Morphogenetic Environment Research Articles

An inclusive anatomical network analysis of human craniocerebral topology.

The human brain's complex morphology is spatially constrained by numerous intrinsic and extrinsic physical interactions. Spatial constraints help to identify the source of morphological variability and can be investigated by employing anatomical network analysis. Here, a model of human craniocerebral topology is presented, based on the bony elements of the skull at birth and a previously designed model of the brain. The goal was to investigate the topological components fundamental to the craniocerebral geometric balance, to identify underlying phenotypic patterns of spatial arrangement, and to understand how these patterns might have influenced the evolution of human brain morphology. Analysis of the craniocerebral network model revealed that the combined structure of the body and lesser wings of the sphenoid bone, the parahippocampal gyrus, and the parietal and ethmoid bones are susceptible to sustain and apply major spatial constraints that are likely to limit or channel their morphological evolution. The results also showcase a high level of global integration and efficient diffusion of biomechanical forces across the craniocerebral system, a fundamental aspect of morphological variability in terms of plasticity. Finally, community detection in the craniocerebral system highlights the concurrence of a longitudinal and a vertical modular partition. The former reflects the distinct morphogenetic environments of the three endocranial fossae, while the latter corresponds to those of the basicranium and calvaria.

Modularity and community detection in human brain morphology.

Humans possess morphologically complex brains, which are spatially constrained by their many intrinsic and extrinsic physical interactions. Anatomical network analysis can be used to study these constraints and their implications. Modularity is a key issue in this framework, namely, the presence of groups of elements that undergo morphological evolution in a concerted way. An array of community detection algorithms was tested on a previously designed anatomical network model of the human brain in order to provide a detailed assessment of modularity in this context. The algorithms that provide the highest quality partitions also reveal general phenotypic patterns underlying the topology of human brain morphology. Taken together, the community detection algorithms highlight the simultaneous presence of a longitudinal and a vertical modular partition of the brain's topology, the combination of which matches the organization of the enveloping braincase. Specifically, the longitudinal organization is in line with the different morphogenetic environments of the three endocranial fossae, while the vertical arrangement corresponds to the distinct developmental processes associated with the cranial base and vault, respectively. The results are robust and have the potential to be compared with equivalent network models of other species. Furthermore, they suggest a degree of concerted topological reciprocity in the spatial organization of brain and skull elements, and posit questions about the extent to which geometrical constraints of the cranial base and the modular partition of the corresponding brain regions may channel both evolutionary and developmental trajectories.

Quantification of cliff retreat in coastal Quaternary sediments using anatomical changes in exposed tree roots

AbstractSea cliffs represent 80% of the world's coasts and can be found virtually in all types of morphogenetic environments. Most studies on rocky environments focused on the impacts of modern sea level rise on cliff stability derived from sequential surveys, direct measurements or erosional features in anthropogenic structures. In this study, we explore the potential of dendrogeomorphic techniques to quantify multidecadal changes in coastal environments on Porquerolles Island (France). We sampled a total of 56 cross‐sections from 16 Pinus halepensis Mill. roots growing on former alluvial deposits and on sandy‐gravelly cliffs to quantify mean annual cliff retreat rates as well as changes in cliff geometry. Anatomical changes in roots have been used successfully in the past to quantify continuous denudation rates on slopes, channel incision and gullying processes but the approach has not been used so far in a coastal cliff context. At Porquerolles Island, reconstructed rates of cliff retreat cover 30–40 years and show average erosion rates between 0.6 and 3.9 cm yr−1 (average: 2.1 cm yr−1). Highest rates are observed at Pointe de la Tufière (2.6–3.9 cm yr−1), a small rock promontory that is more exposed to wave and storm surges than the remainder of the study area. By contrast, lower erosion rates are recorded at cliffs protected by the La Courtade pocket beach (0.6–1.9 cm yr−1). This contribution demonstrates that dendrogeomorphic analyses of roots clearly have a significant potential and that they are a powerful tool for the quantification of multidecadal rates of cliff retreat in areas where measurements of past erosion are lacking. More specifically, the approach also has clear advantages over the shorter time series obtained with repeat monitoring (e.g. terrestrial laser scanning, sensors, erosion pins) or over longer, but more coarsely resolved records obtained from aerial photographs or radio‐nuclides. © 2018 John Wiley & Sons, Ltd.

中国・内モンゴル自治区西部における地形形成環境と土地利用

中国・内モンゴル自治区西部における地形形成環境と土地利用

中国・内モンゴル自治区西部における地形形成環境と土地利用

中国・内モンゴル自治区西部における地形形成環境と土地利用

Chapter 16 The rock coasts of polar and sub-polar regions

Abstract Polar and subpolar coasts are distinctive owing to the presence of ice on land as permafrost, ground ice and glacier ice, and in the sea as tidewater glaciers, icebergs, ice shelves and sea ice. Most of these coasts remain glaciated or are recently deglaciated so their geomorphology carries a strong glacial signature. The morphogenetic environment of polar and subpolar coasts is dominated by extreme seasonality with winter development of sea ice and a shore-fast ice foot that excludes wave activity and is primarily protective. However, sea ice may also be erosional at any time of year but is most effective as an erosional agent on polar coasts between freeze-up and break-up, when wave activity forces sea ice to repeatedly impact the shore. Depending on latitude, the short summers are characterized by wave and sea ice erosion at high latitudes and by wave activity at lower latitudes. The contribution of frost weathering to cliff and shore platform development in polar and subpolar rock coasts is unclear, but is likely to be an important influence. Rock coasts are widespread in the Arctic and sub-Arctic, including Iceland, and in the Antarctic and sub-Antarctic the limited ice-free coast is almost entirely rock-dominated.

Iizuna-Kamitaru a tephra into the sediment in the middle of ITINOKURASAWA valley at Mt.Tanigawa and its the morphogenetic environments

Iizuna-Kamitaru a tephra into the sediment in the middle of ITINOKURASAWA valley at Mt.Tanigawa and its the morphogenetic environments

Estudio de algunos procesos pedogenéticos en el valle de Ojos Negros, Baja California, México

El estudio sistemático de suelos en Baja California, México, ha sido pobremente desarrollado. Solamente se han encontrado algunos reportes en la literatura científica, realizados en el Desierto Central. El objetivo de este trabajo es estudiar los procesos pedogenéticos que han permitido el desarrollo de los suelos en el valle de Ojos Negros, Baja California, bajo un ambiente mediterráneo. Para el estudio se utilizó el método jerárquico propuesto por Zinck (1988). Se estableció un ambiente morfogenético de naturaleza deposicional que permitió separar cuatro paisajes; lomeríos piedemonte, planicie de nivel de base y valle fluvial, los que fueron subdivididos por relieve/modelado y por características litológicas y sus correspondientes unidades de suelos a nivel de Gran Grupo de acuerdo con el Soil Survey Staff (1992).Estos suelos se formaron bajo diferentes ambientes, materiales, condiciones climáticas, con periodos glaciares e interglaciares de sequía y humedad. Estos procesos se iniciaron desde el Plioceno y continúan en la actualidad, manifestándose en su pedogénesis. Algunos han desarrollado horizontes Bt rojos sobre esquistos y gneiss, (Rhodoxeralfs), otros desarrollados sobre detritos graníticos, presentan un pobre desarrollo (Xeropsamments); materiales graníticos con procesos coluvio-aluvial han formado suelos poligenéticos, horizontes C, con la presencia de horizontes Bt rojos (4CBt), arcilla heredada y hierro amorfo (Haploxeralfs). Algunos otros manifiestan influencia gley (Cegz1, Gley1 6/5GY, Fluvaquents).Los procesos de erosión, transporte y acumulación de materiales en las tierras bajas continúan a la fecha, asimismo, la presencia de un proceso relativamente reciente: materiales que están siendo redistribuidos por el viento y depositados sobre diques de metarriolita, provocado por las condiciones de sequía en toda la región.

Periglacial features in Patriot Hills, Ellsworth Mountains, Antarctica

This work describes periglacial features identified at Patriot Hills, at the southernmost part of Ellsworth Mountains, Antarctica, during the 2008/2009 Brazilian Antarctic Expedition, and discusses their morphogenetic environment. Identified periglacial features were classified into: (a) rock glacier-like landform; (b) slightly creeping debris-mantled slopes; (c) steep debris-mantled slopes; and (d) rock falls. Results obtained from sediment sample analysis suggest activity and passive movement of a rock glacier-like landform, albeit minimal. Wind seems to play an important role in Patriot Hills local geomorphology. Periglacial features such as slightly creeping debris-mantled slope appear to have preferred slope orientation. They are commonly found onto slopes where the katabatic wind flows down. Slopewash and groundwater movement processes may be limited or non-existent since most snow disappears through sublimation

Shore platforms: a neglected coastal feature?

This review identifies four themes in shore platform research: 1) the role of marine and subaerial processes in platform development; 2) morphology of shore platforms; 3) modelling platform development; and 4) measuring rates of erosion. The view that shore platforms have a wave-cut origin has dominated the literature in the last 20 years. It is argued that this wave-cut origin remains to be convincingly demonstrated. Attempts to link platform morphology with the process environment have proven difficult but a recent demarcation between platform morphologies based on wave erosion and rock resistance offers an interesting and new way to consider platform morphology. Attempts to model platform development have been handicapped by a lack of data and a clear understanding of development processes. All models are based on the premise that platforms have a wave-cut origin, yet this has not been adequately demonstrated. There are a number of contradictions between models that require resolution. Erosion rates have been measured using the micro-erosion meter, but these studies are restricted both temporally and spatially. The contribution of microscale erosion relative to other forms and scales remains unknown. A number of issues are raised and suggested as being suitable questions for future research. It is proposed that real advances in understanding shore platforms will be aided by collaborative work between researchers from a number of morphogenetic environments.

Morphogenetic Environments of Japanese Mountains in the Late Quaternary

Japanese mountains have been elevated at the rate of 0.5-2.0mm/year in the global climatic flactuations during the mid-late Quaternary, and the geomorphic processes acted on the mountain slopes have also been alternated with climatic changes as well as uplift of the mountains.Changes of the morphogenetic environment of the late Quaternary in Japanese mountains are considered by means of palaeoglacier curve (Emiliani, 1978) compared to snow line and timberline (Lower limit of periglaciation) fluctuation curve in the mountainsand superposed the growth rates of the mountains on it (Fig. 1).Judging from fig. 1 the rapidly uplifted high mountains have been successively placed in periglacial environment since the middle Pleistocene, and lee side mountains of the snow bearing winter westeries were glaciated in the last glaciation and probably penultimate glaciation. Snowy, wind ward mountains near Japan Sea coast were possibly glaciated not only in the last two glaciations but also earlier ones. Evidences of penultimate glaciations are found in some mountains mainly in the snowy Japan Sea slope.Intermediate mountains of 1000-2500m (lower than 1500m in Hokkaido) in hight were situated in the periglacial environment during the last glaciation. Vast block slopes were developed under permafrost conditions in the less snow-covered mountain slopes especialy in northen and eastern Hokkaido at the time. On the contray, snowy mountains were dissected by snow-patch erosion and snow avalanche, and debris derived from slopes were transported by rapid streams fed by snow meltwater to the piedmont and alluvial fans developed there.Low mountains less than 1000m in hight have not yet been placed in periglacial environment. Low relief erosion surfaces or initial surfaces of mountains are most widely distributed in these low mountains and secondly in the block covered intermediate mountains and secondly in the block covered intermediate mountains due to feeble fluvial activity. Morphogenetic environments in Japanese mountains during the last glaciation are compiled as Fig. 3.

Intertidal forms produced by floating ice in Vestfirdir, Iceland

Forms produced by the action of intertidal ice in the fjord of Kaldalon, Vestfirdir, Iceland, are described and interpreted in terms of their morphogenetic environment. Isolated boulders resting on top of undisturbed fine sediments are interpreted as dropstones from floating intertidal ice following rockfall events. Boulder pavements and ridges which occur in the upper intertidal zone are related to the onshore movement of ice packing and bulldozing boulders together. The occurrence of such ice-formed features in Kaldalon is attributed to their preservation within a low-energy environment in spite of a limited ice-climate. The paucity of such forms preserved in the sedimentary record suggests that opportunities for burial and preservation are limited except where local infill is rapid.

Shore-platform development in the South Shetland Islands, Antarctica

Shore platforms in the South Shetland Islands, Antarctica, display morphological differences from mid-latitude platforms that are explicable in terms of the morphogenetic environment. These differences include marked horizontality of the platform surface terminated abruptly by low-tide and high-tide gradient changes. Since the processes of ice freezing-on, quarrying by impact and abrasion are responsible for such horizontality the platforms are widest in areas of restricted fetch where ice persists longest. In exposed locations, wave quarrying and abrasion limit the development of horizontality. Stratigraphic evidence suggests that the shore platforms of the South Shetland Islands are inherited features that have been rapidly retrimmed by polar shore processes. Some suggestions for future research are made.

Ice-formed Intertidal Boulder Pavements In The Sub-Antarctic

ABSTRACT Boulder pavements are flat, tightly packed mosaics of ice-smoothed and striated boulders that occur in low gradient intertidal and lacustrine areas in polar regions. In the sub-Antarctic, intertidal boulder pavements are located in three morphogenetic environments spanning l0° of latitude. Some boulder pavements are composed of ice-pushed or ice-rafted boulders which have been forced into the substrate by the pressure of grounding ice blocks. Other pavements may result from wave-winnowing of glacial till at sea level which has been subsequently modified by grounding ice. Shallow depressions in the pavement surface may correspond to the loci of large grounded ice blocks, and this interpretation is supported by striation and boulder orientations on the ridges between the depressions The occurrence of the pavement appears to depend on the following factors: a) a boulder supply; b) frequent onshore movement of floating ice; and c) a low-gradient intertidal zone. Given such conditions, the degree of development of the pavement seems to be controlled by the frequency of onshore ice movement because the best formed pavements occur in areas subject to the highest frequencies of freely moving floating ice. The occurrence of raised pavements in the South Shetland Islands suggests that little morphogenetic change has occurred in the area since 9,000 years ago. Radiocarbon dating indicates that where the frequency of ice grounding is relatively low, periods in excess of 200 years are necessary for pavement development, whereas at locations where the ice-grounding frequency is high, pavements are well formed within 300 years.

Chronology and evolution of landforms during the late quaternary in the Tokachi Plain and adjacent areas, Hokkaido, Japan

The succession of various geomorphological processes associated with climatic fluctuations in the late Quaternary and their effects on the landform of the Tokachi Plain are discussed using chronological data on glacial landforms, marine terraces, river terraces, fossil periglacial phenomena and mass movements on the mountain slopes, together with analytical data on the terrace deposits, present river deposits and slope deposits. Three major stages are recognized in the landform evolution after about 60 000 years B.P.. The division of stages is based on the chronology of the fluvial and marine terraces. The stage of the KoI terrace (60 000 – 35 000 or 30 000 years B.P.) is marked by the maximum extent of cirques in the Hidaka Range, vigorous periglacial mass movements on the mountain slopes, and by conspicuous fluvial accumulation in the regions of alluvial fan and upper reaches of each river. This fluvial accumulation seems to have occurred under glacial and periglacial morphogenetic environments. The stage of the KoII — KoIII terraces (35 000 or 30 000 – 10 000 years B.P.) is characterized by the restriction of the glaciers in the Hidaka Range, active solifluction processes on the mountain slopes, remarkable periglacial phenomena, especially sand dune development and involutions, on the terrace surfaces of the Tokachi Plain and a deep incision due to depression in sea level in the lower reaches of the Tokachi River. The stage of the KoIV terrace (10 000 years B.P. — Present) is characterized by wholly different events from the former stages, such as vigorous incision of rivers into the alluvial fans and mountainous regions, accumulation of thick alluvium in the lower reaches of the Tokachi River, and recovery of vegetation on the mountain slopes. Aufgrund von Untersuchungen der Chronologie des vergletscherten Gebietes, der marinen und fluvialen Terrassen, der fossilen Periglazialerscheinungen einschließlich periglazialer Massenbewegung auf den Hängen, sowie aufgrund entsprechender sedimentlogischen Untersuchungen wurde die Abfolge der verschiedenen geomorphologischen Prozesse, die von den Klimaschwankungen während des Jungquartärs gesteuert wurden, sowie Auswirkungen auf die Reliefentwicklung der Tokachi-Ebene diskutiert. Es können drei Hauptabschnitte in der geomorphologischen Entwicklung der letzten 60 000 Jahre unterschieden werden. Diese Abschnitte sind aufgrund der Chronologie der fluvialen Terrassen ausgeschieden worden. Der KoI-Abschnitt (60 000 bis 35 000 oder 30 000 vor heute) ist durch den größten Vorstoß der Kargletscher im Hidaka-Gebirge, durch periglaziale Massenbewegungen auf den Hängen und durch mächtige Schotterakkumulationen auf den Schwemmfächern und in den Flußtälern gekennzeichnet. Der KoII — KoIII-Abschnitt (35 000 oder 30 000 bis 10 000 vor heute) ist durch den Rückzug der Kargletscher im Hidaka-Gebirge, durch starke Solifluktionsaktivität auf den Hängen, durch periglaziale Erscheinungen, besonders Sanddünen und Kryoturbationen auf den Terrassenoberflächen der Tokachi-Ebene und durch die Tieferosion im unteren Laufbereich des Tokachi, die von der Meerregression verursacht wurde, gekennzeichnet. Der KoIV-Abschnitt (10 000 — Gegenwart) ist gegenüber den vorhergegangenen Abschnitten durch vollkommen unterschiedliche geomorphologische Prozesse sowie ausgeprägte Tieferosion auf den Schwemmfächern und in den Flußtälern, Akkumulation im unteren Laufbereich des Tokachi und durch die Wiederbesiedlung des Gebirges mit einer geschlossenen Vegetationsdecke gekennzeichnet.

GLACIAL AND PERIGLACIAL MORPHOGENETIC ENVIRONMENTS AROUND THE HIDAKA RANGE IN THE WÜRM GLACIAL AGE

In the former paper (Hirakawa & Ono, 1974), the authors described the landform evolution of the Tokachi Plain. I t was revealed that the landform evolution of the Tokachi Plain had been controlled by the sea level changes in the lowest reaches of the Tokachi River and by the climatic changes in the alluvial fan areas or the upper reaches. The conspicuous valley filling and expansion of alluvial fans occurred in the Tokachi Plain, when the glacial extent reached its maximum in the Hidaka Range (Poroshiri Stadial). Whereas neither deposition nor downcutting was remarkable inthe alluvial fan areas and the upper reaches, when the glaciation was much less extensive in the Hidaka Range (Tottabetsu Stadial). In order to clarify the interrelationship between the glaciation and the landform evolution in the plain, it is necessary to reconstruct the morphogenetic environments of the whole region. In the present paper, the authors intend the reconstruction of the morphogenetic envi-ronments around the Hidaka Range during the Wurm Glacial age, through the study of glacial or periglacial landforms, fossil periglacial phenomena, and the analysis of terrace gravels and slope deposits, and also by pollen analysis. Without these syntheses, it is impossible to relate many fragmental data, and to ex-plain them in accordance. Through the study of glacial topography, two stadials of gla-ciation are established, contrary to the generally held view that the older glacial topogra-phy is correlated to the Riss Glacial in age. The climatic conditions suggested by the glaciation of these two stadials are in good agreement with those which are suggested by the analysis of terrace gravels and slope deposits at the same time. During each Stadial, glacial extent, slope development, fluvial process and periglacial phenomena of this region were quite different, as described below: 1) Poroshiri Stadial This Stadial is characterized by the largest extension of the glacier, the abundant supply of muddy slope deposits in the Hidaka. Range and the construction of filltop terraces/allu-vial fans in the plain. As the snow line depression estimated from the glacial topography is 1200- 1500 m, the whole area of the range should have been beyond the timber line. The lowering of the timber line caused an increase in debris supply, especially from the valley walls. The filltop terrace gravels are smaller in diameter and poorer in roundness compared with the gravels of the present river bed (Fig. 12). Though there are few fossil periglacial phenomena in the earlier part of this stadial, ice-wedge cast and many involu-tions are observed in the later part (Fig. 16). 2) Tottabetsu Stadial Glaciation in the Hidaka Range was much more limited in extension than that of the Poroshiri Stadial. Glaciers occupied only a part of the large cirques excavated in the Poro-shiri Stadial (Fig. 2). The supply of slope deposits decreased. And there are no evidences of remarkable deposition nor downcutting in the area of alluvial fans. A number of dunes were distributed all over the Tokachi Plain, and the structures such as ice-wedge cast, involutions and other periglacial phenomena were developed. These facts allow the authors to deduce the morphogenetic environments of each stadial as follows. The climate of the Poroshiri Stadial was favorable to the extension of the glacier ; much snow in winter and cool in summer. On the other hand, the climate of the Tottabetsu Stadial was dry and cold especially in winter (Fig. 16).

Slopes and Their Development in an Ice-Free, Arid Area of Antarctica

In the ice free valleys of southern Victoria Land, Antarctica post-glacial modification of valley walls has extended over the last 3.5 million years, at least. There is no evidence of warmer or more humid conditions than exist at present and it is suggested that salt weathering processes in the inland areas and frost shattering and solifluction near the coast have produced bedrock (Richter) rectilinear slopes at a nearly constant angle of 35°. Slope recession has produced tent-like ridges which are the product of landform development in this type of frigid, arid, morphogenetic environment. It has not yet been determined what landforms replace the tent-like ridges in the evolutionary sequence.