapes dominated by woodland formations in mild climatic conditions. A comparison of our results with those from other sites with studies of small vertebrates in Greece, Italy, southern France, and the Iberian Peninsula reveals the same pattern, showing that the hominins that inhabited the western Mediterranean region in the late Middle Pleistocene and Late Pleistocene were closely related to forested areas.
•Synthesis of climatic and environment data for Middle-late to late Pleistocene.•Mutual Ecogeographic Range and Habitat weighting used to reconstruct its conditions.•Methods applied in the same way for herpetofauna and small mammal's assemblages.•Results shows a great variability of the landscape and climate of the studied area.
A multi-elevated-temperature post-IR IRSL (MET-pIRIR) protocol, which utilizes the IRSL signals measured by progressively increasing the stimulation temperature from 50 to 300 °C in a step of 50 °C, ...was applied to date the potassium-rich feldspar (K-feldspar) extracts from loess samples at the Luochuan section of the Chinese Loess Plateau. It was observed that the MET-pIRIR ages obtained at elevated-temperatures (250 and 300 °C) are consistent with independent chronological control for the samples from the first loess layer (L1) to the third paleosol layer (S3), which correspond to the marine isotope stages (MIS) 2–9. Our results indicate that the MET-pIRIR protocol can provide reliable ages for the Chinese loess up to ∼300 ka. The results suggest that the MET-pIRIR signal measured at 250 and 300 °C gives the most reliable ages for older samples (>130 ka). For samples below L3, the natural MET-pIRIR signals measured at high temperatures reach the saturation level in dose response curves, suggesting a dating limit of ∼300 ka for the Luochuan loess section.
► We dated the K-feldspar from loess samples at the Luochuan section of the Chinese Loess Plateau. ► The K-feldspar ages are consistent with independent age control for the samples from L1 to L3. ► The MET-pIRIR protocol can provide reliable ages for the Chinese loess up to ∼300 ka.
Clay mineralogy, siliciclastic grain-size, major elements, 87Sr/86Sr, and εNd analyses of deep-sea sediments cored in the north-eastern Bay of Bengal are used to reconstruct evolution of detrital ...sources and sediment transport to the proximal part of the Bengal deep-sea fan during the last climatic cycle. εNd values (−13.3 to −9.7) and 87Sr/86Sr ratios (0.721–0.733) indicate a mixture of sediments originating from the Ganges-Brahmaputra rivers and the Indo-Burman ranges. Interglacial Marine Isotopic Stages (MIS) 5 and 1 are associated with a higher contribution of sediments from the Ganges-Brahmaputra river system than is the case for glacial MIS 6, 4, 3, and 2. Siliciclasitic grain-size combined with Si/Al and Si/Fe ratios indicate coarser glacial sediments with numerous turbidite layers. Glacial turbidite layers display similar clay mineralogical compositions to hemipelagic sediments. Only few of turbidite layers (MIS 6, 4, and 2) are slightly unradiogenic (εNd −13.3), suggesting a higher contribution of Ganges-Brahmaputra river sediments. Independently of changes in the sedimentary sources, the smectite/(illite + chlorite) ratio of cores located on the NE Bengal Fan indicates higher inputs of primary minerals (illite and chlorite) from the highlands of the river basins (relief) during glacial MIS 6, 4, 3, and 2 and an increased contribution of pedogenic minerals (smectite and kaolinite) during interglacial MIS 5 and 1. Maximum smectite/(illite + chlorite) ratios during the warm sub-stages of MIS 5 suggest an intensification of summer monsoon rainfall associated with higher rates of physical erosion of the Indo-Gangetic flood-plain and/or dominant summer hydrological conditions transporting a higher proportion of sediments deriving from the Ganges-Brahmaputra rivers to the NE Bengal Fan. In addition, a higher production of smectite in soils of the Indo-Gangetic flood-plain during periods of intensification of monsoon rainfall cannot be excluded.
•Source of the sediments from the north-eastern part of the Bengal Fan is proposed.•Multi-proxy approach gives information about the link between climate and erosion.•Geochemistry results indicate a mixing source of the sediments in the studied area.•Clay assemblage presents a climatic control during the last 182 kyr BP.•Turbidite activity influence sedimentation rates during glacial periods.
New constraints were set on the age of marine deposits in the Pontine Plain and of the related sea level indicators on the Tyrrhenian Sea coast of central Italy by twelve new 40Ar/39Ar dates on ...detrital sanidine from these deposits. By combining a new geomorphologic analysis and previous morpho-pedo-stratigraphic studies with these geochronological constraints we reconstructed the geometry of four marine terraces and correlated these with the highstands during the marine isotopic stages (MIS) 9.3, 7.5, 5.5 and 5.3.
Results point to a progressive tilting of the terraces, the elevation increasing from the SE to the NW due to differential tectonic uplift that occurred over the last 300 ka. We identified a MIS 9 sea level at 30 - 25 m asl in the northwestern sector, whereas the MIS 7.5 sea level reached a maximum of 24 m asl in the NW and descended to 18 m asl in the central sector. Moderate tilting affected the MIS 5.5 sea level, with an elevation of 12 to 9.5 m asl in between the Anzio and Circeo headlands. Finally, an undeformed MIS 5.3 sea level at ca. 3 m asl is indicated throughout this coastal reach, confirming previous data suggesting a much higher absolute sea level during this highstand with respect to the δ18O-derived predicted level.
•We provide 12 new 40Ar/39Ar dates on a suite of marine terraces in the Pontine Plain.•We correlate these terraces with marine isotopic stages (MIS) 9.3, 7.5, 5.5 and 5.3•We identify sea-level indicators for each one of these isotopic stages.•The MIS 5.5 sea level occurs at 12 to 9.5 an asl as a consequence of tectonic tilting.•We show that the MIS 5.3 sea level occurs at 2–3 m asl throughout this coastal reach.
To refine knowledge about terrace phases and uplift history for a tectonically poor deformed region, we apply the synchronous correlation method to reconstruct the chronology of a poorly constrained ...sequence of raised palaeoshorelines on the Apulian foreland, southern Italy. This work uses new chronological constraints obtained by amino acid racemisation (AAR) and isoleucine/alloisoleucine epimerisation (IE) on Patella spp., Thetystrombus latus (Gmelin), Glycymeris sp., and ostracods and U-series dating on corals Hoplangia durotrix Gosse and Cladocora caespitosa Linneo. This procedure provides a quantitative estimate of the vertical movements and associated rates within a region of the Apulian foreland. The synchronous correlation method uses sea-level highstands and uplift rate(s) as inputs; in particular, for sea-level highstands, the inputs are the age of the highstands and the sea-level elevation of the highstands relative to the present-day sea level. The output is a set of currently expected elevations of each sea-level highstand (the present elevations of palaeoshorelines). We then used regression analysis to assess the robustness between our observed palaeoshorelines and expected elevations of sea-level highstands. Our results show that the best fitting scenario is obtained using the sea-level curves of (i) Waelbroeck et al. (2002) from present to 410 ky BP and (ii) Rohling et al. (2014) from 410 to 590 ky BP as inputs for our synchronous correlation method, with uplift rates ranging from 0.09 mm/y to 0.07 mm/y with a mean value of 0.08 mm/y from 590 ky BP onwards.
We recognised palaeoshorelines in the field belonging to the following highstands: 120 ky BP (MIS 5.5, second peak), 127 ky BP (MIS 5.5, first peak), 212 ky BP (MIS 7.3), 330 ky BP (MIS 9.3), 410 (MIS 11), 525 ky BP (MIS 13.3), and 590 ky BP (MIS 15). Our results show field observations of the reoccupation effect of younger palaeoshorelines over older ones due to the relatively slow uplift rates measured in the investigated area as predicted by our synchronous correlation method. In particular, we show a well-mapped and described reoccupation of the MIS 5.5 palaeoshoreline over the MIS 7.3 palaeoshoreline, constrained by new absolute dating.
In addition, the data from the Apulian foreland suggest an MIS 7.3 highstand close to the present sea level.
•We apply the synchronous correlation method in order to reconstruct palaeoshorelines.•Three palaeoshorelines dating back to two highstand of MIS 5.5•Re-occupation of older palaeoshorelines by younger due to low uplift rates•Sea level for the MIS 7.3 highstand close to the present sea level
This article reviews key data and debates focused on relative sea-level changes since the Last Interglacial (approximately the last 132,000 years) in the Mediterranean Basin, and their implications ...for past human populations. Geological and geomorphological landscape studies are critical to archaeology. Coastal regions provide a wide range of resources to the populations that inhabit them. Coastal landscapes are increasingly the focus of scholarly discussions from the earliest exploitation of littoral resources and early hominin cognition, to the inundation of the earliest permanently settled fishing villages and eventually, formative centres of urbanisation. In the Mediterranean, these would become hubs of maritime transportation that gave rise to the roots of modern seaborne trade. As such, this article represents an original review of both the geo-scientific and archaeological data that specifically relate to sea-level changes and resulting impacts on both physical and cultural landscapes from the Palaeolithic until the emergence of the Classical periods. Our review highlights that the interdisciplinary links between coastal archaeology, geomorphology and sea-level changes are important to explain environmental impacts on coastal human societies and human migration. We review geological indicators of sea level and outline how archaeological features are commonly used as proxies for measuring past sea levels, both gradual changes and catastrophic events. We argue that coastal archaeologists should, as a part of their analyses, incorporate important sea-level concepts, such as indicative meaning. The interpretation of the indicative meaning of Roman fishtanks, for example, plays a critical role in reconstructions of late Holocene Mediterranean sea levels. We identify avenues for future work, which include the consideration of glacial isostatic adjustment (GIA) in addition to coastal tectonics to explain vertical movements of coastlines, more research on Palaeolithic island colonisation, broadening of Palaeolithic studies to include materials from the entire coastal landscape and not just coastal resources, a focus on rescue of archaeological sites under threat by coastal change, and expansion of underwater archaeological explorations in combination with submarine geomorphology. This article presents a collaborative synthesis of data, some of which have been collected and analysed by the authors, as the MEDFLOOD (MEDiterranean sea-level change and projection for future FLOODing) community, and highlights key sites, data, concepts and ongoing debates.
Few continental palaeoenvironmental sedimentary sequences from Southern Europe are long enough to span the last interglacial period (Marine Isotopic Stage-MIS 5), the last glacial cycle (MIS 4 to 2) ...and the Holocene. El Cañizar de Villarquemado (North-Eastern Iberian Peninsula) is an exceptional sedimentary lacustrine sequence spanning the last ca. 135,000 years of environmental change in an area of inland Iberia characterized by Mediterranean climate with strong continentality. We present a multiproxy study which combines palynological, sedimentological and geochemical analyses framed by an independent, robust chronology. Hydrological and climate evolutions were reconstructed by sedimentological and geochemical proxies. Development of wetlands and shallow carbonate lakes support relatively humid conditions during MIS 6, till the onset of MIS 4, and during the Holocene. Palaeohydrological conditions were drier during MIS 5 (dominance of peat environments) than during the Holocene (more frequent carbonate-producing lakes). Sedimentological evidence indicates extremely arid conditions during MIS 3 with greater activity of alluvial fans prograding into the basin. Sedimentary facies variability highlights a large environmental and hydrological variability during MIS 2 and a rapid humidity response to the onset of the Holocene.
Compared to classic Mediterranean sites, we found novel pollen assemblages for the end of MIS 6 and MIS 5 indicating that the vegetation cover was essentially represented by sustained high proportions of continentality-adapted taxa dominated by Juniperus during the relatively humid conditions since MIS 6 till the onset of MIS 4. Higher evapotranspiration in inland Iberia would have increased during periods of higher seasonal insolation maxima, impeding soil development and the usual mesophyte expansion during interglacials observed in other Mediterranean areas. Four main periods of forest development occurred in Villarquemado during MIS 5e, MIS 5c, MIS 5a and the Holocene; secondary peaks occurred also during MIS 3. During colder but still relatively humid MIS 4, junipers and Mediterranean taxa disappear but some mesophytes and cold-tolerant species persisted and Pinus became the dominant tree up to modern times. Pollen assemblages and geochemical data variability suggest a dominant control of seasonality and the impact of North Atlantic dynamics both during MIS 5 (cold events C18-C24) and full glacial conditions (HE and D-O interstadials). At millennial scales, steppe herbaceous assemblages dominated during the extremely arid conditions of MIS 3 and pines and steppe taxa during glacial period MIS 2. Villarquemado sequence demonstrates that the resilient behaviour of conifers in continental areas of inland Southern European regions is key to understand the glacial–interglacial vegetation evolution and to evaluate scenarios for potential impacts of global change.
•Continentality and moisture drove Mediterranean landscapes during last interglacial.•Evapotranspiration impeded soil development and mesophyte expansion in inland Iberia.•The resilient behaviour of conifers is key to evaluate impacts of Global Change.
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