Description: Publication date: Available online 27 December 2014 Source: Earth-Science Reviews Author(s): Stefano Furlani , Andrea Ninfo The empirical and conceptual relationships between Earth surface processes and global changes are very complex. The concept that “the present is the key of the future” implies that we know enough the present to be able to extend our knowledge forward to focus on the future. Field and remote observations on the present-day Earth surface processes represent the methodological instruments for the forecasting. At the end of the 1980s, the scientific community predicted a significant increase of global warming followed by changes in the trends of related surface processes. Some processes, such as the Arctic and Antarctic snow melting are now accelerating and even irreversible, thus these trends show that we are now in an ‘out of scale’ discontinuity moment. Present-day measures and observations could be scarcely significant and may add uncertainty in the prediction of future trends. The ‘out-of-scale’ trend raises a fundamental question regarding the present, since it may provide a new angle of thought for contemporary theoretical approaches. The need for reducing the uncertainty in the trends of future processes requires a deep rethinking of the current paradigms in order to consider also the ‘out of scale‘ trends.

Description: Publication date: Available online 17 December 2014 Source: Earth-Science Reviews Author(s): Rowan C. Martindale , Frank A. Corsetti , Noel P. James , David J. Bottjer The Late Triassic was a pivotal period in reef evolution, but the majority of information about reef ecology during this time comes from buildups in the Alps (e.g., the Tethys Ocean). Recent studies of reefs in western North America have recognized unique ecologies along the eastern margin of the Panthalassa Ocean. Although there are numerous (twenty-five) localities with putative reef builders, only four buildups had syndepositional relief and a rigid framework (i.e. true reefs). The most paleo-northern true reefs were microbial patch reefs with only a few large skeletal bioconstructors; hypercalcified sponges and spongiomorphs built the mid-latitude reefs, with secondary microbial encrustation and branching, phaceloid Retiophyllia corals. Corals are the primary bioconstructors in Panthalassa’s most paleo-equatorial reefs and calcareous microbes are sparse. When all reefal deposits are analyzed, the N-S gradient is also present, with microbial and bivalve deposits in the north, sponge-coral deposits in the mid latitudes, and coral deposits near the equator. This ecological gradient is not apparent in the Tethys Ocean. Tethyan reefs thrived in oligotrophic, tropical waters without strong latitudinal gradients; by contrast, paleoceanographic considerations suggest that cool, nutrient-rich waters swept south along the western North American borderlands in the Late Triassic. The eastern boundary current is interpreted to have created a strong north-south differentiation of environments in northeastern (NE) Panthalassa that was manifested in both the biotic and abiotic characteristics of eastern Panthalassic reefs. Reefs from equatorial Panthalassa are similar to Tethyan reefs (warm-water, photozoan, coral reef structures), whereas higher paleo-latitude reefs from Panthalassa are interpreted as cool-water (heterozoan) buildups, with abundant calcareous microbes, diminutive biocalcifiers, and few large, framework-building corals.

Description: Publication date: Available online 13 December 2014 Source: Earth-Science Reviews Author(s): Olaf Nehlich Sulfur isotope analysis of archaeological materials provides information on past ecosystems, paleo-diets, migration and mobility. This review covers the geochemical background, including the variability of sulfur isotope compositions in the geo-, hydro-, and biosphere. Then, a substantive review of archaeological studies is undertaken to introduce this new marker for archaeological sciences and demonstrate its possible applications for future research.

Description: Publication date: Available online 13 December 2014 Source: Earth-Science Reviews Author(s): Hong Yan , Willie Soon , Yuhong Wang High-resolution late Holocene climate records that can resolve seasonality are essential for confirming past climatic dynamics, understanding the late 20th century global warming and predicting future climate. Here a new composite record of the sea surface temperature, SST, variation in the northern South China Sea (SCS) during the late Holocene is constructed by combining seven seasonally-resolved coral and T. gigas Sr/Ca-based SST time-windows with the instrumental SST record from modern interval between 1990 and 2000. This composite multi-proxy marine record, together with the reconstructions from mainland China and tropical western Pacific, indicates that the late Holocene warm periods, the Roman Warm Period (RWP) and Medieval Warm Period (MWP), were prominently imprinted and documented in the climatic and environmental history of the East Asia-Western Pacific region. Meanwhile, substantial and significant SST seasonality variations during the late Holocene were observed in the composite record. The observed increase in seasonality (or amplitude of seasonal cycles) during the cold periods around our study area was probably caused by the different amplitudes between winter versus summer SST variations in northern SCS, with much larger SST variation during winters than during summers for the late Holocene. In addition, the distinctive warm, cold and neutral climatic episodes identified in our northern SCS composite SST record correspond well with other paleo reconstructions from mainland China and especially well with the Northern Hemisphere-wide composites by Moberg et al. (2005) and Ljungqvist (2010). The overall agreement however also calls for more information and insights on how seasonal temperatures and their ranges vary on decadal-centennial timescales.

Description: Publication date: Available online 10 December 2014 Source: Earth-Science Reviews Author(s): Z.T. Yao , X.S. Ji , P.K. Sarker , J.H. Tang , L.Q. Ge , M.S. Xia , Y.Q. Xi Coal fly ash, an industrial by-product, is derived from coal combustion in thermal power plants. It is one of the most complex anthropogenic materials, and its improper disposal has become an environmental concern and resulted in a waste of recoverable resources. There is a pressing and ongoing need to develop new recycling methods for coal fly ash. The present review first describes the generation, physicochemical properties and hazards of coal fly ash at the global level, and then focuses on its current and potential applications, including use in the soil amelioration, construction industry, ceramic industry, catalysis, depth separation, zeolite synthesis, etc. Finally, the advantages and disadvantages of these applications, the mode of fly ash utilization worldwide and directions for future research are considered.

Description: Publication date: Available online 8 December 2014 Source: Earth-Science Reviews Author(s): Fang Hao , Xuefeng Zhang , Cunwu Wang , Pingping Li , Tonglou Guo , Huayao Zou , Yangming Zhu , Jianzhang Liu , Zhongxian Cai This article discusses the role of methane in thermochemical sulfate reduction (TSR), the fate of TSR-derived CO 2 and the effect of TSR on reservoir porosity and permeability, and the causes of the anomalously high porosity and permeability in the Lower Triassic soured carbonate gas reservoirs in the northeast Sichuan Basin, southwest China. The Lower Triassic carbonate reservoirs were buried to a depth of about 7000 m and experienced maximum temperatures up to 220 °C before having been uplifted to the present-day depths of 4800 to 5500 m, but they still possess porosities up to 28.9% and permeabilities up to 3360 md. The present-day dry gas reservoirs evolved from a palaeo-oil accumulation and experienced varying degrees of TSR alteration as evidenced from the abundant sulfur-rich solid bitumens and varying H 2 S and CO 2 concentrations. TSR occurred mainly within the oil and condensate/wet gas windows, with liquid hydrocarbons and wet hydrocarbon gases acting as the dominant reducing agents responsible for sulfate reduction, sulfur-rich solid bitumen and H 2 S generation, and calcite precipitation. Methane-dominated TSR was a rather late event and had played a less significant role in altering the reservoirs. Intensive H 2 S and CO 2 generation during TSR resulted in calcite cementation rather than carbonate dissolution, which implies that the amount of water generated during TSR was volumetrically insignificant. 13 C-depleted CO 2 derived from hydrocarbon oxidation preferentially reacted with Ca 2 + to form isotopically light calcite cements, and the remaining CO 2 re-equilibrated with the 13 C-enriched water-rock systems with its δ 13 C rapidly approaching the values for the host rocks, which accounted for the observed heavy and relatively constant CO 2 δ 13 C values. The carbonate reservoirs suffered from differential porosity loss by TSR-involved solid bitumen generation and TSR-induced calcite and pyrite precipitation. Intensive TSR significantly reduced the porosity and permeability of the intervals expected to have relatively high sulfate contents (the evaporative-platform dolostones and the platform-margin shoal dolostones immediately underlying the evaporative facies). Early oil charge and limited intensity of TSR alteration, together with very low phyllosilicate content and early dolomitization, accounted for the preservation of anomalously high porosities in the reservoirs above the palaeo-oil/water contact. A closed system seems to have played a special role in preserving the high porosity in the gas zone reservoirs below the palaeo-oil/water contact. The closed system, which is unfavorable for deep burial carbonate dissolution and secondary porosity generation, was favorable for the preservation of early-formed porosity in deeply buried carbonates. Especially sucrosic and vuggy dolostones have a high potential to preserve such porosity.

Description: Publication date: Available online 4 December 2014 Source: Earth-Science Reviews Author(s): A. Myrttinen , V. Becker , J.A.C. Barth

Description: Publication date: Available online 2 December 2014 Source: Earth-Science Reviews Author(s): S. Tavani , F. Storti , O. Lacombe , A. Corradetti , J.A. Muñoz , S. Mazzoli Aesthetically appealing thrust systems and related large-scale anticlines, in both active and fossil foreland fold-and-thrust belts, and the economic potential associated with them, have captured the interest of structural geologists for many decades. As a consequence, a large amount of data on sub-seismic deformation patterns from thrust-related anticlines is available in the literature. We provide a review of deformation pattern templates from field data in foreland fold-and-thrust-belts and show that the most frequent trends of sub-seismic syn-orogenic deformation structures hosted in km-scale thrust-related folds frequently and paradoxically indicate a syn-thrusting strike-slip stress field configuration, with a near-vertical σ 2 and a sub-horizontal σ 3 , rather than a contractional one where the latter is expected to be the vertical principal axis of the stress ellipsoid. This apparent inconsistency between sub-seismic syn-orogenic deformation structures and stress field orientation is here named “the σ 2 paradox”. Field data support a possible explanation of the paradox, provided by the major role played by inherited early-orogenic extensional deformation structures on thrust fault nucleation. Nucleation of major thrusts and their propagation is facilitated and driven by the positive inversion and linkage of the early-orogenic sub-seismic extensional inheritance developed in the foreland basin. This process eventually leads to the development of large reverse fault zones and can occur both in contractional and strike-slip stress field configurations.

Description: Publication date: Available online 29 November 2014 Source: Earth-Science Reviews Author(s): Nicole J. Bayliss , Kevin T. Pickering The middle Eocene deep-marine Morillo System is up to ~ 260 m thick and is the penultimate deep-marine sand-prone system in the Ainsa Basin, Spanish Pyrenees. It comprises the proximal parts of three structurally confined, coarse-grained and channelised mid-slope / canyon to lower-slope submarine fans (designated the Morillo I–III fans). Their constituent channels appear to be low- to moderate-sinuosity channels with widths estimated in the range of 600 m to the order of 1 km, and depths typically several tens of metres or more. Locally, the presence of metre-scale gravel-rich and sandy barforms is consistent with either relatively sinuous thalweg channels or side- and mid-channel bars within a more braided-like channel complex. The abundance of pebble-rich deposits throughout the Morillo System is interpreted to reflect a response to increased gradients in the staging area for sediment gravity-flows and mass wastage, which also may have been linked to a fall in relative base level as the Ainsa thrust-top (piggyback) basin narrowed and was uplifted between the tightening Boltaña, Añisclo and Mediano anticlines (submarine growth structures). As the shallow-marine and non-marine source area was degraded and the sandy fans were abandoned, , up to several hundred metres of very fine- and fine-grained, thin- and very thin-bedded turbidites and hemipelagic sediments mantled the coarser-grained Morillo deposits. This change in depositional style is interpreted as a response to a reduction in seafloor gradients during a phase of increased tectonic shortening across the Ainsa Basin, thereby permitting the growth of the final structurally confined system, the Guaso System, as low-gradient submarine fans in the Ainsa Basin.

Description: Publication date: Available online 27 November 2014 Source: Earth-Science Reviews Author(s): Jun Shen , Shane D. Schoepfer , Qinglai Feng , Lian Zhou , Jianxin Yu , Huyue Song , Hengye Wei , Thomas J. Algeo The lastest Permian mass extinction (LPME) coincided with major changes in the composition of marine plankton communities, yet little is known about concurrent changes in primary productivity. Earlier studies have inferred both decreased and increased productivity in marine ecosystems immediately following the end-Permian crisis. Here, we assess secular and regional patterns of productivity variation during the crisis through an analysis of the burial fluxes of three elemental proxies: total organic carbon (TOC), phosphorus (P), and biogenic barium (Ba bio ). Primary productivity rates appear to have increased from the pre-crisis Late Permian through the Early Triassic in many parts of the world, although the South China Craton is unusual in exhibiting a pronounced decline at that time. Most of the 14 Permian-Triassic study sections show concurrent increases in sediment bulk accumulation rates, suggesting two possible influences linked to subaerial weathering rate changes: (1) intensified chemical weathering, resulting in an increased riverine flux of nutrients that stimulated marine productivity, and (2) intensified physical weathering, leading to higher fluxes of particulate detrital sediment to continental shelves,thus enhancing the preservation of organic matter in marine sediments. An additional factor, especially in the South China region, may have been intensified recycling of bacterioplankton-derived organic matter in the ocean-surface layer, reducing the export flux rather than primary productivity per se . The ecosystem stresses imposed by elevated fluxes of nutrients and particulate sediment, as well as by locally reduced export fluxes of organic matter, may have been important factors in the ~ 2- to 5-million-year-long delay in the recovery of Early Triassic marine ecosystems.