Lateral Fan Research Articles

COMPARATIVE CHARACTERISTICS OF THE LINEAR DIMENSIONS OF VARIOUS FORMS OF THE FACIAL SKULL

For many years, radiography has traditionally been the main method for studying of the morphology of the facial skull and identifying craniofacial deformities, however, it is difficult to assess the typical variability of the linear dimensions of the facial skull on radiographs due to the many overlapping shadows of anatomical structures. Comparison of the results of craniometry of macerated skulls, radiographs and spiral computed tomography shows that multislice computed tomography in some cases can be the best alternative to conventional radiography and other methods of studying the facial skull. The purpose of the study was to conduct a comparative analysis of the linear dimensions of the facial skull with its various forms according to multislice computed tomography. Tomograms of 105 patients with different facial skull shapes were studied. Tomography was performed on a «Brilliance 64 Slice» multislice spiral X-ray computed tomography scanner at the Department of Magnetic Resonance and X-ray Computed Tomography of the Rostov State Medical University for suspected cerebrovascular pathology. The obtained images were analyzed using axial, multiplanar, and shadow density surface reconstructions in various projections. Measurements were made using a standard digital ruler of a computer tomography workstation, typical features of the linear dimensions of the facial skull were evaluated using the fan-beam method. In the studied group of individuals, the predominance of euryenes (46.7%, n=49) over mezenes (37.2%, n=35) and leptens (18.1%, n=9) was revealed. A comparative characteristic of the linear dimensions of the facial skull on spiral computed tomograms is described. According to the results of the study, the linear dimensions of the facial skull on the right dominate in leptens and euryenes, on the right in sections of the upper fan on the right, and on the left in sections of the lower and lateral fans. A left-sided asymmetry of the linear dimensions of the facial skull in sections of the lower fan, which is characteristic of mezenes, was established, while a right-sided asymmetry was found for euryenes and leptens. The data obtained as indicators of normal craniometry can be used in clinical practice by radiologists, plastic surgeons, maxillofacial surgeons, as well as in anthropology and forensic medicine.

SEX-RELATED FEATURES OF THE ASYMMETRY OF CRANIOMETRICS PARAMETERS IN VARIOUS FORMS OF THE FACIAL SKULL

The aim was to study the severity of asymmetry on different forms of the facial skull with regard to gender. It was studied 70 specially selected turtles of people of different ages from the craniological collection of the fundamental museum of the human anatomy department of the Azerbaijan Medical University. The characteristic of the group of skulls that was study was carried out on the basis of the upper index of the face. To study the asymmetry of the facial skull, the fan-shaped method of morphometry was used. The digital data of our study were subjected to statistical processing. An analysis of the data obtained indicates the absence of statistically significant sexual differences in the sizes of the contralateral sides of all the studied parameters of the upper fan for skulls with different face shapes. In the women's series on the lateral fan the asymmetry is almost negligible. In the men's series, almost all indicators on the lateral fan show stable left-sided asymmetry. The exception is the distance from the zygo-maxillary point to the lowest point of the pear-shaped hole. In the lower fan on the turtles with a narrow and broad face in the female series of skulls, left-sided asymmetry is observed in almost all signs. On turtles with a face of medium width, both significant left-sided and right-sided asymmetry are noted. In the male series, in general, the asymmetry is much less pronounced than in the female series of skulls. The exception is the subspinal-dacryon distance on wide-faced skulls in the male skull series was found right-sided asymmetry, which is not typical for the female series.

Quantification of Basin-Floor Fan Pinchouts: Examples From the Karoo Basin, South Africa

The topography of the seabed (orientation and gradient) and rheology of the flows greatly influences the character of basin-floor turbidity current deposits. Therefore, submarine fan pinchouts can help to constrain seabed topography and basin configurations at the time of deposition. Although the depositional architecture of submarine lobe pinchouts has been documented in various basin-fills, the quantification of the rates of change at pinchouts in different palaeogeographic positions and basin configurations has not been attempted previously. Here, we utilize extensive outcrops and research boreholes from the oblique up-dip pinchout of Fans 3 and 4 and the lateral pinchout of Fan 3 in the Tanqua depocentre, Karoo Basin, South Africa, to compare sedimentary facies and to quantify the rates of change in gross interval thickness. At the oblique up-dip pinchout, Fan 3 thins abruptly at a rate of 12 m/km, whilst Fan 4 thins at a rate of 4 m/km. Marked differences between Fan 3 and 4 in sedimentary facies and architecture towards the up-dip pinchout, with termination of lobes in Fan 3 and a channel-lobe transition zone and external levee in Fan 4, suggests progradation of the system. The thinning rate of the lateral pinchout of Fan 3 is 2 m/km with the presence of hybrid beds in the lower part of Fan 3, whilst the upper part is dominated by structured sandstones and thin-bedded heterolithics. The variations in facies suggest that at the lobe-scale frontal and lateral pinchouts are stacked at the lobe complex-scale lateral pinchout of Fan 3, highlighting the importance of a hierarchical understanding when studying basin-floor fan pinchouts. The quantified rates of change in fan thickness and sedimentology on the oblique up-dip and lateral fan pinchouts are markedly different. Contrasting pinchout architectures above slopes with subtle differences in gradient and orientation cautions against simple definition of reservoir input parameters for stratigraphic traps in submarine fan systems.

Growth and flowering responses of Anigozanthos hybrids influenced by plant age, temperature, and photoperiod treatments

Growth and flowering responses of Anigozanthos hybrids, ‘Regal Claw’ and A. manglesii × A. flavidus, were investigated starting from in vitro propagated propagules. Flowering of 9-week old ‘Regal Claw’ was less than 50% from the main fan (MF) when plants received 21.0°C during day and 13.0°C at night (21.0/13.0°C, day/night). Flowering of 20-week old ‘Regal Claw’ and A. manglesii × A. flavidus hybrids either from the MF or the lateral fans (LF) was accelerated when plants received 21.0/13.0°C regardless of photoperiod treatment. Flowering from the lateral fans was accelerated when plants received 8 hours of long day photoperiod (LD) treatment as a day-extension provided from incandescent light bulbs at 21.0/15.5°C and 21.0/18.0°C. Fewer than 2.5 total branches per inflorescence were produced from the MF grown at 18.0°C as compared to more than 4.0 total branches produced at 13.0°C. Plants must be 20-week old to flower from both the MF and the LF. The optimum temperature for early flowering and for an increased quality of cut flowers was considered to be 13.0°C, and at this inductive night temperature for flowering, ‘Regal Claw’ and A. manglesii × A. flavidus are considered as a day neutral, while at 15.5°C and 18.0°C, they are considered as a quantitative long day (LD) plant.

Understanding the provenance and reservoir quality of the Sele Formation sandstones of the UK Central Graben utilizing detrital garnet suites

Abstract Detrital garnet suites have been demonstrated to be reliable indicators of the mineralogical and lithological characteristics of sediment source areas. This study applies garnet analysis to the Paleocene to Eocene Sele Formation deep-water sandstone units of the central North Sea. These stratigraphic units are economically important as they represent one of the main hydrocarbon reservoir intervals in this mature basin. The routing of turbidity currents into the Central Graben has been demonstrated to be related to axial fans (ultimately sourced from Lewisian and Moine basement rocks and Triassic sandstones to the NW) and lateral fans (ultimately sourced from the Dalradian basement rocks to the west). Garnet analysis suggests the majority of samples can be attributed to the axial fan system and that the lateral system contributed little to sandstone deposition east of the Gannet Fields. This contradicts previous seismic mapping work, which suggested that the lateral fan system dominated sedimentation as far east as the Merganser Field. This reinterpretation is potentially important for our understanding of sediment routing and its impact on the distribution of reservoir quality, particularly as this is believed to relate directly to proximity to the shelf.

Rate and processes of river network rearrangement during incipient faulting: The case of the Cahabon River, Guatemala

Deeply incised river networks are generally regarded as robust features that are not easily modified by erosion or tectonics. Although the reorganization of deeply incised drainage systems has been documented, the corresponding importance with regard to the overall landscape evolution of mountain ranges and the factors that permit such reorganizations are poorly understood. To address this problem, we have explored the rapid drainage reorganization that affected the Cahabón River in Guatemala during the Quaternary. Sediment-provenance analysis, field mapping, and electrical resistivity tomography (ERT) imaging are used to reconstruct the geometry of the valley before the river was captured. Dating of the abandoned valley sediments by the ¹⁰Be-²⁶Al burial method and geomagnetic polarity analysis allow us to determine the age of the capture events and then to quantify several processes, such as the rate of tectonic deformation of the paleovalley, the rate of propagation of post-capture drainage reversal, and the rate at which canyons that formed at the capture sites have propagated along the paleovalley. Transtensional faulting started 1 to 3 million years ago, produced ground tilting and ground faulting along the Cahabón River, and thus generated differential uplift rate of 0.3 ± 0.1 up to 0.7 ±0.4 mm · y⁻¹ along the river9s course. The river responded to faulting by incising the areas of relative uplift and depositing a few tens of meters of sediment above the areas of relative subsidence. Then, the river experienced two captures and one avulsion between 700 ky and 100 ky. The captures breached high-standing ridges that separate the Cahabón River from its captors. Captures occurred at specific points where ridges are made permeable by fault damage zones and/or soluble rocks. Groundwater flow from the Cahabón River down to its captors likely increased the erosive power of the captors thus promoting focused erosion of the ridges. Valley-fill formation and capture occurred in close temporal succession, suggesting a genetic link between the two. We suggest that the aquifers accumulated within the valley-fills, increased the head along the subterraneous system connecting the Cahabón River to its captors, and promoted their development. Upon capture, the breached valley experienced widespread drainage reversal toward the capture sites. We attribute the generalized reversal to combined effects of groundwater sapping in the valley-fill, axial drainage obstruction by lateral fans, and tectonic tilting. Drainage reversal increased the size of the captured areas by a factor of 4 to 6. At the capture sites, 500 m deep canyons have been incised into the bedrock and are propagating upstream at a rate of 3 to 11 mm · y⁻¹ while deepening at a rate of 0.7 to 1.5 mm · y⁻¹. At this rate, 1 to 2 million years will be necessary for headward erosion to completely erase the topographic expression of the paleovalley. It is concluded that the rapid reorganization of this drainage system was made possible by the way the river adjusted to the new tectonic strain field, which involved transient sedimentation along the river9s course. If the river had escaped its early reorganization and had been given the time necessary to reach a new dynamic equilibrium, then the transient conditions that promoted capture would have vanished and its vulnerability to capture would have been strongly reduced.

Impacts des cônes latéraux sur le fonctionnement hydrodynamique et morphosédimentaire actuel des fonds de vallées prérifaines : cas de l'Oued Larbâa (Maroc) / Impact of lateral fans on the current hydrodynamic and morphosedimentary characteristics of valley bottoms : the case of the Larbâa wadi (Morocco)

Abstract : Impact of lateral fans on the current hydrodynamic and morphosedimentary characteristics of valley bottoms : the case of the Larbâa wadi (Morocco). Situated in a marly formation, in a region which is semi-arid and particularly sensitive to erosion processes, the valley bottom of the Larbâa wadi is marked by the presence of several lateral outwash fans of different ages. These fans operate intermittently, under the influence of exceptional rainfall events that may occur annually. With heavy rainfall, the fans invade the bed of the wadi thereby hindering its longitudinal flow. Under the pressure of heavy liquid and solid flows injected into the river by the fans, the main stream migrates across the valley bottom. As a result, the morphogenic dynamic processes show reverse trends in the meanders, leading to bank erosion and slipping on the slopes. These morphogenic processes warrant careful examination if we are to understand the present-day dynamic processes affecting deposition within fans, the changing state of fans in the valley bottom, and the flood risks they generate. The present survey analyses these impacts based on the observed relationship between climatic factors (rainfall), hydrodynamic aspects (lateral erosion, slope destabilization, etc.), sedimentary processes (granulometry, lithology and stratigraphy of deposits) and morphological aspects (types and measurements of fans, and their geometric relationship with the present alluvial plain and the actual bed of the wadi).

Abstract: Sandstones of the Antelope Shale Member, Monterey Formation, Midway-Sunset Oil Field, California 

Abstract During the late Miocene, 8.9 to 7.6 Ma, the Gabilan Range shed sediments northeast of the San Andreas fault as debris and turbidity flows depositing eight submarine-fan complexes in the southwestern San Joaquin basin encapsulated within the diatomaceous Antelope Shale Member of the Monterey Formation at Midway-Sunset Oil Field (a major mechanism causing these turbidity flows was probably movement along the San Andreas fault, in other words, the flows were seismically induced). The fans were generally time-transgressive northwestward, as the Gabilan Range was transported right laterally. The larger submarine fan members of the Monterey Formation in ascending stratigraphic order, are the Leutholtz-Metson, Williams, and Republic Sandstone Members. Minor submarine fans sourced from the southern Gabilan Range and deposited synchronously with Republic Sandstone Member deposition are the Sub-Moco, Moco T, Obispo, Uvigerina “C” and Rass. The fan morphology was controlled by 1) sand and gravel rich turbidites quickly depositing, thick sand lobes, 2) syndepositional growth folds with thicker sandstones being restricted to intraslope basin synforms, 3) lateral fan deposition, time- transgressively, due to convex fan shape and poor levees, 4) limited sediment supply between seismic and other triggering events, and 5) upper slope channel switching. The Antelope Shale sandstones are arkosic in composition, fine to coarse grained, and locally conglomeratic, depending upon whether distal, mid or proximal in original fan location. At Midway-Sunset Oil Field these submarine fan sandstones have produced more than 80 million barrels of Monterey Formation sourced oils from anticlinal, pinchout, truncation and fluid level traps.

INFLUENCE OF TEMPERATURE AND PHOTOPERIOD ON FLOWERING OF ANIGOZANTHOS HYBRIDS

Flowering responses of two Anigozanthos hybrids were investigated. Flowering of 20-week old `Regal Claw' and A. manglesii x A. flavidus either from the main fan or the lateral fans was accelerated when plants received a night temp of 13 C, regardless of the photoperiod treatments. Temperature was the major factor controlling flowering of Anigo- zanthos hybrids. Flowering was accelerated from the lateral fans by treating plants at 15.5 or 18 C and a long day (LD) photoperiod. There were fewer than 2.5 branches in the stem at 18 C compared to more than 4.0 branches at 13 C. A night temp of 13 C was optimum for early flowering and for increased quality of cut flowers. At an inductive night temp of 13 C, Anigozanthos hybrids are day neutral while at 15.5 or 18 C they are quantitative LD plants.

A Delta-Slope-Submarine Fan Model for Maestrichtian Part of Great Valley Sequence, Sacramento and San Joaquin Basins, California

Shoaling of the Great Valley fore-arc basin, which began in the northern Sacramento basin during the Campanian Stage, shifted southward in the Maestrichtian to the southern Sacramento and northern San Joaquin basins, where a regressive sequence of submarine fan, slope, and deltaic deposits aggregates 6,500 ft (2 km) in thickness. Water depth decreased to sea level as ponded submarine fans aggraded the basin floor, and slope and deltaic systems prograded basinward over them. The central part of the fore-arc basin was filled by the end of the Cretaceous; the southern part was not filled until the middle Eocene. Deltas prograded westward and southwestward from the Sierran magmatic arc. The Starkey delta system evolved from cuspate/lobate wave-dominated deltas with extensive upward-coarsening delta-front sand beds to highly lobate fluvial-dominated deltas with moderately developed delta-plain facies. This system was succeeded by elongate fluvial-dominated deltas with thick delta-plain/fluvial sequences in the Bethel Island fluvial-deltaic system. Thin, fine-grained, black, glauconitic shale beds were deposited during intervals of regional transgression and deltaic abandonment. Several progradational-transgressive cycles are recorded. The Roberts Island slope system comprises several thick shale sections deposited during progradational events. Benthic foraminifera grade upward from abundant, varied, lower bathyal species to sparse upper bathyal or neritic species. Clinoform beds that offlap from east to west are evident in electric-log cross sections and seismic profiles. Lenticular, channeled sand beds, transverse to the slope, appear to be incised slope channels that funneled sand from the delta front to submarine fans on the basin floor. Shelf-edge slumps can locally be recognized by flow folds, mudstone blocks, and anomalous thicknesses and bedding attitudes, particularly near growth faults. The Union Island submarine fan system consists of several fans; most are elongate parallel to the southeasterly trend of the basin. Fans consist of upper, middle, and lower segments. Thick-bedded, channelized, upward-fining, coarse-grained sand beds characterize the upper fan. Medium to thick-bedded, channelized, massive fine to medium-grained sand beds predominate on the midfan. Lower fan deposits are not extensive but consist of symmetrical or upward-coarsening sequences of shale and thin to medium-bedded fine to very fine sand. Channeling is less common on the lower fan. Most fans have multiple lobes, each lobe having been fed by a different delta. Gas is produced from deltaic and submarine fan deposits. Delta-front sand beds form very small reservoirs where growth faults provide subtle structural traps. Distributary-channel sand beds are highly productive, owing mainly to stratigraphic pinch-outs but locally perhaps to structural traps. Submarine fan traps have so far been located mainly in midfan deposits, either in the structurally high suprafan mounds or along lateral fan margins near the base of the slope where fan deposits onlap and pinch out against slope shale. Exploration in lower and upper fan deposits has barely begun.

Hydrocarbon-Bearing Submarine Fan System of Cellino Formation, Central Italy

The Cellino Formation is a lower Pliocene submarine fan system that forms extensive subsurface reservoir rocks. The sequence consists of interbedded sandstones and shales which crop out in central Italy; it exhibits a definite geometric pattern of lateral fan accretion. It is 60 by 20 km (37 by 12 mi), elongate NNW-SSE, and it follows the trend of previous fan systems. The vertical and lateral sequences are interpreted from electric logs and supported by field observations. The Cellino Formation consists of a series of different turbidite facies associations which includes a lower basin-plain fan edge, overlain by outer fan and fringe facies associations. The lower part of the Cellino Formation here has been cut and deeply eroded in the northern part. A new sequence follo s, which activates the eastern migration of the fan system and deposits facies. Postdepositional deformation (compressional faulting and folding) decreases in the area in intensity eastward. Carbonate cements sandstone layers in the southwest part of the area. Associated hydrocarbons were trapped in outer fan lobes which were deformed into an anticline. The thin shale beds provide the cap rocks of the turbidite reservoirs. Many of the depositional lobes have their individual gas-water contacts.

Les alluvions et le creusement quaternaires de la BasseTinée (Alpes-Maritimes )

The lower valley of Tinée River, near Clans, points out the remnants of five alluvial nivels or lateral fans. Petrographical composition, granulometry and degrees in alteration of these deposits are examined. It seems possible to give them ages of the alpine Quaternary statigraphy — Gunz (?), Mindel, Riss, Würm — in correlation with Riviera deposits. Tinée Glacier advanced to the Bancairon site during the Riss Age. Sequences of digging and filling in the main valley and its tributaries are defined for each cold period.