Exploring seven hundred years of transhumance,climate dynamic,fire and human activity through a historical mountain pass in central Spain

A high-altitude peat sequence from the heart of the Spanish Central System (Gredos range) was analysed through a multi-proxy approach to determine the sensitivity of high-mountain habitats to climate, fire and land use changes during the last seven hundred years, providing valuable insight into our understanding of the vegetation history and environmental changes in a mountain pass close to a traditional route of transhumance. The pollen data indicate that the vegetation was dominated by shrublands and grasslands with scattered pines in high-mountain areas, while in the valleys cereals, chestnut and olive trees were cultivated. Strong declines of high-mountain pines percentages are recorded at 1540, 1675, 1765, 1835 and 1925 cal AD, which may be related to increasing grazing activities and/or the occurrence of anthropogenic fires. The practice of mountain summer farming and transhumance deeply changed and redesigned the landscape of the high altitudes in central Spain (Gredos range) since the Middle Ages, although its dynamics was influenced in some way by climate variability of the past seven centuries.     

Changing human-environment interactions in medium mountains: the Apuseni Mts (Romania) as a case study

The study of human-environment relationships in mountain areas is important for both theoretical and practical reasons, as many mountain areas suffer similar problems, such as depopulation, unemployment and natural hazards. Medium mountains constitute a special case within mountains, because they are more populated but less attractive as tourist destinations than high mountains. In this context, the Apuseni Mts (Romania) are considered as a case study. In this paper, we apply GIS-based, quantitative methods to characterize the strength and dynamics of human-environment interactions, taking into consideration some environmental factors (elevation, relative height, slope, river distance, lithology, land cover, natural attractions) as well as historical population and recent tourism data. We found that population density has strong (r ²>0.8) relationships with all relief factors (elevation, relative height, slope, river distance), and that best-fit functions are nonlinear. We outlined the varying demographic scenarios by elevation zones and interpreted the historically switching sign of population change versus elevation relationship. We demonstrated that lithology also has an impact on the spatial distribution of population, although it is not independent from the relief effect. The land cover of the mainly cultural landscape is very strongly correlated with relief parameters (especially slope), which suggests good adaptation. We pointed out the dominance of karst objects in the natural tourism potential of the Apuseni Mts and also explored further components of real tourism (spas, heritage, towns). Finally, we concluded that the environmental settings investigated do in fact constrain the spatial framework of society, but socio-economic changes in history can be explained from the side of society, which conforms to the theory of cultural possibilism.     

Sequence hierarchy in a Mesoproterozoic interior sag basin: from basin fill to reservoir scale,the Tombador Formation,Chapada Diamantina Basin,Brazil

The Tombador Formation exhibits depositional sequence boundaries placed at the base of extensive amalgamated fluvial sand sheets or at the base of alluvial fan conglomeratic successions that indicate basinward shifts of facies. The hierarchy system that applies to the Tombador Formation includes sequences of different orders, which are defined as follows: sequences associated with a particular tectonic setting are designated as ‘first order’ and are separated by first‐order sequence boundaries where changes in the tectonic setting are recorded; second‐order sequences represent the major subdivisions of a first‐order sequence and reflect cycles of change in stratal stacking pattern observed at 10² m scales (i.e., 200–300 m); changes in stratal stacking pattern at 10¹ m scales indicate third‐order sequences (i.e., 40–70 m); and changes in stratal stacking pattern at 10⁰ m scales are assigned to the fourth order (i.e., 8–12 m). Changes in palaeogeography due to relative sea level changes are recorded at all hierarchical levels, with a magnitude that increases with the hierarchical rank. Thus, the Tombador Formation corresponds to one‐first‐order sequence, representing a distinct intracratonic sag basin fill in the polycyclic history of the Espinhaço Supergroup in Chapada Diamantina Basin. An angular unconformity separates fluvial‐estuarine to alluvial fan deposits and marks the second‐order boundary. Below the angular unconformity the third‐order sequences record fluvial to estuarine deposition. In contrast, above the angular unconformity these sequences exhibit continental alluvial successions composed conglomerates overlain by fluvial and eolian strata. Fourth‐order sequences are recognized within third‐order transgressive systems tract, and they exhibit distinct facies associations depending on their occurrence at estuarine or fluvial domains. At the estuarine domain, they are composed of tidal channel, tidal bar and overlying shoreface heterolithic strata. At the fluvial domain the sequences are formed of fluvial deposits bounded by fine‐grained or tidal influenced intervals. Fine grained intervals are the most reliable to map in fourth‐order sequences because of their broad laterally extensive sheet‐like external geometry. Therefore, they constitute fourth‐order sequence boundaries that, at the reservoir approach, constitute the most important horizontal heterogeneity and, hence, the preferable boundaries of production zones. The criteria applied to assign sequence hierarchies in the Tombador Formation are based on rock attributes, are easy to apply, and can be used as a baseline for the study of sequence stratigraphy in Precambrian and Phanerozoic basins placed in similar tectonic settings.     

The sedimentary and tectonic evolution of the Amur River and North Sakhalin Basin: new evidence from seismic stratigraphy and Neogene–Recent sediment budgets

The North Sakhalin Basin in the western Sea of Okhotsk has been the main site of sedimentation from the Amur River since the Early Miocene. In this article, we present regional seismic reflection data and a Neogene–Recent sediment budget to constrain the evolution of the basin and its sedimentary fill, and consider the implications for sediment flux from the Amur River, in particular testing models of continental‐scale Neogene drainage capture. The Amur‐derived basin‐fill history can be divided into five distinct stages: the first Amur‐derived sediments (>21–16.5 Ma) were deposited during a period of transtension along the Sakhalin‐Hokkaido Shear Zone, with moderately high sediment flux to the basin (71 Mt year^?1). The second stage sequence (16.5–10.4 Ma) was deposited following the cessation of transtension, and was characterised by a significant reduction in sediment flux (24 Mt year^?1) and widespread retrogradation of deltaic sediments. The third (10.4–5.3 Ma) and fourth (5.3–2.5 Ma) stages were characterised by progradation of deltaic sediments and an associated increase in sediment flux (48–60 Mt year^?1) to the basin. Significant uplift associated with regional transpression started during this time in southeastern Sakhalin, but the north‐eastward propagating strain did not reach the NE shelf of Sakhalin until the Pleistocene (<2.5 Ma). This uplift event, still ongoing today, resulted in recycling of older deltaic sediments from the island of Sakhalin, and contributed to a substantially increased total sediment flux to the adjacent basinal areas (165 Mt year^?1). Adjusted rates to discount these local erosional products (117 Mt year^?1) imply an Amur catchment‐wide increase in denudation rates during the Late Pliocene–Pleistocene; however, this was likely a result of global climatic and eustatic effects, combined with tectonic processes within the Amur catchment and possibly a smaller drainage capture event by the Sungari tributary, rather than continental‐scale drainage capture involving the entire upper Amur catchment.     

Unraveling the Peruvian Phase of the Central Andes: stratigraphy,sedimentology and geochronology of the Salar de Atacama Basin (22°30–23°S), northern Chile

The Salar de Atacama Basin holds important information regarding the tectonic activity, sedimentary environments and their variations in northern Chile during Cretaceous times. About 4000 m of high‐resolution stratigraphic columns of the Tonel, Purilactis and Barros Arana Formations reveal braided fluvial and alluvial facies, typical of arid to semi‐arid environments, interrupted by scarce intervals with evaporitic, aeolian and lacustrine sedimentation, displaying an overall coarsening‐upward trend. Clast‐count and point‐count data evidence the progressive erosion from Mesozoic volcanic rocks to Palaeozoic basement granitoids and deposits located around the Cordillera de Domeyko area, which is indicative of an unroofing process. The palaeocurrent data show that the source area was located to the west. The U/Pb detrital zircon geochronological data give maximum depositional ages of 149 Ma for the base of the Tonel Formation (Agua Salada Member), and 107 Ma for its middle member (La Escalera Member); 79 Ma for the lower Purilactis Formation (Limón Verde Member), and 73 Ma for the Barros Arana Formation. The sources of these zircons were located mainly to the west, and comprised from the Coastal Cordillera to the Precordillera. The ages and pulses record the tectonic activity during the Peruvian Phase, which can be split into two large events; an early phase, around 107 Ma, showing uplift of the Coastal Cordillera area, and a late phase around 79 Ma indicating an eastward jump of the deformation front to the Cordillera de Domeyko area. The lack of internal deformation and the thicknesses measured suggest that deposition of the units occurred in the foredeep zone of an eastward‐verging basin. This sedimentation would have ended with the K‐T phase, recognized in most of northern Chile.     

Problems of Paleogene–Neogene stratigraphy of the Zerkal’naya depression,East Sikhote Alin

The Paleogene–Neogene stratigraphic scale of the Zerkal’naya River basin is modified with account for new isotopic and paleobotanical data. It is established that the Tadushi Formation and underlying volcanics, which were previously considered as representing transitional Cretaceous–Paleocene strata, are separated in the section of the Ustinovka quarry by a significant stratigraphic hiatus. According to the new data, the volcanics and the Tadushi Formation are established as Campanian and Late Paleocene in age, respectively. The Bogopol Formation in the type section is dated back to the Middle–Late Paleocene. The Svetlyi Formation is now considered to be Early Eocene in age, rather than Late Eocene–Oligocene as previously thought. A new variant of the stratigraphic scale is proposed for the Paleogene–Neogene deposits of the Zerkal’naya depression.     

Yakchi chert–volcanogenic Formation—fragment of the Jurassic accretionary prism in the Central Sikhote-Аlin,Russian Far East

The Yakchi chert–volcanogenic formation is differentiated at the base of the stratigraphic succession in the Khor-Tormasu subzone of the Central Sikhote-clin structural–formational zone or the Samarka terrane of the Jurassic accretionary prism. The paper considers the results of biostratigraphic study of its deposits and petrogeochemical studies of its basalts. A tectonically disrupted sequence of the Yakchi Formation is restored on the basis of fossil conodonts and radiolarians, and its Late cermian–Middle Jurassic age is determined. The authors interpret the resulting stratigraphic succession in terms of changing depositional settings on the moving oceanic plate and recognize events of the ocean history recorded in it. Chert accumulated on the oceanic plate in pelagic canthalassa/caleopacifica from the Late cermian through to the Middle Jurassic. Deposition of siliceous claystone in the Late cermian–Early Triassic reflects the decline in productivity of radiolarians and a long anoxic event in Panthalassa. Chert accumulation resumed in the Triassic and persisted in the Jurassic, and it was interrupted by the eruption of basalts of different nature. Formation of the Middle–Late Triassic oceanic intraplate basalts likely occurred on the thick and old oceanic lithosphere and that of the Jurassic basalts on the thin and newly created lithosphere. In the Middle Jurassic, chert accumulation was replaced by accumulation of tuffaceous siltstone at a subduction zone along the csian continental margin. The middle Bathonian–early Callovian age of this siltstone closely predates accretion of the Yakchi Formation. The materials of the upper layer of the oceanic plate that formed over 100 million years in different parts of the ocean and on the lithospheric fragments of different ages were accreted to the continental margin. The bulk of the accreted material consists of oceanic intraplate basalts, i.e., fragments of volcanic edifices on the oceanic floor. accretion of this western part of the Khor-Tormasu subzone occurred concurrently with accretion of the southeastern part of the Samarka subzone in Primorye, which clarifies the paleotectonic zonation of the Central Sikhote-Alin accretionary prism. The cataclastic gabbroids and granitoids, as well as the clastic rocks with shallow-marine fossils in the Khor-Tormasu subzone, are considered as possible analogues of the Okrainka-Sergeevka allochthonous complex.     

Characterization of fresh and weathered petroleum for potential impacts to soil fertility

In many petroleum-producing regions, there are not adequate controls to prevent pipeline breaks and spills, and thus soil is frequently contaminated with petroleum hydrocarbons. Different petroleum oil compounds may produce negative impacts on soil fertility. In this study, four fresh crudes, a weathered petroleum, and oils from bioremediated and burned sites were investigated (specific gravities 0.83–1.27). Fourier transform infrared spectroscopy revealed three predominant polar functional groups to be more plentiful in the heavier crudes. The relative abundance of these groups was used to calculate an index that was directly correlated with specific gravity (R ² = 0.9960) and the percent of asphaltene plus (polars + resins) fractions in the oil (R ² = 0.9643). This index correlated exponentially to the water repellency caused by petroleum in an alluvial soil (R ² = 0.9928). Furthermore, extra-heavy oil at a concentration of 10,000 ppm, the maximum allowable oil concentration in the soil that is within regulatory norms in many US states and other countries, and with a specific gravity >1.002, showed severe water repellency. This study presents an alternative for determining soil remediation criteria based on the API gravity of the oil rather than the C-range of the hydrocarbon mixtures, simplifying analytical methods and systematically studying the interaction between the kinds of petroleum mixtures and potential impacts to soil fertility.     

Activated sludge acclimation for toluene and DEHP degradation in a two-phase partitioning bioreactor

The effect of activated sludge acclimation on the biodegradation of toluene in the presence of a biodegradable non-aqueous phase liquid, di (2-ethylhexyl) phthalate (DEHP), in a two-phase partitioning bioreactor was characterized. The influence of the presence of DEHP, at a ratio of 0.1 % (volume ratio), and of the acclimation of activated sludge (AS) on the biodegradation of hydrophobic VOC was studied. AS was acclimated to both toluene and DEHP simultaneously. Using acclimated cells, 73 and 96 % improvement of the mean biodegradation rates was recorded for toluene and the organic solvent (DEHP), respectively, if compared to the values recorded in the absence of acclimation, during tests performed in Erlenmeyer flasks. Degradation rates were further improved by the use of acclimated AS in a reactor with a large head space; degradation yields for toluene and DEHP were above 99 and 89 %, respectively.