Seismotectonic versus man-induced morphological changes in a cave on the Arrábida chain (Portugal)

Distinctions between cave morphologies originating from seismic or active tectonics and those generated by natural clastic breakdown or by human activity must be made using unambiguous interpretative criteria.Easily accessible caves in particular, which may have been visited for centuries or millennia, or caves located near engineering works or quarries using great quantities of explosives, may have broken speleothems, breakdowns or detachment joints unrelated to seismic events or tectonic movements.Zambujal cave lies near neotectonic and seismic structures associated with a Plio-Quaternary 200 m uplift of the Arrábida chain and has suffered impacts resulting from quarrying, followed by possible vandalism. It is thus an example for which it is difficult to decipher morphological agents as there is the possibility that identical forms have been generated by several causes, which may have repeated at different episodes of its evolution. However, a careful morphological interpretation makes it possible to accept the existence of two seismic episodes, an “ancient” one and a “modern” one. The detection of other episodes between these is only possible using absolute dating.     

Seismotectonic versus man-induced morphological changes in a cave on the Arrábida chain (Portugal)

Abstract

Distinctions between cave morphologies originating from seismic or active tectonics and those generated by natural clastic breakdown or by human activity must be made using unambiguous interpretative criteria.

Easily accessible caves in particular, which may have been visited for centuries or millennia, or caves located near engineering works or quarries using great quantities of explosives, may have broken speleothems, breakdowns or detachment joints unrelated to seismic events or tectonic movements.

Zambujal cave lies near neotectonic and seismic structures associated with a Plio-Quatemary 200 m uplift of the Arrábida chain and has suffered impacts resulting from quarrying, followed by possible vandalism. It is thus an example for which it is difficult to decipher morphological agents as there is the possibility that identical forms have been generated by several causes, which may have repeated at different episodes of its evolution. However, a careful morphological interpretation makes it possible to accept the existence of two seismic episodes, an “ancient” one and a “modern” one. The detection of other episodes between these is only possible using absolute dating. © Elsevier, Paris     

Cattle-based livelihoods,changes in the taskscape,and human–bear conflict in the Ecuadorian Andes

Cattle-raising, especially for dairy, has expanded in the Ecuadorian Andes since the late 1990s as smallholding farmers have shifted their livelihood activities away from crop-based agriculture due to changes in climate, market conditions, and rural out-migration. Non-migrants constructing cattle-based livelihoods are turning to cattle as the basis for “viable” livelihoods in order to remain in depopulating rural parishes. Non-migrant farmers express ideals such as autonomy and tranquility as reasons for their attachment to rural places. In turn, their livelihood activities remake these places materially. Drawing on Tim Ingold’s conceptualization of taskscape and landscape, I argue that cattle-based livelihoods create a taskscape prone to human–wildlife conflict. Since 2009, residents have reported dozens of Andean bear attacks on cattle. Cattle are vulnerable capital assets. They represent both an investment with daily and weekly dividends over many years, in the form of milk, and a long-term form of wealth storage. The turn to cattle-based livelihoods in this region has thus heightened human–bear conflict. The phenomenon of the human–bear conflict is therefore a product of shifting livelihoods and accompanying changes in the taskscape. This analysis demonstrates the importance of listening to narratives of place attachment and accounting for the cultural logics of livelihood choices when considering interventions to address human–wildlife conflict.     

Potential environmental impact at São Domingos mining district (Iberian Pyrite Belt,SW Iberian Peninsula): evidence from a chemical and mineralogical characterization

São Domingos like other long-term activity mines of the Iberian Pyrite Belt (IPB) dating back to pre-Roman times, is supposed to produce considerable amounts of mining wastes which cause significant downstream negative environment impact related to the acid mine drainage (AMD) production and high content of potentially toxic metals and metalloids in Chanza and Guadiana Rivers. The AMD production of a given mining waste depends on the ratio of its acid production to neutralizing phases. In this work, a chemical and mineralogical characterization of the sulphide-rich wastes from São Domingos has been developed to discriminate which residues are the main sources of AMD generation. A total of 47 representative samples of the different residue types were collected to estimate their possible contamination hazards through detailed studies of (1) for a mineralogical characterization: reflected-light optical microscope, scanning electron microscope (SEM) and XRD analysis; and (2) for a chemical characterization: bulk-rock analysis. AMD prediction by the standard acid-base accounting method (ABA) was used in order to determine the acidification potential of each residue type. This study also offers an estimation of the contribution of toxic elements to the environment, being thus, a base for future remediation actions at São Domingos and other abandoned massive sulphide mines within the IPB.     

New and exceptional discovery in the Upper Cretaceous of the Iberian Peninsula: the palaeontological site of “Lo Hueco”, Cuenca,Spain

The palaeontological site of “Lo Hueco” was discovered in Cuenca, Spain, in 2007. It includes a stratigraphic interval in “Garumn” facies belonging to the upper part of the Villalba de la Sierra Formation. A succession of versicolor marly mudstone levels (V, G1, R1, G2, R2 and M) can be observed at the site studied. This succession is partially modified by a sandy channel structure (C) and by a sulphated interval (S). The C structure and the G1, G2 and R2 (lower part) levels have an extremely rich and varied fossil concentration and have provided to date more than 8500 macroremains. These are mainly from vertebrates, but also from plants and invertebrates. In general, vertebrates are represented by mineralized bones with an early infilling of gypsum, a ferruginous crust, and a secondary precipitation of gypsum; invertebrates by internal moulds; and plants by carbonized remains. Among the vertebrates, titanosaur dinosaurs (some of them with partially articulated skeletons) are by far the most common representatives, although lepisosteid fishes, bothremydid turtles, squamate lizards, eusuchian crocodiles, and ornithischian and theropod dinosaurs are also well represented. The relative stratigraphic position and the palaeontological content of this site allow to attribute it to the upper Campanian-lower Maastrichtian. Interpretation of its materials suggests a near coast muddy flood plain crossed by distributary sandy channels environment, exposed to brackish to fresh water aquatic influence.     

Reassessment of the ‘Abbevillien’ in the perspective of new discoveries from the Lower Palaeolithic and Quaternary sites of Abbeville (Somme,northern France)

North-West Europe yields few traces of early human occupation, in particular for the Acheulean. In this context, the Somme Valley in northern France offers a route to Britain during various Pleistocene low sea levels, and has provided numerous evidence of Lower Palaeolithic human occupation through fieldwork initiated during the 19th century. These localities are associated with the original definition in the 1930s by the French prehistorian Abbé Henri Breuil of the ‘Abbevillien’ (Abbevillian facies), based on lithic pieces including crudely made bifaces recovered in particular in some famous key localities of Abbeville, Carpentier, Léon and Moulin Quignon quarries. The history of the term and its definition subsequently gave rise to debates concerning the chronocultural framework of Palaeolithic assemblages among the scientific community of prehistorians over time, from Jacques Boucher de Perthes, Gabriel de Mortillet, Geoffroy d'Ault du Mesnil, Victor Commont, Henri Breuil and François Bordes. New investigations at these three localities, all associated with the High Terrace of the Somme system, pushed back the age of the expansion of the Acheulean both in northern France and in Western Europe to c. 670–650 000 years. They imply that early hominins were able to settle in North-West Europe during both climatic temperate and cold phases. Our work, including new excavations and associated field observations of the three Abbeville localities involved at the onset of the controversy, allows a re-examination of the Abbevillian and contributes to the discussion of the history of Prehistoric Science and the Earliest ‘Acheuleans’ in North-West Europe.     

Holocene environmental changes and human impact in the northern Swiss Jura as reflected by data from the Delémont valley

The construction of the A16-Transjurane motorway revealed evidence of Holocene sediment sequences in the Delémont valley (Canton of Jura, Switzerland). Certain processes begin during the Younger Dryas. Pine forests dominate this cold period, which was unfavourable for pedogenesis; they remain throughout the first half of the Holocene. The meandering river system then becomes stable for more than four millennia. The first signs of human impact on the vegetal cover begin to appear around 3,500 cal BC (Middle Neolithic). An increase in hydric activity occurs between 3,600 and 2,500 cal BC. However, the earliest evidence of the cultivation of cereals dates only to about 2,000 cal BC (Early Bronze Age). Extensive forest clearing and the emergence of cultivated plants occur after 1,400 cal BC. On the cleared slopes the soil erodes and at their foot colluvium deposits accumulate. The densification of the settlement from the Late Bronze Age (1,350–800 cal BC) until the beginning of the Iron Age (800–650 cal BC) contributes to alluvial destabilization. A palaeosol has been identified in all of the Holocene deposits in the valley. The deforestation intensifies between 400 and 100 cal BC while hydric activity decreases. The first centuries of our era record very limited pedo-sedimentary phenomena. However, human presence becomes less marked after 350 cal AD. The slopes are stabilized and the soil develops. From 550 cal AD, an important increase in hydric activity takes place, a probable consequence of a wet fluctuation in the climate. Contemporary forest clearing causes deep gullies. After 750 cal AD, drier conditions set in. This period of stability, marked by occasional rises in the water level, continues until 1,250–1,300 cal AD (Late Middle Ages). Then superficial flows resume and entrenchment of the main waterways occurs, combined consequences of the Little Ice Age and the upsurge in human activity.     

Neoproterozoic–Cambrian synsedimentary magmatism in the Central Iberian Zone (Spain): geology,petrology and geodynamic significance

Petrographic, geochemical and field studies in low grade metamorphic areas (Ciudad Rodrigo-Hurdes-Sierra de Gata domain, CRHSG, central-western Spain) show that Neoproterozoic-Lowermost Cambrian series in the Central Iberian Zone (CIZ) record two kinds of provenance sources including: (1) detrital material derived from recycled orogens and (2) a Cadomian coeval juvenile contribution that governs their isotopic signature. Evidence of magmatism contemporaneous with Neoproterozoic-Cambrian sedimentation is provided by the presence of coherent, massive volcanic rocks (metabasalts, metaandesites, and metarhyolites), volcaniclastic shales, sandstones, conglomerates and breccias. The appearance of volcanogenic lithic fragments and crystals mixed in different proportions with siliciclastic constituents and also present within calcareous components in the sedimentary succession, reinforces this evidence. Although most of the selected volcanic and volcaniclastic samples appear to show tholeiitic affinity, some of them display calc-alkaline affinity. Different trace element ratios, such as Sm/Nd, Nb/Yb and Ta/Yb, suggest a magmatic evolution in the same tectonic setting. The geochemical results reported here support the existence of an active geodynamic setting as a direct contributor to the synsedimentary and magmatic content of the Neoproterozoic–Lowermost Cambrian successions in the CIZ. In particular, the relatively high Nd _(T) values and the high range of f ^Sm/Nd ratios are consistent with an active margin during the Neoproterozoic–Early Cambrian. The existence of tectonic activity is also confirmed by the presence of synsedimentary deformation and volcanic rocks. All of these traits favour a geodynamic model in which the Iberian Cadomian segment represented in the CIZ would have been part of an active northern margin of Gondwana, with an associated magmatic arc and related basins during Neoproterozoic–Lower Cambrian times. A proposed link between the Ossa Morena and the Central Iberian Zones might account for late Cadomian pull-apart basins developed on both sides of the magmatic arc, sharing the same scenario and involving similar magmatic activity during the Neoproterozoic–Cambrian transition.

Jurassic and Cretaceous radiolarian assemblages from the Bornova mélange in northern Karaburun Peninsula (western Turkey) and its connection to the İzmir–Ankara mélanges

Two large blocks of red bedded chert identified within the Late Cretaceous–Paleocene Bornova mélange in northern Karaburun Peninsula yielded Jurassic (late Bathonian–early Oxfordian) and Cretaceous (middle–late Albian) radiolarian assemblages. These new data confirm the correlation of the Bornova mélange with the Bornova Flysch Zone (BFZ) and the ?zmir–Ankara mélanges. A review of all previously obtained ages in chert blocks of the BFZ and the ?zmir–Ankara mélanges is provided in order to strengthen this correlation.     

From sprawl to compactness and back: population dynamics (1848–2011) and the economic structure of a Mediterranean city

In the recent decades southern European cities experienced morphological changes and a demographic transition towards zero (or negative) growth and aging. Population dynamics shifted from the impressive growth of the post-industrial period into recent de-concentration processes determining the spillover of commercial and residential settlements across the surrounding rural areas. Based on long-term demographic data, the present study hypothesizes that urban expansion did not follow a one-way linear path from compactness to dispersion while reflecting differentiated growth patterns based on the specific socioeconomic context at the local scale. Along a sufficiently long time period non-linear expansion waves alternating settlement densification and scattering are expected to be found especially in complex urban contexts such as those developed in the Mediterranean region. This hypothesis was tested for a paradigmatic case study in southern Europe (Athens, Greece) using demographic data covering 160 years (1848–2011). Urban growth in Athens was assessed through the analysis of long-term census data made available on a district level. These data provide information on the spatial distribution of resident population and characterize distinct expansion waves according to the dominant socioeconomic context. Results of the study were discussed in the light of the debate on future development of the Mediterranean cities and the (changing) economic relations with the surrounding region.     

Formation of helictite in the cave Dragon Belly (Sardinia,Italy)—Microstructure and incorporation of Mg,Sr, and Ba

In the Dragon Belly cave helictites, a special type of irregular speleothem, are found, which grew on stalactites in all vertical and horizontal directions without any affinity to gravity. Microstructural and mineralogical analyses of this stalactite–helictite system indicate that its evolution is initiated by clogging of the central stalactite channel at its tip, probably when the cave was flooded by muddy water. Clogging caused the formation of secondary channels (≈0.2 mm in diameter) for water passage through the outer surface of the stalactite, where helictites start to grow. The secondary channel passes into the central channel of the helictite.The helictites consist of stacked idiomorphic calcite crystals with uniform orientation. Growth of calcite is essentially controlled by water transfer through the central channel and via canalicules (narrow channels of ≈0.05 mm in diameter) following the crystal boundaries of the calcite mesocrystal induced by capillary hydrostatic forces. At straight parts of the helictites calcite crystals are almost uniform in size, but at bended parts crystals are significantly smaller inside (≤0.1 mm in length) than outside of the bend (≤0.5 mm). It is proposed that the difference in calcite volume (larger crystals) vs. the inside of the bend leads to a helix form, which explains the origin of the term helictite.The Sr and Ba concentrations measured by laser ablation along helictites can be explained by cation incorporation during calcite precipitation close to equilibrium. Dilution effects caused by seasonality control the elemental distribution in the helictite, which result in a positive correlation between Sr and Ba. Variability of Mg is unrelated with Sr and Ba, and is probably due to the incongruent dissolution of Mg–calcite from the host rock.     

New data on the magnetostratigraphy of the Jurassic–Cretaceous boundary interval,Nordvik Peninsula (northern East Siberia)

The results of this study were used to identify a reversed polarity magnetozone, referred to as M17r, in Berriasian sections of the Nordvik Peninsula (northern East Siberia) within the normal polarity magnetozone (M18n) from previous studies. The new magnetozone embraces the Volgian–Ryazanian boundary (Chetaites chetae/C. sibiricus zonal boundary). It was also found that the former magnetozone M17r at Nordvik, which includes the C. sibiricus/Hectoroceras kochi zonal boundary should correspond to magnetozone M16r. Using magnetostratigraphic and biostratigraphic criteria proves that the Boreal C. sibiricus Zone is correlated with at least the major part of the Tethyan Tirnovella occitanica Zone, and the Boreal H. kochi Zone is correlated with the lower part of the Malbosiceras paramimounum Subzone of the Tethyan Fauriella boissieri Zone.     

Proximal–distal facies relationships and sedimentary processes in a storm dominated carbonate ramp (Kimmeridgian,northwest of the Iberian Ranges,Spain)

Facies analysis of the upper Kimmeridgian rocks in the outcrops located near Ricla (Zaragoza province, northeast Spain) and the integration of the resultant data in a broader context (the northern part of the Iberian Basin), has produced two general models showing the facies distribution and the processes that controlled the sedimentation in the Kimmeridgian carbonate ramp. Using these two models the transition from shallow to relatively deep environments of the carbonate ramp is examined in detail. Model 1 corresponds to the development of a mixed carbonate-siliciclastic ramp during a slow rise and stillstand of sea level (Sequence 1-HST), whereas Model 2 represents the growth of a pure carbonate ramp during a rapid rise of sea level (Sequence 2-TST).Carbonate production was higher in the shallow ramp domains (coral reefs and oolitic shoals in Model 1 and reefs in Model 2) than in deeper domains, where there is no indication of significant pelagic or benthic production. The activity of unidirectional return flows induced by winter storms and hurricanes, played an important role in the redistribution of the sediment across the ramp, generating different coarse-grained deposits. In the inner and mid-ramp settings dunes, lower scale bedforms and tempestites occur in Model 1, and storm lobes, bars and tempestites in Model 2. Moreover, a significant bulk of the carbonate mud produced in shallow areas would eventually be resedimented in the outer ramp as suspended load in the density currents. Stillstand of sea level in Model 1 involved a rapid progradation of the inner and proximal mid-ramp carbonate and siliciclastic facies. The rapid relative sea level rise of Model 2 is determined by the dominance of the carbonate facies and by the presence of aggradational geometries in the transitional area between shallow and deep-ramp domains. The presence of relatively thick sections in the outer-ramp settings (instead of condensed sections, as observed in Model 1) during times of sea level rise (Model 2) can mainly be explained by the increase of the shallow production in the reef dominated areas.     

Detrital and volcanic zircon U–Pb ages from southern Mendoza (Argentina): An insight on the source regions in the northern part of the Neuquén Basin

The infill of the Neuquén Basin recorded the Meso-Cenozoic geological and tectonic evolution of the southern Central Andes being an excellent site to investigate how the pattern of detrital zircon ages varies trough time. In this work we analyze the U–Pb (LA–MC–ICP–MS) zircon ages from sedimentary and volcanic rocks related to synrift and retroarc stages of the northern part of the Neuquén Basin. These data define the crystallization age of the synrift volcanism at 223 ± 2 Ma (Cerro Negro Andesite) and the maximum depositional age of the original synrift sediments at ca. 204 Ma (El Freno Formation). Two different pulses of rifting could be recognized according to the absolute ages, the oldest developed during the Norian and the younger during the Rhaetian–Sinemurian. The source regions of the El Freno Formation show that the Choiyoi magmatic province was the main source rock of sediment supply. An important amount of detrital zircons with Triassic ages was identified and interpreted as a source area related to the synrift magmatism. The maximum depositional age calculated for the Tordillo Formation in the Atuel-La Valenciana depocenter is at ca. 149 Ma; as well as in other places of the Neuquén Basin, the U–Pb ages calculated in the Late Jurassic Tordillo Formation do not agree with the absolute age of the Kimmeridgian–Tithonian boundary (ca. 152 Ma). The main source region of sediment in the Tordillo Formation was the Andean magmatic arc. Basement regions were also present with age peaks at the Carboniferous, Neoproterozoic, and Mesoproterozoic; these regions were probably located to the east in the San Rafael Block. The pattern of zircon ages summarized for the Late Jurassic Tordillo and Lagunillas formations were interpreted as a record of the magmatic activity during the Triassic and Jurassic in the southern Central Andes. A waning of the magmatism is inferred to have happened during the Triassic. The evident lack of ages observed around ca. 200 Ma suggests cessation of the synrift magmatism. The later increase in magmatic activity during the Early Jurassic is attributed to the onset of Andean subduction, with maximum peaks at ca. 191 and 179 Ma. The trough at ca. 165 Ma and the later increase in the Late Jurassic could be explained by changes in the relative convergence rate in the Andean subduction regime, or by the shift to a more mafic composition of the magmatism with minor zircon fertility.     

The Teggiolo zone: a key to the Helvetic–Penninic connection (stratigraphy and tectonics in the Val Bavona,Ticino, Central Alps)

The Teggiolo zone is the sedimentary cover of the Antigorio nappe, one of the lowest tectonic units of the Penninic Central Alps. Detailed mapping, stratigraphic and structural analyses, and comparisons with less metamorphic series in several well-studied domains of the Alps, provide a new stratigraphic interpretation. The Teggiolo zone is comprised of several sedimentary cycles, separated by erosive surfaces and large stratigraphic gaps, which cover the time span from Triassic to Eocene. At Mid-Jurassic times it appears as an uplifted, partially emergent block, marking the southern limit of the main Helvetic basin (the Limiting South-Helvetic Rise LSHR). The main mass of the Teggiolo calcschists, whose base truncates the Triassic–Jurassic cycles and can erode the Antigorio basement, consists of fine-grained clastic sediments analogous to the deep-water flyschoid deposits of Late Cretaceous to Eocene age in the North-Penninic (or Valais s.l.) basins. Thus the Antigorio-Teggiolo domain occupies a crucial paleogeographic position, on the boundary between the Helvetic and Penninic realms: from Triassic to Early Cretaceous its affinity is with the Helvetic; at the end of Cretaceous it is incorporated into the North-Penninic basins. An unexpected result is the discovery of the important role played by complex formations of wildflysch type at the top of the Teggiolo zone. They contain blocks of various sizes. According to their nature, three different associations are distinguished that have specific vertical and lateral distributions. These blocks give clues to the existence of territories that have disappeared from the present-day level of observation and impose constraints on the kinematics of early folding and embryonic nappe emplacement. Tectonics produced several phases of superimposed folds and schistosities, more in the metasediments than in the gneissic basement. Older deformations that predate the amplification of the frontal hinge of the nappe generated the dominant schistosity and the km-wide Vanzèla isoclinal fold.     

Geology and mineralization of the Dayin’gezhuang supergiant gold deposit (180 t) in the Jiaodong Peninsula,China: A review

The Dayin’gezhuang gold deposit is located in the central part of the Zhaoping Fault metallogenic belt in the Jiaodong gold province —the world ’s third-largest gold metallogenic area. It is a typical successful case of prospecting at a depth of 500‒2000 m in recent years, with cumulative proven gold resources exceeding 180 t. The main orebodies (No. 1 and No. 2 orebody) generally have a pitch direction of NNE and a plunge direction of NEE. As the ore-controlling fault, the Zhaoping Fault is a shovel-shaped stepped fault, with its dip angle presenting stepped high-to-low transitions at the elevation of −2000‒0 m. The gold mineralization enrichment area is mainly distributed in the step parts where the fault plane changes from steeply to gently, forming a stepped metallogenic pattern from shallow to deep. It can be concluded from previous studies that the gold mineralization of the Dayin’gezhuang gold deposit occurred at about 120 Ma. The ore-forming fluids were H₂O-CO₂-NaCl-type hydrothermal solutions with a medium-low temperature and medium-low salinity. The H-O isotopic characteristics indicate that the fluids in the early ore-forming stage were possibly magmatic water or mantle water and that meteoric water gradually entered the ore-forming fluids in the late ore-forming stage. The S and Pb isotopes indicate that the ore-forming materials mainly originate from the lower crust and contain a small quantity of mantle-derived components. The comprehensive analysis shows that the Dayin ’gezhuang gold deposit was formed by thermal uplifting-extensional tectonism. The strong crust-mantle interactions, large-scale magmatism, and the material exchange arising from the transformation from adakitic granites to arc granites and from the ancient lower crust to the juvenile lower crust during the Early Cretaceous provided abundant fluids and material sources for mineralization. Moreover, the detachment faults formed by the rapid magmatic uplift and the extensional tectonism created favorable temperature and pressure conditions and space for fluid accumulation and gold precipitation and mineralization.©2022 China Geology Editorial Office.     

Thrusting and sinistral wrenching in a pre-Eocene HP-LT Caribbean accretionary wedge (Samaná Peninsula,Dominican Republic)

The North Caribbean margin is an example of an oblique convergence zone where the currently exposed HP–LT rocks are systematically localised close to strike-slip faults. The petrological and structural study of eclogite and blueschist facies rocks of the peninsula of Samaná (Hispaniola, Dominican Republic) confirms the presence of two different metamorphic units. The former diplays low metamorphic grade (Santa Barbara unit), characterized by the assemblage albite - lawsonite (7.5 ± 2 kbar and 320 ± 80 °C). The latter (Punta Balandra unit), thrust over the first unit towards the NW, and is characterized by the occurrence of blueschist and eclogite facies assemblages (13 ± 2 kbar and 450 ± 70 °C), within oceanic metasediments. The isothermal retrograde evolution occurred in epidote-blueschist facies conditions (9 ± 2 kbar and 440 ± 60 °C). The late greenschist facies evolution is contemporaneous with conjugate NW–SE extension and E–W strike-slip faulting. This late extension is for regional dome and basin structures. According to their lithotectonic, structural and metamorphic characteristics, the metamorphic nappe stack of Samaná may be interpreted as a fragment of an accretionary wedge thrust onto the North American continental shelf. Evolution of the wedge was associated with the active subduction of the North American plate, under the Greater Antilles arc, at the level of the Puerto Rico trench. During active Late Cretaceous convergence, the HP rocks were initially exhumed, within the accretionary prism, by thrusting parallel to the NE–SW direction of convergence. Subsequently, during the Eocene collision between the Caribbean plate and the North American margin, the installation of a transtensive regime of E–W direction supports the local development of conjugate extension of NW–SE direction that facilitated the final phase of exhumation of the HP rocks.     

Relation between the variations in the global surface temperature,El Niño/La Niña phenomena,and the Atlantic Multidecadal Oscillation

We analyzed directed couplings between the variations in the global surface temperature and modes of the natural climatic variability: the El NiñoLa Niña (ENSO) quasi-periodical phenomena and the long-period Atlantic Mutidecadal Oscillation (AMO) based on the data for 1870–2014. According to the quantitative estimates based on the monthly and annual mean data, the initial data, and the 10-year mean remote data, the most pronounced impact of the ENSO on the global surface temperature and the AMO was found. A weaker bidirectional coupling between the global surface temperature and the AMO is also pronounced. The analysis using running windows revealed an alternating effect of the ENSO and AMO on the variations in the global surface temperature related to the AMO phases.