Abstract In this chapter, we analyse the influence of the Carpathian Mountains on the variability of stable isotopes in precipitation by employing a combination of observed and model data. Overall, the mean value of the stable isotopes in precipitation over the Carpathian Mountains, based on observational data, was −9.8‰ for δ 18 O and −68.6‰ for δ 2 H. The local meteoric line, using all samples from the study sites, was δ 2 H = 7.65 × δ 18 O + 5.82. The simulated δ 18 O, based on the ECHAM5-wiso isotopes enable model, showed good agreement with the observed isotopic data. By comparing all the monthly values of the observed isotopic data from all analysed stations and the corresponding model data, a correlation coefficient of 0.76 ( n = 455, p < 0.001) was obtained. The spatial distribution of the simulated δ 18 O values in precipitation had the lowest values over the Romanian Carpathian Mountains and the highest values over the extra-Carpathian area, with the maximum in southeastern Romania. This pattern was strongly influenced by the Carpathian Mountains orography. Using the simulated δ 18 O data, we show that the spatial distribution of the δ 18 O values increases with temperature and decreases with altitude and latitude (−0.5‰ for δ 18 O per degree of latitude). The continental gradient is characterized by a polynomial trend of the second degree in the form of a large-open ‘U’ shape, and the general pattern of the δ 18 O values follows the spatial distribution of the Carpathian Mountains.

Abstract: In 2014, a joint American Association for Petroleum Geologists/Society for Sedimentary Geology (AAPG/SEPM) sponsored Hedberg Conference was convened in Banff, Alberta, Canada, to investigate the impact of latitude on sedimentary systems and the facies models that geologists use to explain outcrop, core, and subsurface observations. This research conference, entitled Latitudinal Controls on Stratigraphic Models and Sedimentary Concepts , investigated the range of depositional systems from shallow to deep marine, and carbonates to clastics, in order to answer the question: Are current concepts and models biased toward mid- and low-latitude systems? The goals of the research symposium were (1) to identify differences in stratigraphic models and sedimentary concepts that arise due to differences in latitude and (2) to search for insights that may be applicable for subsurface interpretations. The articles included in this volume represent a cross-section of the work presented at the conference. Also included are abstracts of the remaining presentations.

Abstract: Approximately 22 Gt of siliciclastic sediment are delivered to the coastal ocean each year across the Earth’s latitude-controlled climate zones. Latitude effects are seen as controls on physical and biogeochemical weathering and thus sediment production; latitude effects also influence precipitation and wind patterns and impact sediment transport through, for example, river-water density and thus through the particle settling velocities of the suspended load. Glacial transport of sediment, including subglacial processes, meltwater, and iceberg rafting, dominates polar regions (10% of land surfaces). Subpolar regions (21% of the global land surface) include many nonglacial environments receiving low intensity rainfall and with low levels of sediment production (physical weathering) and fluvial transport. Their coastal regions are dominated by storm waves modulated by seasonal sea ice. Temperate regions (14%) are zones of moderate sediment production and fluvial transport, regional pockets of eolian transport, and coastal zones highly influenced by storm waves under the westerlies. The subtropical regions (18%) experience high rates of sediment production, moderate rates of precipitation, high rates of eolian transport via the trade winds (North Africa accounts for the majority of the global dust flux), and coastal zones heavily influenced by both swells and storm waves. The tropical region comprises the largest land mass (37%), with very high rates of precipitation (via the InterTropical Convergence Zone [ITCZ]) and sediment production (from biogeochemical weathering), high rates of fluvial clay and silt and sand transport, moderate levels of eolian transport, and swell-dominated coasts. Preservation of woody debris in the tropics is much smaller than in other climatic zones. Tropical river basins can produce and transport 2.5 times more sediment than a similar scale basin located in a temperate region and 12 times more sediment than a similar scale Arctic basin. Both eolian and glacial transport rates were an order of magnitude larger under ice age conditions, and such conditions repeatedly occurred during the past several million years.

Abstract: A common belief about tidal sedimentation is that tides are always larger near the equator and negligible at high latitudes. This belief appears to be based on equilibrium tidal theory that predicts the existence of two ocean–surface bulges centered at low latitudes; however, it is a misconception because this theory is a poor model for real-world tides. Instead, the tide behaves as a set of shallow-water waves that are guided around the world by the continents. Tidal ranges and tidal-current speeds increase as the tidal wave propagates onto and across continental shelves; especially large ranges and fast currents can occur in coastal embayments and in straits that join two larger bodies of water. Models of real-world tides today demonstrate that tides in shallow water (<100 m) have amplitude peaks at 50° N to 70° N and 50° S to 60° S that are associated with especially wide continental shelves and coastal embayments in which the tidal wave is close to resonance. The small tides characterizing most polar areas today are the result of local geomorphic features: the Arctic Ocean is too small to have its own tide and has only a small connection to the Atlantic Ocean that prevents effective northward propagation of the tidal wave, and Antarctica has narrow and deep continental shelves that do not accentuate the tide. Nevertheless, there are local areas in both the Arctic and Antarctic with favorable geomorphology that have macrotidal ranges. Thus, the latitudinal distribution of large tides is contingent on the plate-tectonic and sea-level history of the earth and changes over geologic time as the configuration of the ocean basins and the geometry of the flooded shelves change. The latitudinal variation of the strength of the Coriolis effect has a second-order influence on tidal dynamics, with the degree of tidal-range asymmetry across a basin potentially being larger at higher latitudes. The offshore extent of large coastal tidal ranges decreases at higher latitudes because the increased Coriolis effect leads to the tidal wave being more strongly banked-up against the shoreline. Diurnal, topographically trapped vorticity waves that can generate large tidal currents in shelf-edge water depths are also limited to middle to high latitudes. The presence of ice in polar areas also has an influence on tidal dynamics. Sea ice causes a small decrease in tidal range, whereas thick, floating ice shelves can cause dramatic increases in tidal range and tidal-current speeds, at least locally, as a result of the decrease in the cross-sectional area of the water beneath the ice shelves. Because coastal sedimentation is controlled by the relative importance of tidal currents and waves, the abundance of tide-dominated deposits might not reflect perfectly the latitudinal distribution of large tides. Thus, the small size of waves in the equatorial zone appears to cause preferential development of tide-dominated coastal zones near the equator, whereas wave dominance might be higher at midlatitudes because of the higher level of storminess, regardless of the latitudinal distribution of large tides.

Abstract: Comparison of modern and ancient river deposits shows that both seasonally and interannually highly variable discharge results in distinct sedimentary facies and architecture in the monsoonal and subtropical river deposits, as compared to the perennial precipitation zone rivers. The monsoon zone and subtropical river deposits share most facies and architectural characteristics. The differences are mainly limited to biogenic and pedogenic features, such as in-channel vegetation and vegetation-induced sedimentary structures in rivers in subhumid subtropics. Extremely flashy rivers in arid and semiarid subtropics with highly intermittent precipitation also stand apart by the resemblance with megaflood deposits due to the dominance of Froude supercritical flow sedimentary structures and rapid deposition of suspended sediment. The distinct sedimentary characteristics of the monsoonal and subtropical rivers can be used as a climate proxy. However, they primarily reflect the precipitation pattern, rather than specific latitude or climate zone. Moreover, differences in past climates, as compared to the modern conditions, cause variability in the latitudinal distribution of monsoonal and subtropical precipitation zones throughout the geological history. Arctic rivers also experience seasonally highly variable discharge and display sedimentary characteristics that are partially similar to those of the monsoon zone and subtropical rivers.

Abstract: Using a script that automatically calculates sinuosity and radius of curvature for multiple bends on sinuous channel centerlines, we have assembled a new data set that allows us to reevaluate the relationship between latitude and submarine channel sinuosity. Sinuosity measurements on hundreds of channel bends from nine modern systems suggest that there is no statistically significant relationship between latitudinal position and channel sinuosity. In addition, for the vast majority of submarine channels on Earth, using flow velocities that are needed to transport the coarse-grained sediment found in channel thalwegs, estimates of the curvature-based Rossby number are significantly larger than unity. In contrast, low flow velocities that characterize the upper parts of turbidity currents in submarine channels located at high latitudes can easily result in Rossby numbers of less than one; this is the reason why levee deposits are often highly asymmetric in such channels. However, even in channels with asymmetric levees, the sinuosity of the thalweg is often obvious and must have developed as the result of an instability driven by the centrifugal force. Analysis of a simple centerline-evolution model shows that the increase in channel curvature precedes the increase in sinuosity and that low sinuosities are already associated with large curvatures. This suggests that the Coriolis effect is unlikely to be responsible for the low sinuosities observed in certain systems.

Abstract: Criteria for recognizing a high-paleolatitude context for sedimentary successions are not widely established. Herein, we provide a facies analysis of the Permian succession of the high-paleolatitude Denison Trough in the southwestern Bowen Basin of Queensland, eastern Australia, and we use this analysis to highlight criteria that may be used to diagnose a high-paleolatitude context in this and other successions. A unified facies scheme for several formations, combining sedimentological and ichnological criteria, recognizes both deltaic and nondeltaic facies within the succession. Whereas a full array of deltaic facies is evident, ranging from distal prodelta to coastal plain, a more limited array of nondeltaic facies is recognized, ranging from shelfal to lower shoreface. The dominance of deltaic facies in the succession suggests that coastlines were overwhelmingly deltaic in aspect. The absence of middle and upper (nondeltaic) shoreface deposits suggests that shallow-water settings were constantly under physico–chemical stresses associated with deltaic efflux, and/or that such deposits were excised by transgressive ravinement following deposition. Deltas were mostly arcuate in planform, consistent with strong wave influence, although some show a more irregular or lobate plan morphology, suggesting significant fluvial influence. Four intervals within the Permian succession (coded P1 to P4) preserve evidence of formation under the direct or indirect (glaciomarine) influence of glacial ice. Palpable evidence of the high-paleolatitude context of the succession is preserved only in these intervals, most commonly in the form of dropstones, glendonite pseudomorphs after ikaite, gravel-grade clasts with modified shapes, and diamictites. In addition to vertical changes into and out of glacial intervals, paleolatitudinal changes in glacially influenced facies are evident across the 25- to 30-degree meridional transect from the Bowen Basin south to the Tasmanian Basin. Outside of glacial intervals P1 to P4, there are few sedimentological or ichnological indicators of high-paleolatitude deposition. Facies characteristics of deposition under glacial influence are therefore crucial to diagnosing the high-paleolatitudinal context of this and other successions.