Dal Group Research Articles

The Impact of the Application of Entrepreneurial Leadership on Competitive Advantage (Applied study on Dal Group)

The purpose of the study was to determine how entrepreneurial leadership contributes to an organization's ability to compete (an applied study on the Dal commercial group). The analytical descriptive technique was used in the investigation. There were 136 male and female responders in the study sample.The study's findings showed that there is a statistically significant relationship between entrepreneurial leadership and the Dal Commercial Group's competitive advantage, as well as a statistically significant impact of entrepreneurial leadership in all of its manifestations (risk, creativity, strategic vision, and initiative).The study produced a number of recommendations, such as:1. The Dal Commercial Group needs to develop the capacity for critical decision-making.2. When dealing with environmental developments, exercise caution to avoid making costly blunders.3. The group should be eager to adopt hidden and fundamental presuppositions that are outside the realm of conventional wisdom.

The Permian to Cretaceous succession at Permpasset, Wollaston Forland: the northernmost Permian and Triassic in North–East Greenland

Permian to Triassic outcrops in East Greenland diminish significantly northwards. Understanding the northward extent, and nature, of the Permian and Triassic successions has implications for regional palaeogeographic reconstructions and exploration in adjacent offshore basins. Examining the structural relationships between the basement, Permian, Triassic, Jurassic and Cretaceous successions can further our understanding of the tectonic evolution of the region. Here, we describe a hitherto overlooked section through the Permian to Cretaceous from central Wollaston Forland and consider its structural context. The western side of Permpasset forms the upthrown eroded crest of a horst block, which provides exposure of the earliest stratigraphic intervals in the region. The fractured Caledonian basement is overlain by evaporitic marine limestone facies of the Karstryggen Formation, which are succeeded by shallow marine sandstones assigned to the Schuchert Dal Formation, both Upper Permian. The overlying unit records a period of fluvial deposition and is not possible to date. However, an Early to Middle Triassic age (Pingo Dal Group) seems most likely, given regional eustatic considerations. This is, therefore, the most northerly record of Triassic strata in North–East Greenland. West of the horst structure, fine-grained sandstones and bioturbated siltstones of the Jurassic (Oxfordian) Jakobsstigen Formation are recorded. These were downfaulted prior to a prolonged hiatus after which both the Triassic and Jurassic strata were draped by Cretaceous shales of the Fosdalen Formation. The Cretaceous succession is overlain by a thick basalt pile of Eocene age, heralding the opening of the North-East Atlantic. Glendonites overlie Oxfordian siltstones at the base of the middle Albian Fosdalen Formation. These were likely winnowed from slightly older Cretaceous strata and overlie the hiatus surface between the Jurassic and Cretaceous. This is the first record of glendonites from the Cretaceous of East Greenland and they are interpreted to record the Circum–Arctic late Aptian – early Albian cooling event.

Sensory Evaluation of Camel Milk Set Type Yoghurt as Affected by Addition of Starch, Skim Milk and Storage Periods

The present study was conducted in the laboratory of Dal Group for food, department of quality and new product development (NPD), Khartoum, Sudan, to assess the sensory properties of camel milk set type yoghurt fortified with 4% milk protein, 1% gum Arabic in order to assess the effect of addition of skim milk powder and modified starch either individually or combined at different levels on the sensory quality of yoghurt, and to compare these properties of camel milk yoghurt processed with addition of stabilizer to that processed without stabilizer. The effect of storage period on the sensory quality of camel milk set type yoghurt was also investigated. Nine panelists were chosen to judge on the quality of camel milk set type yoghurt in terms of appearance, body texture, mouth feel, taste, aroma and overall acceptability. The sensory evaluation was evaluated by scoring procedure. The panelists were given a hedonic questionnaire to test the mentioned sensory characteristics when fresh and after 7, 15, 21 and 30 days of storage periods. The findings indicated that the sensory evaluation of camel milk set type yoghurt treatments were appeared significant (p≤0.05) in some yoghurt samples. According to the results, the relationship between the sensory attributes and the fortification type/ratio was found to be had significant (p> 0.05) roles in some yoghurt samples. The sensory evaluation tests indicated that the camel milk set type -yoghurts fortified with 3% SMP had significantly (p≤0.05) higher scores in appearance, mouth feel, texture, taste and flavor. However, the product supplemented with 3% SMP showed better overall acceptability scores compared to other treatments. In concluded remarks panelists gave the highest scores for flavor, texture, appearance and overall acceptability to the yoghurt fortified with skim milk than the control and other yoghurt samples, more research is needed to evaluate the microbial and quality aspects of camel milk set type yoghurt as recommended point of view for future work.

Middle–Late Triassic evolution of the Jameson Land Basin, East Greenland

AbstractThe Jameson Land Basin lies within the Greenland–Norway rift, to the south of Triassic basins on the Halten Bank and East Greenland shelf, and can therefore offer insights into the development of these less-well-documented offshore basins and the wider North Atlantic. This study focuses on the stratigraphic development of the Jameson Land Basin. Broad-scale stratigraphic logging is augmented with heavy mineral analysis that constrains the dominant source catchments during this period. A thickness of over 1.5 km of Middle–Late Triassic strata fill the Jameson Land Basin, predominantly comprising continental deposits laid down during arid to semi-arid climatic conditions. The basal Pingo Dal Group thickens westwards into the Stauning Alper Fault, forming a typical syn-rift succession. Thickness variations have also highlighted the presence of an intrabasinal high and an associated unconformity between the Pingo Dal Group and the overlying Gipsdalen Group, which provides the first direct evidence for Middle–Late Triassic rifting in East Greenland. Thickness variations in the overlying Gipsdalen Group are more subdued, and the Fleming Fjord Group, and its formations, display remarkably tabular geometries, with little evidence for significant lateral facies variance; this is suggestive of reduced topography and a more regional thermal subsidence signature. Provenance data indicate sediment sourcing from both the western and eastern basin margins during the deposition of the Pingo Dal Group, above which the western source area becomes dominant, alongside some axial input from the south.

Triassic lithostratigraphy of the Jameson Land Basin (central East Greenland), with emphasis on the new Fleming Fjord Group

The lithostratigraphy of the Triassic deposits of the Jameson Land Basin in central East Greenland is revised. The new Scoresby Land Supergroup is now composed of the Wordie Creek, Pingo Dal, Gipsdalen and Fleming Fjord Groups. This paper only deals with the lithostratigraphy of the late Early-Late Triassic continental deposits of the latter three groups with emphasis on the vertebratebearing Fleming Fjord Group. The new Pingo Dal Group consists of three new formations, the Rødstaken, Paradigmabjerg and Klitdal Formations (all elevated from members), the new Gipsdalen Group consists of three new formations, the Kolledalen, Solfaldsdal (with the new Gråklint Member) and Kap Seaforth Formations (all elevated from members), and the new Fleming Fjord Group is subdivided into three new formations, the Edderfugledal, Malmros Klint and Ørsted Dal Formations (all elevated from members). The Edderfugledal Formation contains two cyclic bedded, lacustrine members, a lowermost Sporfjeld Member (elevated from beds), and an uppermost Pingel Dal Member (elevated from beds). The lacustrine red beds of the Malmros Klint Formation are not subdivided. The lacustrine and fluvial Ørsted Dal Formation contains three new members. In the eastern and central part of the basin, the formation is initiated by cyclic bedded, red lacustrine mudstones of the Carlsberg Fjord Member (elevated from beds), while in the northwestern part of the basin the lowermost part of the formation is composed of grey fluvial conglomerates and sandstones with subordinate red mudstones of the Bjergkronerne Member (elevated from beds). The uppermost part of the formations in most of the basin is composed of cyclic bedded, variegated lacustrine mudstones and grey to yellowish marlstones of the Tait Bjerg Member (elevated from beds). The sediments in the Fleming Fjord Group contain remains of a rich and diverse vertebrate fauna including dinosaurs, amphibians, turtles, aeotosaurs, pterosaurs, phytosaurs and mammaliaforms. Most vertebrate bones have been found in uppermost Malmros Klint Formation, and in the Carlsberg Fjord and Tait Bjerg Members. The Norian–early Rhaetian, lacustrine Fleming Fjord Group was deposited at about 41° N on the northern part of the supercontinent Pangaea. Lacustrine sedimentation was controlled by seasonal as well as longer-term (orbital) variation in precipitation. Precipitation was probably brought to the basin by southwesterly winds. The lacustrine sediments of the uppermost Fleming Fjord Group show deposition during increasingly humid conditions changing the lake environment from an ephemeral lake-steppe area to a perennial lake. This evolution of lake environment suggests a change from a winter-wet temperate climate to one with precipitation throughout the year.

Triassic lithostratigraphy of the Jameson Land Basin (central East Greenland), with emphasis on the new Fleming Fjord Group

The lithostratigraphy of the Triassic deposits of the Jameson Land Basin in central East Greenland is revised. The new Scoresby Land Supergroup is now composed of the Wordie Creek, Pingo Dal, Gipsdalen and Fleming Fjord Groups. This paper only deals with the lithostratigraphy of the late Early-Late Triassic continental deposits of the latter three groups with emphasis on the vertebratebearing Fleming Fjord Group. The new Pingo Dal Group consists of three new formations, the Rødstaken, Paradigmabjerg and Klitdal Formations (all elevated from members), the new Gipsdalen Group consists of three new formations, the Kolledalen, Solfaldsdal (with the new Gråklint Member) and Kap Seaforth Formations (all elevated from members), and the new Fleming Fjord Group is subdivided into three new formations, the Edderfugledal, Malmros Klint and Ørsted Dal Formations (all elevated from members). The Edderfugledal Formation contains two cyclic bedded, lacustrine members, a lowermost Sporfjeld Member (elevated from beds), and an uppermost Pingel Dal Member (elevated from beds). The lacustrine red beds of the Malmros Klint Formation are not subdivided. The lacustrine and fluvial Ørsted Dal Formation contains three new members. In the eastern and central part of the basin, the formation is initiated by cyclic bedded, red lacustrine mudstones of the Carlsberg Fjord Member (elevated from beds), while in the northwestern part of the basin the lowermost part of the formation is composed of grey fluvial conglomerates and sandstones with subordinate red mudstones of the Bjergkronerne Member (elevated from beds). The uppermost part of the formations in most of the basin is composed of cyclic bedded, variegated lacustrine mudstones and grey to yellowish marlstones of the Tait Bjerg Member (elevated from beds). The sediments in the Fleming Fjord Group contain remains of a rich and diverse vertebrate fauna including dinosaurs, amphibians, turtles, aeotosaurs, pterosaurs, phytosaurs and mammaliaforms. Most vertebrate bones have been found in uppermost Malmros Klint Formation, and in the Carlsberg Fjord and Tait Bjerg Members. The Norian–early Rhaetian, lacustrine Fleming Fjord Group was deposited at about 41° N on the northern part of the supercontinent Pangaea. Lacustrine sedimentation was controlled by seasonal as well as longer-term (orbital) variation in precipitation. Precipitation was probably brought to the basin by southwesterly winds. The lacustrine sediments of the uppermost Fleming Fjord Group show deposition during increasingly humid conditions changing the lake environment from an ephemeral lake-steppe area to a perennial lake. This evolution of lake environment suggests a change from a winter-wet temperate climate to one with precipitation throughout the year.

Prevalence of Dal blood type and dog erythrocyte antigens (DEA) 1, 4, and 7 in canine blood donors in Italy and Spain

BackgroundThe aim of this study was to determine the prevalence of Dal, and DEA 1, 4, 7 blood types, in a population of canine blood donors from Italy and Spain. Three hundred and twenty blood donor dogs receiving an annual health evaluation were included in the study. DEA 1 blood type was determined using an immunochromatographic strip technique while Dal, DEA 4 and 7 blood types were determined with polyclonal antisera using agglutination on gel columns.ResultsOut of 320 dogs blood typed 7 (2 Cane Corso and 5 Doberman Pinschers) (2.2%) were Dal negative; 137 (42.8%) were positive for DEA 1; 320 (100%) were positive for DEA 4 and 43 (13.4%) were positive for DEA 7.ConclusionThis study showed a similar prevalence of DEA 1, 7 and 4 to that reported in previous studies in the same, and in different, geographic areas, and provides new data on the prevalence of the Dal blood group in Italy and Spain. There was no significant difference (P = 0.8409) between prevalence of Dal negative blood types found in our population (2.2%) and the prevalence reported in a canine blood donor population from the USA (2.5%). Our study identified Dal negative dogs in a previously tested breed i.e. Doberman Pinschers, but also the Cane Corso breed was found to have Dal negative dogs.

New U-Pb constraints on the age of the Little Dal Basalts and Gunbarrel-related volcanism in Rodinia

Diabase exposed amongst outcrops of the Little Dal Basalts (LDB) between the Coates Lake Group and overlying the Little Dal Group in the Mackenzie Mountains of northern Canada has a geochemical signature that is characteristic of the LDB and associated Tsezotene sills. Marginally concordant magmatic zircons from a sample of the diabase yielded CA-ID-TIMS weighted mean 207Pb/206Pb and 206Pb/238U dates of 778.4±1.8Ma (2σ) and 775.10±0.54Ma (2σ), respectively. These dates provide the first direct constraint on the age of the LDB and confirm a temporal relationship to the widespread Gunbarrel magmatic event that affected western North America during the protracted breakup of the supercontinent Rodinia. Hafnium isotopes were measured on three grains and calculated values of εHf at 775Ma are 9.5±0.4, 9.7±0.2 and 9.3±0.2 (2σ), consistent with a mantle plume genesis.Gunbarrel magmatism was not temporally related to the final fragmentation of Rodinia and the establishment of the west Laurentian continental margin (rift-drift transition), which did not occur until after 720Ma. However, the age and stratigraphic position of the LDB suggest the Gunbarrel event may have thermally weakened the lithosphere leading to a period of intracontinental rifting and the deposition of the Coates Lake Group rift-sediments prior to 732Ma.The sample of diabase also yielded a single 207Pb/206Pb 1565.7±1.5Ma xenocrystic zircon with a model Th/U ratio of 0.47 indicative of a crustal origin. Although there is limited evidence for felsic magmatism, metamorphism, and orogenesis of this age in western Laurentia, a range of felsic volcanic rocks and/or intrusive suites of this age do occur in southern, central and eastern Australia, supporting existing reconstructions of the Nuna/Columbia supercontinent that place the northwest margin of Laurentia adjacent to Australia.

Thick sulfate evaporite accumulations marking a mid-Neoproterozoic oxygenation event (Ten Stone Formation, Northwest Territories, Canada)

Thick sulfate evaporite accumulations are absent from Proterozoic strata between ca. 2000 and ca. 1000 Ma, and detailed sedimentologic, stratigraphic, and geochemical data for the oldest Neoproterozoic thick marine sulfate evaporite successions are largely lacking. The middle Neoproterozoic Ten Stone Formation (Little Dal Group, Northwest Territories, Canada) consists of ~500 m of pelagic lagoonal gypsite and anhydritite (rocks consisting of the minerals gypsum and anhydrite) deposited shortly before the ca. 811 Ma Bitter Springs carbon isotope anomaly in an intracratonic basin that developed prior to breakup of Rodinia. The thickness of regional stratigraphic subdivisions of this formation, defined by subtle silt- and carbonate-bearing intervals, indicates a minor terrigenous source in the southeast and a silled connection to the open ocean in the northwest. Deposition of the Ten Stone Formation began with abrupt, tectonically triggered subsidence and restriction, and ended equally abruptly, as shown by stratigraphic contacts across which lithofacies corresponding to strikingly different paleoenvironments change sharply, with no evidence for hiatus or erosion. Stratigraphic cyclicity in the evaporite succession is minimal owing to isolation of bottom-hugging, dense lagoonal brine from overlying waters. Deposition of the Ten Stone Formation in a basin that experienced intermittent, basin-scale tectonic adjustments, as recorded by details of its stratigraphy, supports the interpretation that the Mackenzie Mountains Supergroup accumulated in an extensional, tectonically active intracratonic basin whose structure resembled a lower-plate extensional system. The absence of halite from the Ten Stone Formation contrasts with its abundance in the stratigraphically lower, gypsum-free Dodo Creek Formation, suggesting that deposition of the lower to middle Little Dal Group spanned a major oxygenation event, during which the sequence of evaporite mineral precipitation from seawater changed from halite-first to sulfate-first in response to rapid accumulation of atmospheric oxygen and concomitant increase in the global marine sulfate reservoir. The limited range of sulfur isotope values in a new data set spanning hundreds of meters of gypsite indicates a strongly and persistently oxidizing mid-Neoproterozoic atmosphere, an abundance of sulfate in seawater, and marine oxygenation extending below storm wave base. The mineralogy, sedimentology, stratigraphy, and geochemistry of the Ten Stone Formation are virtually indistinguishable from those of thick, Phanerozoic “deep-water” (below wave-base) evaporite successions, and indicate that the tectonic, climatic, and geochemical conditions required for deposition of thick successions of marine sulfate evaporites were well established prior to ca. 811 Ma. Thick sulfate evaporite successions in equivalent stratigraphic positions just below the Bitter Springs carbon isotope excursion elsewhere in Laurentia, as well as on the Congo craton, and in South Australia attest to the global impact of the rapidly increased seawater sulfate reservoir prior to Rodinia’s breakup. High relative burial rates of organic matter prevailed before the breakup of Rodinia and led to oxygenation of the atmosphere-ocean system, growth of the seawater sulfate reservoir, and, in association with a warm and arid climate, deposition for the first time in Earth’s history of thick sulfate evaporites in the middle Neoproterozoic, ~100 m.y. before the first Cryogenian glacial episode. The Neoproterozoic Oxygenation Event may have taken place in several steps, the first of which preceded the Bitter Springs anomaly.

Sequence and tectonostratigraphy of the Neoproterozoic (Tonian-Cryogenian) Amundsen Basin prior to supercontinent (Rodinia) breakup

Intracontinental basins that lack obvious compartmentalization and extensional faults may lie inboard of, and have the same timing as, rifted continental margins. Neoproterozoic successions of northwest Laurentia are an example where rift and intracontinental basins are spatially and temporally related. This study describes Tonian-Cryogenian pre-rift strata of the upper Shaler Supergroup, deposited in the Amundsen Basin (Victoria Island, Canada), in which five transgressive-regressive (T-R) cycles are identified. The pre-breakup succession in the Amundsen Basin has stratigraphic architecture that differs from adjacent, fault-bound rift basins. There is little evidence for extensive progradation, which resulted in broad, layer-cake stratigraphy where shallow-water facies predominate, deposited on a storm-dominated ramp. Correlation between the Amundsen and Fifteenmile (Yukon) basins is complicated by differing rates and regimes of subsidence, with the exception of a basin-deepening event that occurred in both basins and correlates with the global Bitter Springs isotope stage, initiating sometime after ∼811Ma. Contrary to previous correlations, we propose that the upper Shaler Supergroup and Little Dal Group of the Mackenzie Mountains Supergroup (Mackenzie Basin) are equivalent to the entire Fifteenmile Group. The identification of cycles and subsidence patterns in the Amundsen Basin prior to Rodinia break-up has implications for understanding the stratigraphic architecture of other intracontinental sag basins. We recognize three tectonostratigraphic units for the upper Shaler Supergroup that record an initial sag basin, followed by early extension and thermal doming, and finally rifting of the Amundsen Basin. Subsidence possibly was related to multiple cycles of intra-plate extension that complemented coeval fault-controlled subsidence. Analysis of pre-rift strata in the Amundsen Basin supports multi-phase, non-correlative break-up of Rodinia along the northwest margin of Laurentia.

Drinking to thirst versus drinking ad libitum during road cycling.

The sensation of thirst is different from the complex behavior of drinking ad libitum. Rehydration recommendations to athletes differ, depending on the source, yet no previous researchers have systematically compared drinking to thirst (D(TT)) versus ad libitum drinking behavior (D(AL)). To compare 2 groups of trained cyclists (D(TT) and D(AL)) who had similar physical characteristics and training programs (P > .05). The D(TT) group (n = 12, age = 47 ± 7 years) drank only when thirsty, whereas the D(AL) group (n = 12, age = 44 ± 7 years) consumed fluid ad libitum (ie, whenever and in whatever volume desired). Cohort study. Road cycling (164 km) in the heat (36.1 °C ± 6.5 °C). Ultraendurance cyclists (4 women, 20 men). We recorded measurements 1 day before the event, on event day before the start, at 3 roadside aid stations, at the finish line, and 1 day after the event. Body mass, urinary hydration indices, and food and fluids consumed. No between-groups differences were seen on event day for total exercise time (DTT = 6.69 ± 0.89 hours, DAL = 6.66 ± 0.77 hours), urinary indices (specific gravity, color), body mass change (D(TT) = -2.22% ± 1.73%, DAL = -2.29% ± 1.62%), fluid intake (D(TT) = 5.63 ± 2.59 L/6.7 h, D(AL) = 6.04 ± 2.37 L/6.7 h), dietary energy intake, macronutrient intake, ratings of thirst (D(TT) start = 2 ± 1, D(TT) finish = 6 ± 1, DAL start = 2 ± 1, D(AL) finish = 6 ± 1), pain, perceived exertion, or thermal sensation. Total fluid intake on recovery day +1 was the primary significant difference (D(AL) = 5.13 ± 1.87 L/24 h, D(TT) = 3.13 ± 1.53 L/24 h, t18 = 2.59, P = .02). Observations on event day indicated that drinking to thirst and drinking ad libitum resulted in similar physiologic and perceptual outcomes. This suggests that specific instructions to "drink to thirst" were unnecessary. Indeed, if athletes drink ad libitum, they can focus on training and competition rather than being distracted by ongoing evaluation of thirst sensations.

‘We do our bit in our own space’: DAL Group and the development of a curiously Sudanese enclave economy

ABSTRACTThe family firm, DAL Group, is Sudan's largest and most diversified company. Its growth has concentrated on consumer goods, rather than on state concessions or exports. It has developed its own training programmes, construction units, transportation networks and market research departments to manage the unstable environment outside its business walls. This paper focuses on the company's recruitment policies, demonstrating how the firm relies on its own internal family structure and a transnational network of Sudanese professionals in order to grow and prosper. Such self-reliance contributes to growing political frustration among young unemployed people. Graduates from ‘marginal’ areas rely more heavily on public advertisements and on information obtained from state bodies, not the private channels of wasta (personal intermediation) that cut through contemporary business. The paper concludes by comparing DAL with similar business networks in Ethiopia and Rwanda, arguing that DAL is a unique and interesting form of ‘enclave economy’, shaped by a displaced transnational elite operating in a hostile political environment. Within the wider political context of Sudan, there is a limit to what similar businesses can achieve.

Effects of Aerobic Exercise Training in Anemic Cancer Patients Receiving Darbepoetin Alfa: A Randomized Controlled Trial

Anemia in patients with solid tumors is a common problem that is associated with impaired exercise capacity, increased fatigue, and lower quality of life (QoL). Erythropoiesis-stimulating agents (ESAs) have been shown to improve these outcomes; however, it is unknown if additional benefits can be achieved with aerobic exercise training. We conducted a single-center, prospective, randomized, controlled trial in 55 mild-to-moderately anemic patients with solid tumors. Patients were randomized to either darbepoetin alfa alone (DAL, n = 29) or darbepoetin alfa plus aerobic exercise training (DEX; n = 26). The DEX group performed aerobic exercise training three times per week at 60%-100% of baseline exercise capacity for 12 weeks. The primary endpoint was QoL assessed by the Functional Assessment of Cancer Therapy-Anemia scale. Secondary endpoints were fatigue, cardiorespiratory fitness (VO(2peak)), hemoglobin (Hb) response, and darbepoetin alfa dosing. Intention-to-treat analyses indicated significant improvements in QoL and fatigue in both groups over time but there were no between-group differences. The DEX group had a significantly greater VO(2peak) than the DAL group (mean group difference, +3.0 ml/kg per minute; 95% confidence interval, 1.2-4.7; p = .001) and there were borderline significant differences in favor of the DEX group for Hb response and darbepoetin alfa dosing. Aerobic exercise training did not improve QoL or fatigue beyond the established benefits of DAL but it did result in favorable improvements in exercise capacity and a more rapid Hb response with lower dosing requirements. Our results may be useful to clinicians despite the more recent restrictions on the indications for ESAs.

Discoveries of new Longfengshaniaceae from the uppermost Ediacaran in eastern Yunnan, South China and the significance

A morphologically more diverse assemblage of Longfengshaniaceae has been found in the uppermost Ediacaran (Sinian) Jiucheng Member, Yuhucun Formation at Jinning and Jiangchuan, eastern Yunnan, South China. A majority of them are different from the Longfengshania found in the Neoproterozoic Changlongshan Formation, Yanshan Mountain area, North China and the Little Dal Group, North America. They are mainly characterized by a more varied, often thallus-like appearance with no branches, such as oval, pyriform, spindle, shovel, heart, ribbon and balloon shapes, and more sturdy stalk-like projection (stipe) with a smooth connection on the basal part of the thallus. In addition, they appear to have a remarkable attaching organ of lanceolate, shuttle-like or short stem-like structure at the base of the stipe. Six distinct morphological taxa are recognized, including one new genus, two new species and three conformis species. The characteristics of the family and the genus Longfengshania are further discussed in this paper. The new discoveries of these carbonaceous macrofossils identified as Longfengshaniaceae algae on the basis of the diagnostic forms and anastomosis patterns of their thalli and stipes demonstrate that an important evolutionary radiation of metaphytes took place in the last Ediacaran stage. The flourishing of the benthonic thallophytes attached to the substrate from eastern Yunnan and considered to be photosynthetic alga probably provided continuous nutritional habitats for the explosion and diversification of the Early Cambrian “Chengjiang biota”.

Mesoproterozoic bimodal volcanism in SW Norway, evidence for recurring pre-Sveconorwegian continental margin tectonism

Between ca. 1.3 Ga and the onset of the Sveconorwegian orogeny (ca. 1.0 Ga) in the Baltic Shield, the margin of Baltica was subjected to repeated episodes of bimodal magmatism. A new TIMS U–Pb date of 1259 +/− 2 Ma for magmatic zircon from metarhyolite of the Trossovdal Formation is presented. At least two distinct episodes of bimodal volcanism in southern Norway: the 1.26 Ga Valldal Group and 1.16 Ga Oftefjell and Høydalsmo groups are now recognized. The Dal Group in south-western Sweden is a more distal equivalent of the latter. In the Valldal region, volcanism developed in an extensional setting, following the initial deposition of clastic sediments. The earliest volcanics are A-type peraluminous rhyolites, with Nd and Hf isotopic compositions supporting formation by remelting of 1.5–1.9 Ga granitic basement, initiated by the intrusion of mafic magmas. Subsequent volcanism comprised subaerial basaltic lava flows, locally intercalated with clastic sediments. The earliest basaltic magmas (Hagastøl Formation) are chemically the more evolved and contain the lavas that suffered crustal contamination, whereas, the later basalts (Austmannali Formation) are consistent with melting of a depleted mantle source. However, all of the basalts have elevated La/Nb values relative to MORB. This feature is consistent with asthenospheric melts variably contaminated by a lithospheric mantle component, which had been previously enriched by an earlier subduction event. The combination of early clastic sedimentation, bimodal volcanism and igneous geochemistry suggests that the Valldal volcanics formed in a continental back-arc setting. The new data suggest that at least from ca. 1.3 Ga the proto-margin of Baltica was possibly a convergent continental margin, with back-arc development occurring diachronously along its length from ca. 1.26 to 1.16 Ga. Magmas produced during these two volcanic episodes have distinct geochemical and isotopic signatures and their geographic distribution suggests that each is restricted to a discrete crustal terrain. This further supports the view that during the Sveconorwegian orogeny large-scale strike slip tectonics juxtaposed the different terranes to give the present crustal geometry.

Paleoenvironments and growth of early Neoproterozoic calcimicrobial reefs: platformal Little Dal Group, northwestern Canada

Although the calcimicrobial reefs of the basinal Little Dal Group (<1080 Ma; >780 Ma) are well-described, little is known about related shallow-water facies to the southeast. Study of these platformal carbonates shows that they represent inner, mid- and shallow outer ramp zones of a homoclinal, storm-influenced ramp. Seven depositional sequences are recognized and correlated with reef-bearing strata in the Little Dal basin and in the Shaler Supergroup of Victoria Island. Reef distribution is distinctly depth partitioned across the Little Dal ramp. Inner and mid-ramp carbonates contain meter-scale mounds, patch reefs, and biostromes composed of fine-grained stromatolites including Tungussia, Baicalia, and Jurusania. These reefs are strikingly similar to those reported from coeval shallow-water strata in the Shaler Supergroup of Victoria Island and the Bitter Springs Formation of Australia. Multi-storey stromatolitic biostrome/bioherm complexes greater than 100 m in height, seem to be restricted to the mid-ramp zone of the Little Dal ramp and probably reflect high rates of subsidence in the Mackenzie Basin. Calcimicrobial reefs occur only in the deepest water strata of the study area, associated with outer ramp sediments. These reefs contain calcified cyanobacterial filaments in varying degrees of preservation, and are petrographically indistinguishable from the kilometre scale basinal calcimicrobial reefs to the northwest. The association of calcimicrobial reefs with deep, low-energy environments suggests initial establishment of reef-building calcimicrobes in deep-water benthic environments.

Geochemistry of late Mesoproterozoic volcanism in southwestern Scandinavia: implications for Sveconorwegian/Grenvillian plate tectonic models

Abstract: The last magmatic stage before the Sveconorwegian orogeny in the Baltic Shield is represented by bimodal, c. 1.16 Ga volcanics from the Bandak Group in southern Norway and largely coeval basalts from the Dal Group in SW Sweden. In both areas, the volcanic rocks are intercalated with sedimentary units and the onset of basin development is marked by deposition of clastic sediments. In the lower part of the Bandak Group, the Morgedal basalts are relatively evolved and geochemical signatures suggest assimilation of lower crustal components. In contrast, the subsequent Gjuve basalts are more primitive and record assimilation of upper crustal rocks similar to exposed basement rocks. In the Bandak Group, the chemistry of the basalts changes within the stratigraphy, such that the older Morgedal basalts (MgO = 5.2–8.8 wt%, initial ϵ Nd 2.81–3.96, Zr/Y = 4.0–5.1, Zr/Nb = 34–50, La/Nb = 2.4–3.7) are more fractionated and have more enriched Nd isotope ratios compared to the Gjuve basalts (MgO = 6.4–12.3 wt%, initial ϵ Nd 4.05–4.97, Zr/Y = 3.4–4.7, Zr/Nb = 20–30, La/Nb = 1.5–2.4). This suggests that there earliest basalts are more contaminated, and it appears that the composition of the crustal component changed with time. A thin felsic volcanic unit, the Dalen Formation, separates the two basalt sequences. It represents melting of upper crustal rocks, triggered by injection of mafic magmas into crustal magma chambers. In the Dal Group, basalts form a relatively thin unit (&lt; 500 m) where flows with high MgO values (&gt; 9%) were least affected by assimilation of crustal components. Whole-rock geochemistry and Nd isotope ratios for the Bandak and Dal basalts indicate shallow melting of sub-continental lithospheric mantle in response to extension in a continental back-arc setting, related to subduction along the western margin of Baltica. These constraints envision a similar tectonic evolution with that of eastern Laurentia, which support models of a pre-Grenvillian supercontinent with a long-lived, active margin that reached western Baltica.

Taphonomic Control on Microstructure in Early Neoproterozoic Reefal Stromatolites and Thrombolites

Other| April 01, 2000 Taphonomic Control on Microstructure in Early Neoproterozoic Reefal Stromatolites and Thrombolites ELIZABETH C. TURNER; ELIZABETH C. TURNER 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar NOËL P. JAMES; NOËL P. JAMES 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar GUY M. NARBONNE GUY M. NARBONNE 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information ELIZABETH C. TURNER 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada NOËL P. JAMES 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada GUY M. NARBONNE 1Department of Geological Sciences, Queen's University, Kingston, Ontario, K7L 3N6, Canada Publisher: SEPM Society for Sedimentary Geology Accepted: 08 Dec 1999 First Online: 03 Mar 2017 Online ISSN: 1938-5323 Print ISSN: 0883-1351 Society for Sedimentary Geology PALAIOS (2000) 15 (2): 87–111. https://doi.org/10.1669/0883-1351(2000)015<0087:TCOMIE>2.0.CO;2 Article history Accepted: 08 Dec 1999 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ELIZABETH C. TURNER, NOËL P. JAMES, GUY M. NARBONNE; Taphonomic Control on Microstructure in Early Neoproterozoic Reefal Stromatolites and Thrombolites. PALAIOS 2000;; 15 (2): 87–111. doi: https://doi.org/10.1669/0883-1351(2000)015<0087:TCOMIE>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyPALAIOS Search Advanced Search Abstract Early Neoproterozoic reefs of the Little Dal Group, Northwest Territories, are built by stromatolites and thrombolites containing calcified filamentous cyanobacteria and interstitial cement. Micritic and microcrystalline carbonate grew in or on extracellular cyanobacterial sheaths, preserving filaments when mineralization was early relative to sheath degradation, or grumeaux when mineralization was later. Filamentous microstructure is volumetrically predominant in the reefs; less common are micritic and grumelous microstructures already known from late Proterozoic stromatolites and Phanerozoic thrombolites. Textural intergradation of filamentous-calcimicrobial microstructure with these non-filamentous microstructures reflects microstructural variation developed through differential preservation at the scale of individual filaments and laminae. Textural gradients from filaments to grumeaux, and from calcimicrobial to stromatolitic and thrombolitic microstructure types, imply that a wide variety of microbialite microstructure types can be derived from a single progenitor community. This suggests that taphonomic variables may be as important in the development of microbialite microstructure as the biology of the microbial mat community. It also challenges recent suggestions that the Neoproterozoic increase in thromboids was related to the rise of multicellular organisms. These conclusions have broad implications for the interpretation of fossil microbialites, many of which might have been more closely related in origin than hitherto suspected. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Taphonomic Control on Microstructure in Early Neoproterozoic Reefal Stromatolites and Thrombolites

Abstract Early Neoproterozoic reefs of the Little Dal Group, Northwest Territories, are built by stromatolites and thrombolites containing calcified filamentous cyanobacteria and interstitial cement. Micritic and microcrystalline carbonate grew in or on extracellular cyanobacterial sheaths, preserving filaments when mineralization was early relative to sheath degradation, or grumeaux when mineralization was later. Filamentous microstructure is volumetrically predominant in the reefs; less common are micritic and grumelous microstructures already known from late Proterozoic stromatolites and Phanerozoic thrombolites. Textural intergradation of filamentous-calcimicrobial microstructure with these non-filamentous microstructures reflects microstructural variation developed through differential preservation at the scale of individual filaments and laminae. Textural gradients from filaments to grumeaux, and from calcimicrobial to stromatolitic and thrombolitic microstructure types, imply that a wide variety of...

Growth Dynamics of Neoproterozoic Calcimicrobial Reefs, Mackenzie Mountains, Northwest Canada

ABSTRACT Neoproterozoic buildups of the Little Dal Group grew in a deep-water epicratonic basin. These kilometer-scale reefs display aggradational and progradational geometries comparable to those described from Phanerozoic reefs. Four phases of reef growth correspond to four regional shale-to-carbonate packages in laterally equivalent off-reef strata. The lower, shaly part of each package is interpreted to reflect transgressive to highstand deposition. The upper carbonate part of each package reflects carbonate precipitation in the water column as a result of postulated basin restriction and increased salinity during sea-level lowstand. Reefs nucleated at the beginning of the first major transgressive event. Reefs typically aggraded during transgressive intervals, but could also prograde or contract, likely depending on the rate of relative sea-level rise versus reef growth rate. Reefs prograded during regressions, probably owing to reduction of accommodation space. They shed talus at lowstand in response to increased erosion and/or progradation over unstable substrates. Reef growth ended with return of shallow-water conditions. The overall architecture of aggradation and progradation demonstrates that the Neoproterozoic calcimicrobial reef ecosystem was capable of responding to environmental changes in the same way as the more extensively studied, ecologically complex, and faunally diverse buildups of the Phanerozoi .