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Establishing the biogenicity of sedimentary surface textures with unresolved microbial origin is critical to any environmental and geobiological interpretation of clastic settings. Here, some Ediacaran wrinkle structures and associated carbonaceous greywacke samples containing mat fragments rich in 'bacteriomorph acritarchs' are investigated. Their biogenicity was evaluated with transmitted light and scanning electron microscopy, epifluorescence and Raman spectroscopy, and confirmed by the presence of distinct cyanobacterial biomarkers. The comparison of results yielded by these techniques validates the use of Raman spectroscopy on Neoproterozoic kerogen (organic‐walled microfossils and amorphous organic material) under low metamorphic conditions. Raman spectrographs also allowed recognition of associated rare‐earth element‐rich phosphate (monazite) and subsidiary metal sulphide concentrations, and interpreted as a result of biosorption and/or mat trapping under normal oxic conditions. These microbial mat features represent cyanobacterial bloom‐forming Bavlinella acritarchs, which characterise eutrophic episodes in a semi‐enclosed retroarc basin sandwiched between an active Cadomian arc and West Gondwana. [ABSTRACT FROM AUTHOR]

Objectives: To present a new dental specimen that will provide additional evidence for a better understanding of early European Upper Pleistocene hominin morphological variability. Materials and Methods: We described the morphology of this human right lower third molar at both the outer enamel surface and the enamel–dentine junction by means of micro‐computed tomography. In order to better understand hominin diversity, our morphological and metrical results were compared with those of other hominins obtained from published research. We provide a direct aspartic acid racemization dating of the molar. Results: The direct dating (104.3 ka) situates the molar within the Marine isotopic stage 5d. The crown dimensions are comparable to those of the Sima de los Huesos sample and modern humans. The combination of a continuous middle trigonid crest and a well‐developed anterior fovea lies within the range of morphological variation reported for Neanderthal lower molars. The distal portion of the molar has a prominent protostylid. Discussion: Crown and root morphology of this molar fits within the Neanderthal morphological pattern. However, both its dimensions and the absence of a hypoconulid tend to position this specimen away from contemporaneous Neanderthals and rather relate it more closely to some Middle Pleistocene populations. Conclusions: A new dental specimen is added to the Iberian Peninsula fossil record from the Marine isotopic stage 5, attesting to some degree of dental variability in the early Upper Pleistocene. [ABSTRACT FROM AUTHOR]

Sedimentological, paleobiological, mineralogical, and geochemical analyses of a sediment core retrieved on the seafront of Cartagena Bay were performed after high-resolution sampling. A wide series of dates obtained through radiocarbon and amino acid racemization proved that the Holocene record on the analyzed core began at ca. 7300 yr cal BP. Reinterpretation of the marine seismic profiles indicated that the beginning of this transgression was channeled along erosive paleochannels excavated on a coastal plain of, at least, MIS5c age. The Holocene paleoenvironmental evolution consisted of a first period marked by marine conditions with strong inputs from a fan delta linked to the reorganized fluvial network that occurred after the sudden rise of the base level, which caused a growing sedimentary prism. Later, the full marine environment was reflected in the development of a Posidonia - Cymodocea meadow hosting a rich biodiversity of marine species (mollusks, foraminifera, ostracoda). Around 3800 yr cal BP, the area underwent a profound change and a silting process started to alter the conditions, turning the area into a paucispecific brackish marsh environment in which mud deposition was dominant. Since Carthaginian times, arrangement works locally affected the record, allowing the arrival of some marine species due to port work (dredging) undertaken to gain depth and showing anthropic influence. [ABSTRACT FROM AUTHOR]

This paper presents a detailed geological and geomorphological analysis of the so‐called givoni (low‐relief, mainly gravelly landforms subparallel to the coastline) associated with the MIS 5 terrace in the northern Gulf of Taranto (southern Italy). These landforms can be interpreted as former beach ridges, swash/drift‐aligned spits, or swash/drift‐aligned barriers (BSBs); thus, givoni are palaeoshoreline indicators. In the study area, recognizing the classic landforms associated with marine terraces, that is, surfaces and scarps, is difficult, as the givoni are often associated and variably combined with surfaces and scarps. Thus, we reconstruct the formation and evolution processes of the MIS 5 marine terrace, including the formation of surfaces, scarps, and BSBs (and the resulting composite landforms), in an overall evolutionary framework based on eustatic oscillations. Then, we reconstruct a complete set of situations in which BSBs form on loose or semiconsolidated substrates in response to eustatic oscillations: (a) BSBs can form during a highstand of a warm stage on previously consolidated sediment; (b) BSBs may represent coastlines formed during sea‐level standstills in the context of a general regressive phase following the highstand peak that created a relict sea cliff; (c) BSBs may represent coastlines formed during a new relative highstand in a warm substage on previously unconsolidated deposits formed during the same stage; and (d) BSBs may be formed by a process similar to that of the previous case, except that the sea level stopped rising against a pre‐existing BSB. [ABSTRACT FROM AUTHOR]

The Las Conchas Mire, at the base of the Cuera Range in Northern Spain, has been regarded as an example of a peatland, where the palaeoclimate variations are obscured by the continuous water runoff--even during drier periods--, the latter being not necessarily accompanied by additional mineral input (Ortiz et al„ 2016), The 320-cm-thick, bryophyte-dominated profile covers a time span of 8000 cal yr BP. The petrographic study of the samples reveals that huminite macerals dominate the profile with liptinite and inertinite yielding typically contents below 3%, except in the bottommost area, where higher content of both maceral groups is observed. This section is also characterized by a fast increase in ash yield towards the bottom, and lower ratio textinite/attrinite representing the phase of depression filling. Once ombrotrophic conditions were established, the maceral composition became more stable. The major component throughout the profile is textinite indicating a high level of tissue preservation as also inferred from predominance of long chain n-alkanoic acids. Three maceral varieties have been counted for textinite (0, A and B) with 0 representing the closest appearance to recent tissues and B the most humified material. The predominant textinite is the A variety, exhibiting high intensity yellow-orange fluorescence. Higher amount of textinite 0 has been recorded in the upper 60 cm of the peat profile suggesting less humified material. The uppermost 20 cm of the profile are clearly enriched in attrinite resulting from tissue destruction in agreement with a drop of the C/N ratio, a bimodal distribution of the n-alkanoic acids with significant presence of short-chain homologues attributed to microbes. This is explained as the result of the mire transformation into a meadow through drainage in the last ca. 200 yr. The homogeneity of the maceral composition throughout the profile supports the findings based on organic geochemical proxies, which suggest a peat profile accumulated during humid periods with short drier periods determined more by the geomorphological setting than the palaeoclimate conditions. [ABSTRACT FROM AUTHOR]

The predominantly carbonate nature of the mountains near the coast of Málaga and Marbella (Costa del Sol, southern Spain) and the presence of springs have favored the formation of travertine buildups during the Quaternary. The geomorphic characteristics of the slopes and the location of the springs have determined the development of three types of travertine growths: (1) spring travertines, located preferentially on the south mountainside, where the slope is steepest; (2) pool-dam-cascade travertines, which form along the north and east edges, far from the carbonate relief and with a gentler slope; and (3) river-valley travertines, formed in the courses of the springs of any sector. Field observations combined with new amino acid racemization (AAR) dating of Helicidae gastropods show that most of the travertine formations are polyphasic and that their development was interrupted by stages of erosion and incision. Five stages of travertine development are evident, most of which are related to warm, moist episodes corresponding to marine oxygen isotope stages (MIS) 7, 5, 3, and 1, although local travertine growth also occurred during MIS 6 and during the transition from MIS 3 to 2. [ABSTRACT FROM AUTHOR]

Here, we sought to reconstruct the Pleistocene and Holocene evolution of Cartagena Bay. Therefore, 16 borehole cores were analysed with the following aims: (1) to define a chronological framework; (2) to obtain data on the palaeoenvironment; and (3) to establish the relationship with human activities, especially focused on the reconstruction of the Carthago Nova (also known as Qart Hadasht) conquest. A total of 147 samples were recovered for amino acid racemisation (AAR) dating; 32 for radiocarbon dating (14C); and 159 for sedimentological, palaeontological, and biomarker determination. These approaches allowed us to elucidate the evolutionary phases of the palaeolandscape in Cartagena. The simultaneous use of AAR and 14C dating allowed the discrimination of spurious ages and the establishment of a chronological scale. During the Marine Isotope Stages (MIS) 7 and 5, the sea level (SL) in Cartagena Bay was almost the same as today. An alluvial plain developed in the northern area, and a delta was formed by an ephemeral river. In contrast, during MIS4, after a fall in SL, a wide sandy coastal plain emerged, leading to the accumulation of colluvial and aeolian deposits. The Holocene transgression was reflected in the hinterland in a late and temporarily floodable marsh fed by alluvial fans and creeks, producing a salinity gradient from freshwater to brackish and saline waters. Along the sea front, the marine influence was evident but not dominant, grading up and landwards to saline and freshwater marshes. Therefore, at the time of Scipio's conquest, the geography of Carthago Nova was quite different from that described by Polybius. The Roman's sudden attack seized Qart Hadasht from the south-west, avoiding the marshy area and not crossing a fast and deep ebb stream as it never existed on the Mediterranean Iberian coast. [ABSTRACT FROM AUTHOR]

The lipid content of three cores from Lake Enol (Picos de Europa National Park, Asturias, Northern Spain) was studied. The n- alkane profiles indicated a major input from terrigenous plants [predominance of high molecular weight (HMW) alkanes] since ca. 1695 AD to the water body, although the uppermost cm revealed a predominance of organic matter (OM) derived from algae, as the most abundant alkane was C 17 . Three units revealing different environmental conditions were defined. Unit A (ca. 1695–1860 AD) in the lowermost parts of ENO13-10 (< 12 cm) and ENO13-15 (< 28 cm) was identified and was characterized by higher OM input and evidence of minimal degradation (high CPI values, predominance of HMW n- alkanoic acids and good correspondence between the predominant n- alkane and n- alkanoic acid chains). These findings could be linked to the Little Ice Age, when cold and humid conditions may have favored an increase in total organic carbon (TOC) and n -alkane and n -alkanoic acid content (greater terrigenous OM in-wash), and may have also reduced bacterial activity. In Unit B (ca. 1860–1980 AD) the lack of correspondence between the n -alkane and n -alkanoic acid profiles of ENO13-10 (12–4 cm) and ENO13-15 (28–8 cm) suggested a certain preferential microbial synthesis of long chain saturated fatty acids from primary OM and/or bacterial activity, coinciding with a decrease in OM input, which could be linked to the global warming that started in the second half of the 19th century. In ENO13-7 the low OM input (low TOC) was accompanied by some bacterial degradation (predominance of HMW n- alkanoic acids but with a bimodal distribution) in the lowermost 16–5 cm. Evidence of considerable phytoplankton productivity and microbial activity was especially significant in Unit C (ca. 1980–2013 AD) identified in the uppermost part of all three cores (5 cm in ENO13-7, 4 cm in ENO13-10 and 8 cm in ENO13-15), coinciding with higher concentrations of n- alkanes and n- alkanoic acids, which were considered to be linked to warmer and drier conditions, as well as to greater anthropogenic influence in modern times. Plant sterols, such as β-sitosterol, campesterol and stigmasterol, were significantly present in the cores. In addition, fecal stanols, such as 24-ethylcoprostanol from herbivores, were present, thereby indicating a continuous and significant pollution input derived from these animals since the 17th century, being more important in the last 20 years. [ABSTRACT FROM AUTHOR]

We reconstructed the palaeoenvironmental conditions of Cartagena Bay during the Holocene after a multidisciplinary study to identify natural variations and the anthropic processes of this coastal area. A total of 119 samples were recovered for amino acid racemization dating, 3 for radiocarbon dating (14C), and four sets of 80 samples for sedimentological and palaeontological determination, mineralogical content, biomarker and trace elements quantification. Two natural scenarios were identified from the variations of n -alkane indices and palaeobiological content. The first period (6650–5750 yr cal BP) was marked by the development of euhaline marine conditions with strong inputs from aquatic macrophytes and high biodiversity. After a hiatus, the area underwent a profound change, becoming a paucispecific brackish marsh environment with increasing inputs from land plants, with possible episodes of emersion with a greater presence from terrestrial gastropods (3600–300 cal yr BP). By combining trace element abundance and stanol distributions, our study also provides a novel approach to identify the predominant influence of anthropogenic factors in the last three millennia in the coastal record of Cartagena Bay. Findings confirmed that Pb mining and metallurgy began during the Bronze Age, with considerable inputs of this heavy metal into the atmosphere during Phoenician, Punic and particularly Roman times compared to the Middle Ages. Pollution by Cu and Zn was also observed during Punic and Roman times, and was first documented in the Middle Ages. In addition, faecal stanols, such as coprostanol, derived mainly from humans, and 24-ethylcoprostanol from herbivores were present, thereby indicating for the first time a continuous presence of human populations and significant pollution input since 3600 yr cal BP, this being greater in the late Bronze Age and Phoenician, Punic and Roman times than during Late Antiquity and the Middle Ages, when the city was in decline. [Display omitted] • Euhaline marine conditions and high biodiversity occurred at 6650–5750 yr. • A paucispecific brackish marsh environment occurred at 3400–300 yr after an hiatus. • Faecal sterols revealed pollution from herbivores and humans since Bronze Age. • Pb–Zn–Cu linked to regional mining-metallurgy since Bronze Age to Middle Ages. [ABSTRACT FROM AUTHOR]

The inorganic content of the well-preserved 3.2-m record of Las Conchas bog (NW Spain), covering 8000 cal yr BP., was analysed. To study natural vs. human contributions, we applied an innovative approach, namely the sequential study of multivariate statistics (factor analysis followed by clustering of the factor score matrix) and enrichment factors (EFs). The increasing weight of potentially toxic elements (PTEs) such as the geochemical association of Zn, Pb and Cd (EFs higher than 10, 20 and 40 in the last two centuries) was revealed, and corroborated by the contrast between the contents of anthropogenic Pb and total Rare Earth Elements (a suitable proxy for natural geogenic supplies). Furthermore, elements such as Hg, Tl and As also showed enrichment in the most recent samples of the study core. Some of them are commonly associated with global atmospheric transport; however, in this case, their increasing contents could also be explained by nearby industrial and mining activities. In summary, severe pollution was observed in the uppermost part of the record, thereby pointing to an important environmental concern. Given that local and regional sources of PTEs, such as mining and heavy industry, especially Zn smelting, were probably the main historical causes of this contamination and that some of these industries are still active, we consider that our findings deserve further attention. Image 1 • Las Conchas bog has a preserved inorganic record of more than 8000 years BP. • Multivariate statistics revealed a notable anthropic input in the last 225 years. • Cd–Zn–Pb and Hg-As high contents mainly related to regional mining & industry. Capsule: Regional industrial and mining sources dramatically accelerated PTEs deposition in the last 225 years in NW Spain. [ABSTRACT FROM AUTHOR]

The Tajo Basin is one of the richest in Mg-clays known around the world. Mg-bentonites, kwon as pink clays and green clays, alter in the Intermediate Unit of the Miocene sediments. In this work, a new approach to the genesis of these bentonites is performed by studying for the first time the biomarkers present in these clays in relation to the mineralogy and geochemistry, as well as using discriminatory criteria between green and pink clays. Samples were collected at a quarry of Mg-bentonites, in the proximities of Esquivias (Toledo, Spain). Mineralogical characterization and semi-quantification (X-ray diffraction (XRD)) allowed a well-defined classification according to the mineralogical content of the samples to be established, differentiating four associations. Geochemical analyses are clearly linked to the mineralogy and provide criteria to differentiate the genesis of the materials studied. In this regard, green clays are interpreted as having a more detrital character than pink clays, which present a more authigenic character. Biomarkers (n-alkanes and n-alkanoic acids) were studied, not showing a clear link with the mineralogy as in the case of the geochemistry, but providing interesting information about the origin and degradation of the organic matter. Pink clays have higher contents in biomarkers than green clays, providing a discriminative criterion. [ABSTRACT FROM AUTHOR]

• Based on alkane indices, three geochemical units (GU) were identified. • GUs represent major contribution of aquatic macrophytes or terrestrial plants. • Paleoenvironmental episodes (PE) produced oscillations in the marsh water level. • PEs were related to sea level and climatic changes, and recent tectonics. • Emersion led to increased amounts of short-chain and branched fatty acids. We reconstructed the paleoenvironmental conditions of the Mazarrón Basin during MIS 7 and MIS 1 based on their alkane and fatty acid contents, their mineralogy and the fossil content of an amino-acid-dated sediment sequence. The n- alkane and fatty acid indices proved to be excellent paleoenvironmental proxies for studying the paleo-hydrogeological and paleoclimatological evolution of this marshland. Three geochemical units (GUs) were identified from the abundance of the C 25 n -alkane and the ACL, TAR HC and P aq values, confirming the importance of phases with terrestrial plant input or aquatic macrophyte predominance. These GUs were used to define three paleoenvironmental episodes (PEs) during MIS 7. In PE7.1, the contribution of algal and aquatic macrophytes predominated in a temporarily flooded saline muddy plain. In PE7.2, the major contribution was from aquatic macrophytes (flooded marsh), although it was marked by episodes of emersion with greater terrestrial contribution. At the top of the MIS 7 record (PE7.3), there was a significant reduction in the water depth, with the main input deriving from terrestrial plants in a muddy alluvial plain. Six PEs were established during MIS 1 (Holocene), of which three predominately received organic matter derived from aquatic macrophytes, while the major contribution in the other three came from terrestrial plants. The two sets of PEs were linked to episodes of increased and decreased water level, respectively. This interpretation is consistent with the characteristics of the sediment facies, with PE1.1, 1.3 and 1.5 corresponding to a marsh with deeper water and a greater input of detrital materials, and PE1.2, 1.4 and 1.6 to a shallow environment with carbonates and gypsum deposits. Direct marine influence was limited, so the oscillations in the water level in the marsh were likely to be more related to climatic changes (drier/wetter phases) and recent tectonics than to large changes in sea level. Emersion led to degradation of the organic matter and enrichment in short-chain and branched saturated fatty acids. [ABSTRACT FROM AUTHOR]

We determined the lipid distributions ( n- alkanes, n- alkan-2-ones, n- alkanoic acids), total organic carbon (TOC), total nitrogen (TN), Ca/Mg and ash content in Las Conchas mire, a 3.2 m deep bryophyte-dominated mire in Northern Spain covering 8000 cal yr BP. Bog conditions developed in the bottom 20 cm of the profile, and good preservation of organic matter (OM) was inferred from n- alkanoic acid distribution, with the exception of the uppermost 20 cm (last ca. 200 yr). Microbial synthesis of long chain saturated fatty acids from primary OM likely produced a dominance of short chain n- alkanoic acids with a bimodal distribution, as well as the lack of correspondence between the n -alkane and n -alkanoic acid profiles in the upper 20 cm. This was accompanied by an increase in ash content, a decrease in TOC and variation in n- alkane ratios, thereby suggesting significant changes in the mire, namely drainage and transformation to a meadow, in the last ca. 200 yr. The distribution of n- alkan-2-ones indicated an increase in bacterial source from the bottom of the record to 94 cm, whereas their distribution in the upper part could be attributed mainly to plant input and/or the microbial oxidation of n- alkanes. The different n- alkane proxies showed variations, which we interpreted in terms of changes in vegetation (Sphagnum vs. non-Sphagnum dominated phases) during the last 8000 cal yr BP. C 23 was the most abundant homolog throughout most of the record, thereby suggesting dominant humid conditions alternating with short drier phases. However, such humid conditions were not linked to paleoclimatic variation but rather to geomorphological characteristics: Las Conchas mire, at the base of the Cuera Range, receives continuous runoff—even during drier periods—which is not necessarily accompanied by additional mineral input to peat, producing the development of Sphagnum moss typical of waterlogged ecotopes and damp habitats. Thus, although geochemical proxies indicated an ombrotrophic regime in the mire, geomorphological characteristics may make a considerable contribution to environmental conditions. [ABSTRACT FROM AUTHOR]