Modern Elevation Research Articles

WAYS TO STABILIZE THE CONDITION OF THE TRANSPORTATION OF AGRICULTURAL PRODUCTS IN THE CONDITIONS OF LARGE-SCALE RUSSIAN AGGRESSION

The issue of transportation of agricultural products from the producer to the buyer is important for our country. Russia's full-scale war against Ukraine emphasized the extreme importance of the transport complex for the economy and society. With the beginning of invasion of Ukrainian land, air communication with the world was completely stopped, and sea ports were also blocked. With the beginning of hostilities on the territory of Ukraine, the routes of transportation of agricultural products were disrupted, a large number of elevators were destroyed, the road surface of warehouses was destroyed, and sea ports were seized. The purpose of this article was to study the current state of freight transportation in the conditions of martial law, to improve and stabilize the ways of transporting agricultural products. The task was to find ways to improve logistics and ways to protect grain products from missile strikes, as well as possible ways to export this grain from the territory of Ukraine. The article presents the results of an analytical analysis of the state of transportation of agricultural products, suggests ways to stabilize and solve the problem. The development of logistics and cooperation with foreign partners, the construction of protected hubs for storing grain products, as well as the construction of modern elevators that could accumulate large volumes of products for their further transportation in large batches to consumers. The best option for Ukraine would be the creation of grain hubs in European countries, as well as transport grain by motor vehicle, accumulate grain in large batches, and deliver it to other parts of the world, through the ports of Europe. However, today it is not so easy, because currently European countries are imposing restrictions on the import of our grain products. Today, despite the difficult military situation, the lost part of the transport infrastructure and logistics, Ukraine is one of the largest grain exporting countries. The restoration of traditional ways of freight transportation and the constant search for new ones is a sign of a healthy and promising policy for the development of the transport industry. The European choice of our state, the support of partners will ensure uninterrupted freight transportation and will give new impetus to the development of river and railway transport.

Differential paleoelevation changes in North China during the late Mesozoic: Evidence from stable isotopes and clumped isotopes

The modern elevation of China decreases from the Tibetan plateau in the west to near sea level in the east across several topographic steps. A pronounced topographic step occurs in North China (NC), separating the plateaus and high mountains (elevations generally >1000 m) that dominate western NC from the plains and low mountain landscapes (elevations generally <500 m) of eastern NC. The topographic step in NC shapes modern climate and vegetation gradients and may have affected paleoenvironments and ecosystems in deep time. However, few studies have been conducted to explore paleoenvironmental and paleoelevation changes in NC, and thus the timing of its establishment is unclear. In this study, we use δ18O, δ13C and clumped isotope values of Middle Jurassic and Early Cretaceous paleosol carbonates from representative basins in western and eastern NC to constrain paleoenvironmental and paleoelevation changes during the late Mesozoic. Our δ13C and clumped isotope results suggest that the Ordos Basin of western NC maintained high paleoelevation (>1.5 km) during the Middle Jurassic-late Early Cretaceous, while the Hefei Basin of eastern NC experienced significant elevation reduction by the Early Cretaceous. Combined with paleogeographic, geophysical, and paleoecological evidence, these findings suggest that the lowering of eastern NC may have formed a topographic step across NC by Aptian time. This topographic change may have affected paleoclimate patterns and caused a climatic transition from dry to humid in eastern NC during this period. Broader topographic and environmental change may have occurred in Eastern China during the Early Cretaceous.

Rapid topographic growth of the Taiwan orogen since ~1.3–1.5 Ma

We present the first paleotopographic reconstruction of Taiwan by measuring the hydrogen isotope composition of leaf waxes (δ 2 H n C29 ) preserved in 3-Ma and younger sediments of the southern Coastal Range. Plant leaf waxes record the δ 2 H of precipitation during formation, which is related to elevation. Leaf waxes produced across the orogen are transported and deposited in adjacent sedimentary basins, providing deep-time records of the source elevation of detrital organic matter. δ 2 H n C29 exported from the southern Taiwan orogen decreased by more than 40‰ since ~1.3–1.5 Ma, indicating an increase of &gt;2 kilometers in the organic source elevation. The increase in organic source elevation is best explained by rapid surface uplift of the southern Central Range at around ~1.3–1.5 Ma and indicates that this part of the orogen was characterized by maximum elevations of at least 3 km at this time. Further increase in organic source elevation from ~0.85 to ~0.3 Ma indicates continued topographic growth to modern elevations.

Fuzzy adaptive PID speed controller design for modern elevator traction machine

With the development of the times, elevator has become an essential transportation in our life. In order to meet the comfort of elevator operation, this paper investigates the design of the speed control system of elevator permanent magnet synchronous traction motor in combination with the elevator operation curve. The whole system is based on SVPWM and uses direct torque control combined with fuzzy adaptive PID to achieve accurate control of motor running speed. It includes the input signal module, control module, drive module and feedback module. Firstly, the analysis of each module in the system is completed, and the connection between the modules is established, as well as the control system. Then case studies are carried out on MATLAB/SIMULINK, and the actual running speed curve of the elevator is obtained, and the simulation results are analyzed to verify the stability and reliability of this speed control system and complete the design.

Automatic velocity measurement system applied to elevator overspeed governors

All around the world, modern elevators transport safely and comfortably millions of passengers and freight each day. Since modern elevators emerged at the beginning of the 19th century, several advances have risen in this transportation system. Among them, safety conditions were significantly improved. Therefore, modern elevators must be equipped with safety protection systems to assure safety conditions and avoid accidents. An overspeed governor is one of the components of such a safety system. It acts as a stopping mechanism when the elevator car reaches an excessive velocity, known as tripping speed. When the tripping speed is reached, the overspeed governor is mechanically locked and halts the rope, thus stopping the elevator car. This paper describes the development of a new measuring system able to measure the trigger velocity of an overspeed governor with the help of a graphical interface available on a mobile electronic device (smartphone or tablet). Practical application: A new overspeed governor velocity measuring system uses a mobile electronic device for non-contact velocity measurement. This new process may replace the inaccurate measuring system currently employed by maintenance technicians, thus increasing its reliability. The main objective consists of rigorously testing the operation of overspeed governors. The developed system guarantees the automatic execution of the test under several anomalous operating situations, thus allowing the user to have real-time access to the test data obtained through a graphical interface available on a mobile electronic device.

Palaeoglaciation in the Low Latitude, Low Elevation Tropical Andes, Northern Peru

Characterising glaciological change within the tropical Andes is important because tropical glaciers are sensitive to climate change. Our understanding of glacier dynamics and how tropical glaciers respond to global climate perturbations is poorly constrained. Studies of past glaciation in the tropical Andes have focused on locations where glaciers are still present or recently vacated cirques at high elevations. Few studies focused on lower elevation localities because it was assumed glaciers did not exist or were not as extensive. We present the first geomorphological evidence for past glaciations of the Lagunas de Las Huaringas, northern Peru, at elevations of 3,900–2,600 m a.s.l. Mapping was conducted using remotely-sensed optical imagery and a newly created high-resolution (∼2.5 m) digital elevation model (DEM). The area has abundant evidence for glaciation, including moraines, glacial cirques, hummocky terrain, glacial lineations and ice-sculpted bedrock. Two potential models for glaciation are hypothesised: 1) plateau-fed ice cap, or 2) valley glaciation. Assuming glaciers reached their maximum extent during the Local Last Glacial Maximum (LLGM), between 23.5 ± 0.5 and 21.2 ± 0.8 ka, the maximum reconstructed glacial area was 75.6 km2. A mean equilibrium line altitude (ELA) of 3,422 ± 30 m was calculated, indicating an ELA change of −1,178 ± 10 m compared to modern snowline elevation. There is an east to west ELA elevation gradient, lower in the east and higher in the west, in-line with modern day transfer of moisture. Applying lapse rates between 5.5 and 7.5°C/km provides a LLGM temperature cooling of between 6.5–8.8°C compared to present. These values are comparable to upper estimates from other studies within the northern tropical Andes and from ice-core reconstructions. The mapping of glacial geomorphology within the Lagunas de las Huaringas, evidences, for the first time, extensive glaciation in a low elevation region of northern Peru, with implications for our understanding of past climate in the sub-tropics. Observations and reconstructions support a valley, rather than ice cap glaciation. Further work is required to constrain the timing of glaciations, with evidence of moraines younger than the LLGM up-valley of maximum glacier extents. Numerical modelling will also enable an understanding of the controls of glaciation within the region.

Crustal Thickening of the Northern Central Andean Plateau Inferred From Trace Elements in Zircon

AbstractThe timing of crustal thickening in the northern Central Andean Plateau (CAP), at 13–20°S, and its relationship to surface uplift is debated. Zircon qualitatively records crustal thickness as its trace element chemistry is controlled by the growth of cogenetic minerals and relative uptake of light and heavy Rare Earth Elements. Jurassic to Neogene zircons from volcanic rocks, sandstones, and river sediments reveal shifts in trace element ratios suggesting major crustal thickening at 80–55 Ma and 35–0 Ma, coincident with high‐flux magmatism. An intervening magmatic lull due to shallow subduction obscures the magmatic record from 55 to 35 Ma during which thickening continued via crustal shortening. Protracted thickening since the Late Cretaceous correlates with early elevation gain of the CAP western margin, but contrasts with Miocene establishment of near modern elevation in the northern CAP and the onset of hyperaridity along the Pacific coast, highlighting their complex spatial and temporal relationship.

Holocene sea levels at the Gulf of Aqaba, northern Red Sea

A new relative sea level (RSL) curve is presented for the Holocene Gulf of Aqaba, northern Red Sea. The curve is based on U–Th ages of corals retrieved from leveled fossil reefs comprising the Tur Yam Terrace at the shore of the city of Elat, Israel and the Aqaba reef terraces, Jordan, located respectively east and west of the northern tip of the gulf. Both terrace tops are submerged under high tide and subaerial at low tide. The fossil corals are in growth position between two beachrock units. The corals comprise 100% aragonite, show pristine textures with no secondary aragonite cements and yield initial 234U/238U activity ratios of 1.146 ± 0.004, similar to the values of live corals and modern Gulf of Aqaba (GoA) waters. Sixteen U–Th ages of corals from the Tur Yam Terrace span the time interval of 6.8 to 5.5 ka, and are ordered along the growth direction of the terrace. Detailed mapping of the terrace, the distribution of corals’ genera and the order of their ages on the terrace, suggest that the exposed terrace was the back reef/lagoon zone, a very close to shore environment of a fringing reef. Identification of this reef zone was based on a detailed ecological study that we conducted on the Nature Reserve Reef (NRR), a modern fringing reef located several hundred meters to the south. A morpho-tectonic analysis of the Elat shore indicates that the Tur Yam Terrace lies on top of the footwall of the active Elat Fault and has remained at its original level, with negligible vertical shift. Thus, it appears that during the time interval of formation of the Tur Yam corals, sea level at GoA reached a maximum stand that was 1–2 m above the modern elevation. A similar figure is shown by Mid-Holocene corals from the Aqaba fossil reefs and shore indicators from the Red Sea. The relative sea level (RSL) curve deduced from the Gulf of Aqaba corals and from the Red Sea indicators resembles those of precisely-dated stable reefs off west and east Australia and a few other well dated reefs in the Indo-Pacific. This similarity calls for coeval response of the Indo-Pacific oceans to ice melting during the early to mid- Holocene, and a similar pattern of decline to the present level during the late Holocene. Such a coeval rise of distant parts of the Indo-Pacific oceans is consistent with dominance of melt waters releases over the oceans with minor effects of all other “sea level drivers".

An integrated mathematical method for traffic analysis of elevator systems

The present study proposes a new analytical method for traffic analysis of modern elevator systems. The method analyzes probabilistically the complete operation of any configuration of modern directional collective elevator systems, for any combination of building type and architecture and passenger traffic pattern and demand. It presents very low computational cost and it produces results that can be used for a complete evaluation of the service performance and for a further detailed energy consumption analysis of the elevator system being analyzed.The method is structured in four discrete calculation modules that have been programmatically implemented and cooperate through a numerical iterative procedure that converges providing the final average operation state of the elevator system.

Elevator group control as a constrained multiobjective optimization problem

Modern elevator systems are controlled by the elevator group controllers that assign moving and stopping policies to the elevator cars. Designing an adequate elevator group control (EGC) policy is challenging for a number of reasons, one of them being conflicting optimization objectives. We address this task by formulating a corresponding constrained multiobjective optimization problem, and, in contrast to most studies in this domain, approach it using true multiobjective optimization methods capable of finding approximations for Pareto-optimal solutions. Specifically, we apply five multiobjective optimization algorithms with default constraint handling techniques and demonstrate their performance in optimizing EGC for nine elevator systems of various complexity. The experimental results confirm the scalability of the proposed methodology and suggest that NSGA-II equipped with the constrained-domination principle is the best performing algorithm on the test EGC systems. The proposed problem formulation and methodology allow for better understanding of the EGC design problem and provide insightful information to the stakeholders involved in deciding on elevator system configurations and control policies.

Holocene sea-level change and estuary infill in North West Nelson, central New Zealand

The sedimentary sequences found within estuaries in the north west Nelson region of central New Zealand are investigated in order to quantify the timing of the end of the Post Glacial Marine Transgression. This region has been identified as being relatively stable in terms of vertical tectonic movement during the Holocene, but is yet to yield any reconstructions of eustatic sea level. In this study, we investigate the Holocene infill of a barrier estuary (Parapara Inlet) through sedimentological analysis and radiocarbon dating of 18 vibracores up to 4.2 m in length. It is found that the estuary infilled through a combination of lateral flood tide and fluvial delta progradation as well as vertical central basin infill. The central basin infilled at a consistent rate of 0.4 mm/year in both the mid (7.0–6.0 ka) and late-Holocene (2.5–1.5 ka). By the time of early human (Maori) settlement (c. 1 ka), the estuary surface was at low intertidal elevations with sediment being transported from the fluvial to tidal delta. A discernible change in sedimentation rates could not be associated with Maori settlement; however, infill rates increased to at least 12.5 mm/year in the past 150 years due hydraulic sluicing associated with mining. The sedimentary history of Parapara Inlet is compared to nearby Whanganui Inlet, d’Urville Island and Nelson to establish the character of regional Holocene sea level movement. It is found that relative sea level reached modern elevations between 8 and 7 ka in the region. The similarity between sea level curves for the end of the post glacial marine transgression (PMT) to other tectonically stable sites in northern New Zealand suggests that this curve can now be considered a true eustatic signal for the New Zealand archipelago.

Identification of seasonal varves in the lower Pliocene Bouse Formation, lower Colorado River Valley, and implications for Colorado Plateau uplift

Abstract The cause of Cenozoic uplift of the Colorado Plateau is one of the largest remaining problems of Cordilleran tectonics. Difficulty in discriminating between two major classes of uplift mechanisms, one related to lithosphere modification by low-angle subduction and the other related to active mantle processes following termination of subduction, is hampered by lack of evidence for the timing of uplift. The carbonate member of the Pliocene Bouse Formation in the lower Colorado River Valley southwest of the Colorado Plateau has been interpreted as estuarine, in which case its modern elevation of up to 330 m above sea level would be important evidence for late Cenozoic uplift. The carbonate member includes laminated marl and claystone interpreted previously in at least one locality as tidal, which is therefore of marine origin. We analyzed lamination mineralogy, oxygen and carbon isotopes, and thickness variations to discriminate between a tidal versus seasonal origin. Oxygen and carbon isotopic analysis of two laminated carbonate samples shows an alternating pattern of lower δ18O and δ13C associated with micrite and slightly higher δ18O and δ13C associated with siltstone, which is consistent with seasonal variation. Covariation of alternating δ18O and δ13C also indicates that post-depositional chemical alteration did not affect these samples. Furthermore, we did not identify any periodic thickness variations suggestive of tidal influence. We conclude that lamination characteristics indicate seasonal genesis in a lake rather than tidal genesis in an estuary and that the laminated Bouse Formation strata provide no constraints on the timing of Colorado Plateau uplift.

Paleoaltimetry of the Western Andes in Northern Chile (∼18.5–19.5°S)

Establishing the timing of surface uplift in the Central Andes is essential for evaluating the geodynamic mechanisms responsible for mountain building and their role in the development of dry conditions along the western coasts of Peru and Chile. Here, we present new stable hydrogen isotopic values from stream waters and hydration water in volcanic glass from northern Chile (18.5–19.5°S) that show that the Western Cordillera was already elevated by the early Miocene. The hydrogen isotopic values of reconstructed surface waters obtained from ancient and modern volcanic glass indicate that the Western Cordillera in northern Chile attained modern elevations by at least 22.8 Ma. When combined with paleoaltimetric records from the Altiplano and northwestern Puna, these results demonstrate that surface uplift of the Andean plateau was a time-transgressive process that varied not just from west to east but also from north and south along the strike of the orogen. Our paleoaltimetry reconstruction also suggests that the Western Cordillera has blocked moisture coming from the east since at least the early Miocene, consistent with previously published evidence of arid-semiarid conditions in the Atacama Desert. However, hyperaridity on the western Andean slope developed later and appears to correspond with the timing of uplift in the Eastern Cordillera and Altiplano. Our results suggest that the growth of the Central Andean rain shadow relied not only on the elevation of the Western Cordillera but also on the widening of the plateau.

Surface uplift of the Tibetan Plateau: Constraints from isostatic effects of Cenozoic sedimentary accumulation

The surface uplift history of the Tibetan Plateau remains one of the most important unresolved issues in geosciences. Numerous models have been proposed to account for the growth of the Tibetan Plateau. This paper tries to analyze the surface uplift of the Tibetan Plateau from isostatic effects of the Cenozoic sedimentary accumulation. Based on isostatically-compensated basin infilling model, we show that the surface uplift magnitudes caused by the Cenozoic sedimentary accumulation constitute the main part of the modern elevations of the Qaidam and Tarim basins around the Tibetan Plateau, but only a small part of the modern elevations of the Hoh Xil and Lunpola basins inside the Tibetan Plateau. Paleogene sediments account for the uplift magnitudes of >900 m in both the Hoh Xil and Lunpola basins, while the uplift magnitudes caused by Neogene sediments are <100 m in these two basins. In contrast, the uplift magnitudes caused by Paleogene sediments in the Qaidam and Tarim basins around the Tibetan Plateau are relatively limited, whilst Neogene sediments contribute ~1100 m and ~700 m of their modern elevations respectively. It suggests that the central Tibetan Plateau was with high relief during the early Cenozoic, and its surface was successively flattened by erosion and basin-infilling processes. The initial uplift of the Tibetan Plateau occurred at the weak zones and the rigid blocks inside the Tibetan Plateau were gradually broken.

Oligocene Desmanthus (Leguminosae) from the Qaidam Basin in northeastern Tibetan Plateau, China, and its implications for paleoclimate and paleoelevation

ABSTRACT Fossils are critical for understanding the environmental changes and uplift history of the Tibetan Plateau during the Cenozoic. As the largest inland basin located at the northeastern plateau, Qaidam Basin has been regarded as the key region to understand the climatic changes in the plateau during the Cenozoic. Herein, fossil legumes from the Oligocene Shangganchaigou Formation in northwestern Qaidam Basin have been reported and are assigned to Desmanthus cf. virgatus (L.) Willd. based on morphological comparison. Current materials represent the first megafossil record of this genus in the world. The living analogues of current fossils now live in regions with mean annual temperature values (MAT) ranging from 13.4 to 29.1°C and mean annual precipitation values (MAP) ranging from 36 to 2874 mm while the MAT and MAP of current northwestern Qaidam Basin is −1.03°C and 60.5 mm, respectively, and indicate that the Oligocene Qaidam was much warmer than today. We calculate that current fossils could grow no higher than 2492 m considering the climatic condition of the Oligocene Qaidam. The difference between estimated and modern elevation of the fossil site suggests that the elevation of the research area has increased by at least ≈1000 m since the Oligocene.

The role of the westerlies and orography in Asian hydroclimate since the late Oligocene

Abstract Interactions between midlatitude westerlies and the Pamir–Tian Shan mountains significantly impact hydroclimate patterns in Central Asia today, and they played an important role in driving Asian aridification during the Cenozoic. We show that distinct west-east hydroclimate differences were established over Central Asia during the late Oligocene (ca. 25 Ma), as recorded by stable oxygen isotopic values of soil carbonates. Our climate simulations show that these differences are present when relief of the Pamir–Tian Shan is higher than 75% of modern elevation (∼3000 m). Integrated with geological evidence, we suggest that a significant portion of the Pamir–Tian Shan orogen had reached elevations of ∼3 km and acted as a moisture barrier for the westerlies since ca. 25 Ma.

Late Cenozoic topographic evolution of the Eastern Cordillera and Puna Plateau margin in the southern Central Andes (NW Argentina)

The Andes constitute an important orographic barrier in the southern hemisphere, impacting atmospheric circulation, the amount and distribution of rainfall, and Earth-surface processes in a highly asymmetric manner. In the Central Andes of NW Argentina, the Andean Plateau (Puna) and the intermontane basins of the adjacent Eastern Cordillera constitute geological archives that furnish spatiotemporal information on surface uplift and associated paleo-environmental change. Today, rainfall in NW Argentina is focused along the windward flanks of the Eastern Cordillera, while its intermontane basins and the Puna constitute high-elevation regions with strongly reduced rainfall. The present-day influence of these topographic characteristics on precipitation patterns is reflected by systematic changes in the hydrogen stable isotope ratios of meteoric water. Proxy archives from basin strata record past environmental conditions and provide insight into the nature of topographic growth through time. We present 34 new hydrogen isotopic compositions of volcanic glass (δDg), extracted from tuffs interbedded with the sedimentary deposits of three different regions across the eastern Andean margin between ca. 24°S and 25°S latitude. Combined with new zircon U-Pb geochronology, our data show clear spatiotemporal variations in δDg correlating with topographic growth and ensuing orographic effects during the Miocene and Pleistocene. In particular, variations in δDg indicate that the Pastos Grandes (Puna) and the Toro (Eastern Cordillera) basins had attained modern elevations by ca. 8 and 6 Ma, respectively. A strong positive shift in the δDg record of the Toro Basin after 840 ka coincides with deposition of thick fluvial/alluvial conglomerates suggesting orographically induced aridification due to progressive range uplift to the east. Other δDg records from the Eastern Cordillera show similar, but diachronous events emphasizing the importance of regional tectonics for environmental change with implications for the formation of orogenic plateaus.

Landscape and drainage evolution during the Cenozoic in the Salinas Grandes Basin, Andean Plateau of NW Argentina

Endorheic basins are distinctive features of the modern Andean plateau. These basins record thick Neogene-to-Modern evaporite successions that are considered as the onset of internal drainage and aridity. Some isolated older (Paleogene) evaporites and intermontane depocenters have been also described across the Argentine Puna, suggesting that some degree of hydrological isolation would have pre-dated the main Miocene-Pliocene plateau uplift. Evaporites beds, however, are not conclusive evidence for endorheism, given that their formation depends not only on the tectonically-driven paleo-drainage, but also on other sensitive variables as climate, and salinity of the sources. Here, we discuss the paleo-drainage evolution across the eastern Puna plateau at 23°-24° S, combining landscape numerical modeling with seismic stratigraphy. Seismic observations suggest an intermontane configuration as early as the late Paleogene, and relief formation to the east and west basin margins. Using different combinations of precipitation rates, our landscape models allowed us to reproduce the modern elevations observed in the study region as well as published thermochronological data. Our results suggest that endorheism would have started in the Paleogene, and would have dominated most (>70%) of the Cenozoic basin history. Models show the recurrence of endorheism, interrupted by intermittent phases of drainage connectivity (exorheism) to the east (foreland) in the upper half Eocene and the early Miocene. According to these results, the formation of closed basins in the Puna region would have pre-dated the main Miocene-Pliocene uplift stage of the Andean plateau.

Lithospheric thinning and dynamic uplift effects during slab window formation, southern Patagonia (45˚-55˚ S)

The southernmost South America has been affected by the subduction of an oceanic seismic ridge, which began to subduct below southern Patagonia at ∼14 Ma. This scenario led to the formation of a slab window, which is still active and where hot buoyant asthenospheric mantle produced thermal anomalies and modifications in the lithospheric thicknesses. Meanwhile, from the Patagonian Andes to the Atlantic coast, an outstanding regional surface uplift took place, conducting to a moderated-elevation plateau formation. In this work we analyzed the causes of this long-wavelength surface elevation change using residual topography and uplift rate calculations, considering paleo-lithospheric states. We achieved this considering that the study area underwent a lithospheric thickness changes through time, before and after the slab window formation. This allowed us to estimate the isostatic and dynamic adjustment over time and their influences on the surface elevation changes. These rates were compared with geological and stratigraphic observations derived from a key elevation marker bed: The modern altitudes of Oligo-Miocene marine strata top, originally deposited close or below sea level, and placed at Present at hundreds of meters above sea level. Our residual topography calculations, that result from comparing isostatic and observed topography, indicates the dynamic topography contribution in the study region was very minor (if so) to null. The isostatic uplift, in turn, shows a remarkable fitting with the reconstruction of marine marker bed, suggesting a causative relationship. We can assert that Patagonian lithospheric thinning, particularly of the lithospheric mantle, by slab window formation, would have been enough to reproduce the modern elevations and surface uplift across the plateau from the Miocene to Present day. Our work opens a question on the model that connect slab windows, asthenospheric upwelling flows with surface uplifting. However, as shown by recent works, lithospheric changes might trigger small convection cells, which might produce local and small dynamic topography.

A methodological framework for reconstructing historical delta front morphology: case study at Macquarie rivulet delta within Lake Illawarra, Australia

Reconstructing past delta front morphology is a challenging task, due to complex morphological formation processes. We have developed a methodological framework to reconstruct the delta front morphology by integrating the information from historical shorelines, spatial distribution of depositional environments, relative sea-level changes and a modern Digital Elevation Model (DEM). The delta front morphology was reconstructed based on spatial connections between mud basin morphology, subaerial DEM and the historical shoreline. In addition, available sedimentation data at the delta front was utilized to aid in reflecting complex morphological formation processes. Taking Macquarie Rivulet delta within Lake IlIawarra, Australia, as an example, we generated the historical delta morphology for 1892. The modelled sedimentation rate appears to be consistent with the measured ones. We have also applied this method to reconstruct the historical morphology in 1938 and 1981. The model results indicate a progressive infilling influenced by switching river mouth locations. The cautions and implications of this method are also discussed. An increased resolution of sedimentation data should be able to improve the accuracy of the model. The reconstructed morphologies, elucidating fundamental information about delta evolution and sediment mass volumes in the past, can be employed in management activities.