Palynofacies and paleoenvironment of the Early Cretaceous deposits in the KoppehDagh Basin, Iran

The Sarcheshmeh and Sanganeh formations are the Lower Cretaceous deep marine sequences of the Koppeh-Dagh sedimentary basin, which revealed a diverse assemblage of dinoflagellates. The paper discusses palynostratigraphy, palynofacies and palaeoenvironment of these rock units in a borehole drilled in the eastern part of this basin. Ninety-five ditch-cutting samples were prepared and studied palynologically, which resulted in recognition of 76 species of dinoflagellate cysts belonging to 29 genera. The recorded assemblages are in accordance with the Odontochitina operculata Zone suggesting a Barremian?–Aptian age for the formations. Palynological data extracted led to identification of five palynofacies types based on the categories of Tyson (1995). These indicate a marginal, proximal and distal shelf environment of deposition. The obtained data from calculated palaeoecological factors revealed a gradual sea level rise during the deposition of these rock units, resulting in replacement of the oxic/dysoxic Sarcheshmeh Formation by the dysoxic/anoxic Sanganeh Formation.

In order to explore the possible impact of topography on precipitation between the eastern and western sides of the Liupan Mountains (LMs) in the northwest region of China, the differences in distribution characteristics of total column water vapor (TCWV), total column cloud water (TCCW), and total precipitation (TP) were studied by using the 40-year hourly data of the fifth generation reanalysis (ERA5) from the European Centre for Medium-Range Weather Forecasts (ECMWF). The results showed the following: (1) The TCCW and TP on the eastern and western sides of the LMs decrease gradually from south to north, following a southwestward bias along the latitude. The high values of the TCCW and TP are predominantly concentrated in the period from July to September. The greatest difference between the two sides occurs in September, with the eastern side exhibiting 15% and 18% higher values compared to the western side, respectively. (2) Both the TCCW and TP exhibit distinct diurnal distribution patterns. The high values on the eastern side persist for a longer duration throughout the day compared to the western side, and they occur in more consecutive months. There is a certain correlation between the steepness of the eastern slope and the gentle gradient of the western slope. Additionally, the occurrence of these high values in the afternoon is earlier on the eastern side compared to the western side. (3) The monthly mean TP is significantly linearly correlated with the TCWV and TCCW, with slightly higher coefficients for the western side compared to the eastern side. This relationship is closely related to the topography of the mountain range. The regression equation provides a quantitative tool for predicting the monthly mean TP in the LM region and serves as a reference basis for the development of cloud water resources in the area.

The zooplankton communities of the Gulf of Suez were studied during the period from autumn 2011 to summer 2012. The results showed that, a total of 51 species of holoplankton belonging to 36 genera, distributed among 5 phyla, in addition to 6 groups of meroplankton were collected from the Gulf of Suez. The eastern side was inhabited by 49 species of holoplankton compared to 51 species along the western one. All groups of meroplankton were recorded from both sides. Copepods dominated all other holoplankton species (33 species forming 64.7% of total species number), most of them were cosmopolitan and few species were restricted to at least two neighboring areas. The plankton density averaged 27870 and 21028 organisms/m³ for the eastern and western sides, respectively, with remarkable seasonal variations in species number and density. The highest number of recorded species was 47 and 48, recorded in both eastern and western sides, respectively during spring, associated with a maximum density (40164 and 31586 organisms/m³) during the same season; while the lowest number of species (19 and 23) was recorded during winter at both sides with low density estimated as 9218 and 6493 organisms/m3, for the eastern and western sides, respectively. The present data also showed sharp fluctuations in distribution, characterized by disappearance of several species during winter. Although calanoids dominated all other orders of Copepoda in species number (22 species), but cyclopoids (two species) were plentiful in number of individuals (density). The values of similarities between sites were high, reaching above 0.80 at both sides, and were relatively higher at the northern stations than mid- and southern stations at the eastern side, but the reverse was noted, showing high values of similarity at the southern stations of the western side.

Some characteristics of the Rift Valley in the Atlantic Ocean near 36° 48′ north

Representative ammonites of the Family Heteroceratidae have been studied in this paper. The following forms are recorded from the Koppeh-Dagh Basin: Heteroceras cf. colchicus Djanelidze, Heteroceras spp., Martelites cf. tenuicostatus (Kakabadze), Martelites securiformis (Simonovich, Bastevich and Sorokin), Martelites cf. tinae (Eristavi), Martelites sp.1, Martelites sp. 2, Argvethites sp., Imerites sparcicostatus Rouchadze and Paraimerites sp. A Late Barremian age is suggested for beds containing these forms. The Heteroceras sp. and Martelites securiformis Zones are proposed for the Upper Barremian Sub-Stage in the Koppeh-Dagh Basin. Dispressal paleobiogeographic pattern of Heteroceratidae family and relation between Koppeh-Dagh basin and surrounding basin have been discussed during Late Barremian.

Crustal formation in the Nanling Range, South China Block: Hf isotope evidence of zircons from Phanerozoic granitoids

The Canadian Rockies are a triple-continental divide, whose high mountains are drained by major snow-fed and rain-fed rivers flowing to the Pacific, Atlantic, and Arctic Oceans. The objective of the April–June 2019 Storms and Precipitation Across the continental Divide Experiment (SPADE) was to determine the atmospheric processes producing precipitation on the eastern and western sides of the Canadian Rockies during springtime, a period when upslope events of variable phase dominate precipitation on the eastern slopes. To do so, three observing sites across the divide were instrumented with advanced meteorological sensors. During the 13 observed events, the western side recorded only 25% of the eastern side’s precipitation accumulation, rainfall occurred rather than snowfall, and skies were mainly clear. Moisture sources and amounts varied markedly between events. An atmospheric river landfall in California led to moisture flowing persistently northward and producing the longest duration of precipitation on both sides of the divide. Moisture from the continental interior always produced precipitation on the eastern side but only in specific conditions on the western side. Mainly slow-falling ice crystals, sometimes rimed, formed at higher elevations on the eastern side (>3 km MSL), were lifted, and subsequently drifted westward over the divide during nonconvective storms to produce rain at the surface on the western side. Overall, precipitation generally crossed the divide in the Canadian Rockies during specific spring-storm atmospheric conditions although amounts at the surface varied with elevation, condensate type, and local and large-scale flow fields.

The Triassic Feixianguan Formation's platform‐margin oolitic shoal is a major gas reservoir in the northeastern (NE) Sichuan Basin, along the Kaijiang–Liangping (K–L) Trough. Currently, the platform‐margin oolitic shoal reservoirs in the southern sector of the K–L Trough have been studied relatively little, particularly regarding their characteristics and development. Our detailed studies of petrology and isotope geochemistry have revealed differences in the characteristics of oolitic shoal reservoirs on the eastern and western sides within the southern sector of the K–L Trough. The oolitic shoal reservoirs on the eastern side are mainly composed of intragranular dissolved pores and moldic pores of oolitic dolomite, with high δ 18 O, high Fe and Mn contents, and low 87 Sr/ 86 Sr ratios, with a weak positive correlation between porosity and permeability; pore throats are relatively undeveloped. In contrast, the oolitic reservoirs on the western side are dominated by residual intergranular pores and intergranular dissolved pores of oolitic limestone, with low δ 18 O, low Fe and Mn, and high 87 Sr/ 86 Sr ratios, and their porosity and permeability show a good positive correlation. The throats are thick and the pore throats have a good distribution. The differences of sedimentary paleogeomorphology and diagenetic evolution are considered to be the main causes of the differences of oolitic reservoir characteristics on the eastern and western sides within the southern sector of the K–L Trough. The oolitic shoals on the eastern side formed in a higher and steeper sedimentary topography (slope angles >15°), which promoted vertical stacking because of the steep gradient, and there was greater exposure to meteoric diagenesis. Meteoric diagenesis led to considerable cementation and selective dissolution of the grain fabrics, causing substantial reduction in the original intergranular pores and the development of intragranular dissolved pores and moldic pores. Conversely, the oolitic shoals on the western side formed in a lower and gentler sedimentary topography (slope angles <5°), which migrated laterally toward the trough over large‐scale distances of 9–15 km, and limited exposure to atmospheric diagenesis, which was conducive to the preservation of residual intergranular pores and the further formation of intergranular dissolved pores in the burial process. These results enhance our understanding of the characteristics and development of oolitic reservoirs in the southern sector of the K–L Trough and provide insights for further hydrocarbon exploration of deep oolitic reservoirs.

Physical control of spring–summer phytoplankton dynamics in the North Water, April–July 1998

Wai-San-Ding-Zou is the largest barrier island in the Taiwan area. Due to natural driving forces and active coastal development, this barrier island has been suffering tremendous changes over the years. By using SPOT data taken on September 28, 1986 and July 13, 1993, with 1 cm difference in tidal height, the maximum beach erosion rates across the central section are 193 m/yr and 89 m/yr on the eastern and western sides, respectively. Meanwhile beach accretion has appeared in northern, central and southern parts of the sand-bar. The maximum beach accretion rate in southern part amounts to 257 m/yr. By comparing SPOT data taken on July 13, 1993 and February 6, 1994 with 73 cm difference in tidal height, the slopes of the beach profile across the central part are found to be 0.19/spl deg/ and 0.079/spl deg/ on the western and eastern sides, respectively. The slope at the northern tip is even smaller, about 0.042.

ABSTRACTIn the aseasonal tropical alpine environment, plants experience frequent oscillations of air temperature around zero, but little is known about the leaf temperatures of different plant growth forms in dry versus humid climatic conditions. During July–August 2007, we measured air temperature at 100 cm and 20 cm above the ground, soil temperature at 1 cm and 10 cm depth, and temperatures of leaves and stems of tropical alpine plants on the eastern (windward and cloudy) and western (leeward and sunny) sides of the Antisana volcano (Ecuador) between 4100 m and 4600 m, with the aim of examining the effects of climate and growth forms on leaf temperature. The sunnier climate on the western side of the mountain provided a much broader thermal envelope, in which only leaves of low-statured plants showed significant departure from air temperature during the day. In contrast, most plants had warmer leaves than was the air temperature on the eastern side, and except for cushion plants, the difference in temperature was progressively greater in leaves of taller plants. Plants warmed up significantly faster on the western side and at higher elevations, with the fastest warming rates of 13–15 K h−1 observed in erect herbs. Night cooling rates did not differ between the opposite mountain sides or between elevations. Erect herbs cooled at the fastest rates (3 K h−1), whereas cushion plants cooled at the slowest rates (about 1 K h−1). Height aboveground along with aspect (west vs. east) were the most significant determinants of the leaf thermal microclimate during the day, with elevation having no effect. Low-statured plants experienced more extreme and more variable microclimates than taller plants in sunnier and drier conditions, but the effect of plant height was almost negligible in humid and cloudy climates. In all climatic conditions, cushion plants performed better than any other growth form by achieving higher temperature during the day and preventing rapid cooling during the night.

Effects of contact metamorphism on δ13C, δ15N, and XPS nitrogen functional forms of inertinite-rich Witbank coals (South Africa): Indications for possible alteration by hydrothermal fluids

A 30-yr (1971–2000) study was conducted to 1) determine the typical characteristics and synoptic conditions of foehn wind events that produced large temperature differences near the southern Appalachian Mountains and 2) further examine those events that produced dewpoint rises. Foehn wind events were identified on both the western and eastern sides of the southern Appalachians by comparing temperatures between a station immediately adjacent to the southern Appalachians (foehn station) and two nearby stations located farther from the mountains (nonfoehn station). A foehn wind event occurred when the following criteria were met: the daily maximum or minimum temperature at the foehn station was at least 3°C (∼5°F) higher than the nonfoehn station, winds of at least 2.5 m s−1 (∼5 kt) at the foehn station must have been from a downslope direction, and warming of at least 3°C (∼5°F) must have occurred during the period of downslope winds. Foehn wind events on the western side typically occurred as southeasterly winds developed ahead of a low pressure system over the mid–Mississippi River valley, while foehn wind events on the eastern side were typically the result of northwesterly winds behind the passage of a shallow cold front. The relatively warm 850-hPa air mass, which was only a couple of degrees cooler than the surface temperatures, was likely the source region of the foehn winds on both sides, although additional flow through gaps likely contributed to the less than theoretically possible warming observed at the foehn stations. Composite soundings of the foehn wind events revealed a vertical temperature and wind profile that was conducive to large-amplitude mountain wave formation, especially on the western side of the southern Appalachians. An interesting (and possibly unique) finding observed with these southern Appalachian foehn wind events (compared with other documented foehn wind events) was the rise in surface dewpoints at the foehn stations during nearly three-fourths of the events on the western side and around one-third of the events on the eastern side. A comparison of the dewpoint-rise composites to the composites from all foehn wind events near the southern Appalachians revealed that the rise in surface dewpoints was mainly the result of a drier initial surface air mass (compared with the 850-hPa air mass) and not necessarily a more moist 850-hPa air mass.

SUMMARYThe effects of planting potato tubers on four different sides of two ridge orientations was investigated. Soil temperature was coolest on the northern side, followed by the western, eastern and southern sides. Fifty percent emergence took place in 24, 42 and 49 days for tubers planted on the northern, western and eastern sides, respectively. Only 22% of tubers planted on the southern side emerged. The best yield and quality was obtained by planting on the northern side, followed successively by the eastern, western and southern sides of the ridge.

This study was carried out at El Demokeya Forest Reserve over two seasons (2006\\2007 and 2007\\2008) to determine the effect of tapping direction in relation to sun light on the yield of gum arabic from Acacia senegal. A randomized complete block design experiment with three replications was conducted. The treatments consisted of tapping on the eastern, western, northern and southern sides of the tree. The number of trees per treatment was 10 and 15 in the first and second seasons, respectively. A highly significant difference between tapping direction (P≤ 0.001) was obtained in all pickings except the third picking in the first season and the first picking in the second season. The gum yield increased by 60% when the tapping was on the eastern and western sides towards direct sun light. The combined analysis showed significant differences (P≤ 0.05 and P≤ 0.001) on total gum yield (g/tree) and the number of trees yielding gum. Therefore, tapping of Acacia Senegal tree on the eastern and western sides is recommended.