Southeast Asian Deltas

2005 ◽  
Author(s):  
Colin D. Woodroffe
Keyword(s):  
Southeast Asia ◽  
Sea Level ◽  
Late Quaternary ◽  
River Mouth ◽  
Intensive Farming ◽  
Poor Access ◽  
Large Populations ◽  
The Many ◽  
The Individual ◽  
Modern Landscape

Deltas and estuaries are actively evolving suites of landforms formed where rivers meet the sea. Deltas are characteristically subaerial (and subaqueous) sediment wedges that protrude from the shoreline, whereas estuaries are typically tidally influenced lower parts of rivers in which the shoreline recedes inland. However, the individual distributaries of deltas, which may themselves be cuspate, exhibit estuarine characteristics, and it is convenient to use the term ‘deltaic–estuarine’ to describe river mouth tidal and alluvial plains. There are extensive low-lying coastal and deltaic–estuarine plains throughout Southeast Asia. These represent productive and relatively easily settled land, which has led to clearance of the natural vegetation of many of these plains for agriculture, silviculture, or settlement. Deltaic–estuarine plains are geologically young, responding to Late Quaternary sea-level and climatic fluctuations, and actively undergoing change in the modern landscape. Most have adopted their present form only in the past few thousand years, and are still active centres of deposition. Worldwide expansion of deltas occurred in the early to mid-Holocene as a result of deceleration of postglacial sea-level rise and the coincidence of sea level with extensive low-gradient shorelines (Stanley and Warne 1994). The formation of deltaic–estuarine plains in semi-arid areas may have been a catalyst for the appearance of civilizations based upon cultivation (Stanley and Warne 1993). Deltas in Southeast Asia, however, presented major challenges to pre-technical societies, as a result of their propensity to flood, poor access across the many bifurcating channels, and malaria, and were slower to be colonized (Büdel 1966). However, they have subsequently become important areas supporting large populations, particularly as a result of successful management of inundation for the cultivation of rice (van de Goor 1966). Overbank flooding is a prominent feature of most deltas and assures nutrient re-enrichment of fertile, but immature, soils supporting intensive farming. On the other hand, such flooding can also represent a major hazard, damaging property and in some cases resulting in loss of life. It is often controlled, or control over the extent of flooding is sought through engineering works.

scholarly journals Nonlinear response of the Antarctic Ice Sheet to late Quaternary sea level and climate forcing

2019 ◽  
Vol 13 (10) ◽  
pp. 2615-2631 ◽  
Author(s):  
Michelle Tigchelaar ◽  
Axel Timmermann ◽  
Tobias Friedrich ◽  
Malte Heinemann ◽  
David Pollard
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Ice Sheet ◽  
Volume Changes ◽  
Antarctic Ice Sheet ◽  
Glacial Ice ◽  
Ice Volume ◽  
Global Sea Level ◽  
The Individual ◽  
The Antarctic

Abstract. Antarctic ice volume has varied substantially during the late Quaternary, with reconstructions suggesting a glacial ice sheet extending to the continental shelf break and interglacial sea level highstands of several meters. Throughout this period, changes in the Antarctic Ice Sheet were driven by changes in atmospheric and oceanic conditions and global sea level; yet, so far modeling studies have not addressed which of these environmental forcings dominate and how they interact in the dynamical ice sheet response. Here, we force an Antarctic Ice Sheet model with global sea level reconstructions and transient, spatially explicit boundary conditions from a 408 ka climate model simulation, not only in concert with each other but, for the first time, also separately. We find that together these forcings drive glacial–interglacial ice volume changes of 12–14 ms.l.e., in line with reconstructions and previous modeling studies. None of the individual drivers – atmospheric temperature and precipitation, ocean temperatures, or sea level – single-handedly explains the full ice sheet response. In fact, the sum of the individual ice volume changes amounts to less than half of the full ice volume response, indicating the existence of strong nonlinearities and forcing synergy. Both sea level and atmospheric forcing are necessary to create full glacial ice sheet growth, whereas the contribution of ocean melt changes is found to be more a function of ice sheet geometry than climatic change. Our results highlight the importance of accurately representing the relative timing of forcings of past ice sheet simulations and underscore the need for developing coupled climate–ice sheet modeling frameworks that properly capture key feedbacks.

How Quaternary climate changes build and erode sedimentary deposits in an intraplate large fluvial system: the São Francisco River, Brazil

2021 ◽  
Author(s):  
Patricia Mescolotti ◽  
Fabiano do Nascimento Pupim ◽  
Francisco Sérgio Bernardes Ladeira ◽  
André Oliveira Sawakuchi ◽  
Amanda Santa Catharina ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Great Influence ◽  
River Mouth ◽  
South Atlantic Convergence Zone ◽  
Luminescence Dating ◽  
Northeastern Brazil ◽  
Tectonic Activity ◽  
Quaternary Climate ◽  
And Sea Level

<p>Climate, tectonic and sea level factors contribute to the geomorphic evolution of large rivers. Rivers draining settings where the tectonic activity and sea level influence are minors allow clearer signals from climate variation to be identified. Thus, rivers that run exclusively in tectonically quiescent areas and away from coastal regions are the most suitable targets to understand the climate drivers. In northeastern Brazil, the São Francisco River is one of the largest cratonic rivers in South America, with an extension of 2,900 km, and its thousand years evolution is registered by Quaternary deposits preserved as terraces. With the upper course in semi-humid settings, the São Franciscos flows northward, but with a watershed mostly under semi-arid conditions. Hence, the São Francisco River’s deposits are an excellent fluvial sedimentary record to shed light on how large tropical rivers responded to climatic changes of the Quaternary. We studied a 200 km stretch of the middle course of the São Francisco in the State of Bahia by using remote sensing methods and field surveys for geomorphological and sedimentological analyses combined with optically stimulated luminescence dating (OSL). We recognized at least four phases of fluvial aggradation (>90 ka; 65 to 39 ka; 18 to 9.5 ka and 380 years to recent) and three phases of incision (I1 - 85 to 65 ka; I2 - 39 to 18 ka and I3 - 9.5 to 1.0 ka). Two aggradation events and the incision event I2 are also observed in the upper course of the São Francisco River. The river incision events agree with precession insolation cycles (~25 ka) at latitude 10° S, which influence the rainfall in the area. The incision events occurred probably due to increased fluvial discharge produced by intensification of the South Atlantic Convergence Zone (SACZ), which has great influence on precipitation over the upper São Francisco river. Thus, we conclude that the aggradation-incision cycles of the São Francisco River during the last 100 ka are likely products of millennial precipitation variation, possibly related to precession cycles. The events of high sedimentation rate in the São Francisco river mouth are partially correlated with incision phases in its middle course. This suggests that sedimentation in plains of large plateau rivers can be decoupled from the coastal area.</p><p><strong>Keywords</strong>: Late Quaternary, fluvial response, OSL dating, aggradation-incision cycles, precession cycles</p>

Climatic and sea level controls on Late Quaternary eolian activity on the Agulhas Plain, South Africa

2006 ◽  
Vol 65 (02) ◽  
pp. 252-263 ◽  
Author(s):  
Andrew S. Carr ◽  
David S.G. Thomas ◽  
Mark D. Bateman
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Coastal Dunes ◽  
Coastal Dune ◽  
Published Data ◽  
Fluvial Systems ◽  
Groundwater Levels ◽  
Rainfall Seasonality ◽  
The Individual ◽  
Induced Changes

AbstractLocated at the interface between the temperate westerly and sub-tropical climate systems, South Africa's winter rainfall zone (WRZ) is a key location in understanding Late Quaternary atmospheric circulation dynamics. Inactive eolian deposits in the WRZ, comprising pan-fringing lunette and coastal dunes, were investigated to establish their depositional ages and utility as paleoenvironmental indicators. The resulting optical luminescence chronology reveals episodic lunette accretion at 60,000–45,000 yr, 12,000–13,000 yr, 2800–2600 yr, 1200 yr, and <1000 yr, with coastal dune ages clustering at 4100–4700 yr.Episodes of lunette and coastal dune accretion on the Agulhas Plain are temporally distinct, reflecting differing fundamental controls on their activity. Comparisons to previously published data also reveal that the lunettes differ in age from more ancient coastal eolianites. Lunette deposition is asynchronous between locations, reflecting the topographic and hydrological setting of the individual pans. In near-coastal settings, with limited surface recharge, lunette accretion appears to be at least partially controlled by sea level induced changes in groundwater levels. Those pans with more significant surface recharge (particularly from fluvial systems) may produce less ambiguous paleoenvironmental records, with pan status more strongly reflecting regional hydrological conditions. Lunette orientation is indicative of strong westerly winds during both the Pleistocene and Holocene. Lunette accretion would have been promoted by reduced on-shore moisture transport during the summer months, enhancing rainfall seasonality. Such conditions would have been promoted by increased continentality as the Agulhas Bank was exposed during low sea level stands.

Quaternary Sea Level Fluctuations on a Tectonic coast: New 230Th/234U Dates from the Huon Peninsula, New Guinea

1974 ◽  
Vol 4 (2) ◽  
pp. 185-205 ◽  
Author(s):  
A.L. Bloom ◽  
W.S. Broecker ◽  
J.M.A. Chappell ◽  
R.K. Matthews ◽  
K.J. Mesolella
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
New Guinea ◽  
Tectonic Uplift ◽  
Reef Complex ◽  
Sea Level Fluctuations ◽  
Uplift Rates ◽  
The Mean ◽  
The Difference ◽  
The Individual

Emerged coral reef terraces on the Huon Peninsula in New Guinea were reported in a reconnaissance dating study by Veeh and Chappell 1970. Age definition achieved was not good for several important terraces, and we report here a series of new 230Th/234U dates, which further clarify the history of late Quaternary eustatic sea level fluctuations. More than 20 reef complexes are present, ranging well beyond 250,000 yr old: we are concerned with the seven lowest complexes. Major reef-building episodes dated by 30Th/234U are reef complex I at 5–9 ka (kilo anno = 1000 yr), r.c. IIIb at 41 ka (four dates), r.c. IV at 61 ka (four dates), r.c. V at 85 ka (two dates), r.c. VI at 107 ka (two dates), and r.c. VII at 118–142 ka. Complex II was previously dated by 14C at 29 ka: this age has not yet been confirmed, and may be only a lower limit. The reef crests were built during or immediately before intervals of sea level maxima, when rates of rising sea level and tectonic uplift briefly coincided. The culmination of each reef-building episode was only a few thousand years in duration, and multiple dates from the same reef complex generally group within the statistical errors of the individual dates.Several methods can be used to estimate the altitude of each sea level maximum relative to present sea level. The least complicated is to calculate mean tectonic uplift rate for each profile of the terraces, and use the mean rate to calculate the tectonic displacement of each dated reef complex on that profile. The difference between the present altitude of a reef complex and its calculated tectonic uplift gives the paleosea level at the time the reef grew. We estimate uplift rates for six surveyed sections by calibrating against published paleosea level estimates from Barbados and elsewhere, viz 125 ka, paleosea at +6 m; 103 ka, −15 m; 82 ka, −13 m. For each section the individual uplift rates for reefs V, VI, and VIIb are within 5% of their section means. Using the mean rates. paleosea level estimates for reef crests II, IIIB, and IV are made for each section. Consistency of estimates between sections is good, giving −28 m for the 60 ka paleosea level, around −38 m for the 42 ka level and −41 m for the 28 ka level (if the age is older the paleosea level would be lower. Using the mean uplift rates, the 82 ka and 103 ka paleosea levels are also estimated for each section: all individual estimates are plotted graphically, and a sea level curve drawn. The reef stratigraphy indicates sea level lowerings between each dated reef crest: the crests probably represent the interstadials of the Wisconsin (Würm, Weichsel) Glaciation, and intervening lower levels correspond to stadials. Since the last time of eustatic sea level higher than the present (about 125 ka), five sea level maxima occurred at roughly 20-ka intervals, none being as high as the present.

Whither the people in the ASEAN Community?

2020 ◽  
Vol 10 (3) ◽  
pp. 43-57
Author(s):  
See Seng Tan
Keyword(s):  
Southeast Asia ◽  
Political Ideology ◽  
Management Development ◽  
The Other ◽  
Asean Member ◽  
Derechos Humanos ◽  
The People ◽  
Droits Humains ◽  
The One ◽  
The Individual

Abstract: The longstanding effort to develop a people-based regionalism in Southeast Asia has been shaped by an inherent tension between the liberal inclination to privilege the individual and the community under formation, on the one hand, and the realist insistence on the primacy of the state, on the other. This article explores the conditions and constraints affecting ASEAN’s progress in remaking Southeast Asia into a people-focused and caring community in three areas: disaster management, development, and democratization (understood here as human rights). Arguably, the persistent gap in Southeast Asia between aspiration and expectation is determined less by political ideology than by the pragmatic responses of ASEAN member states to the forces of nationalism and protectionism, as well as their respective sense of local and regional responsibility.Resumen: El esfuerzo histórico para desarrollar un regionalismo basado en las personas del sudeste de Asia ha estado marcado por una tensión fundamental entre la inclinación liberal de privilegiar el individuo y la comunidad y la insistencia realista sobre la primacía del estado. Este artículo explora las condiciones y limitaciones que afectan el progreso de la ASEAN en la reestructuración de Asia sudoriental en una comunidad centrada en el cuidado de las personas en: gestión de desastres, desarrollo y democratización (i.e., derechos humanos). La brecha persistente en el sudeste asiático entre la aspiración y la expectativa está determinada por las respuestas pragmáticas de los miembros de la ASEAN sometidos a las fuerzas del nacionalismo y proteccionismo, así como su respectivo sentido de responsabilidad local y regional.Résumé: L’effort historique pour développer un régionalisme fondé sur les peuples en Asie du Sud-Est a été marqué par une tension fondamentale entre l’inclination libérale qui privilégie, d’une part, l’individu et la communauté et, d’autre part, l’insistance réaliste sur la primauté de l’État. Cet article explore les conditions et les contraintes qui nuisent aux progrès de l’ANASE dans le cadre d’une refonte de l’Asie du Sud-Est en une communauté centrée et attentive aux peuples dans trois domaines : la gestion des désastres, le développement et la démocratisation (en référence aux droits humains). Le fossé persistant en Asie du Sud-Est entre les aspirations et les attentes est vraisemblablement moins déterminé par l’idéologie politique que par les réponses pragmatiques des États membres de l’ANASE soumis aux forces du nationalisme et du protectionnisme ainsi que par leur sens respectif de la responsabilité locale et régionale.

A Handbook to Eddic Poetry: Myths and Legends of Early Scandinavia, ed. Carolyne Larrington, Judy Quinn, and Brittany Schorn. Cambridge: Cambridge University Press, 2016, xii, 413 pp., 12 b/w ill.

Mediaevistik ◽  
2018 ◽  
Vol 31 (1) ◽  
pp. 366-366
Author(s):  
Albrecht Classen
Keyword(s):  
Old Norse ◽  
Entire Volume ◽  
Cambridge University ◽  
Critical Studies ◽  
Individual Contributions ◽  
The Many ◽  
The Individual ◽  
Made In ◽  
Scandinavian Literature

Eddic poetry constitutes one of the most important genres in Old Norse or Scandinavian literature and has been studied since the earliest time of modern-day philology. The progress we have made in that field is impressive, considering the many excellent editions and translations, not to mention the countless critical studies in monographs and articles. Nevertheless, there is always a great need to revisit, to summarize, to review, and to digest the knowledge gained so far. The present handbook intends to address all those goals and does so, to spell it out right away, exceedingly well. But in contrast to traditional concepts, the individual contributions constitute fully developed critical article, each with a specialized topic elucidating it as comprehensively as possible, and concluding with a section of notes. Those are kept very brief, but the volume rounds it all off with an inclusive, comprehensive bibliography. And there is also a very useful index at the end. At the beginning, we find, following the table of contents, a list of the contributors, unfortunately without emails, a list of translations and abbreviations of the titles of Eddic poems in the Codex Regius and then elsewhere, and a very insightful and pleasant introduction by Carolyne Larrington. She briefly introduces the genre and then summarizes the essential points made by the individual authors. The entire volume is based on the Eddic Network established by the three editors in 2012, and on two workshops held at St. John’s College, Oxford in 2013 and 2014.

LATE QUATERNARY SEA-LEVEL HIGHSTANDS OF THE MID-ATLANTIC US COASTAL PLAIN AND SUB-ORBITAL VARIABILITY WITH IMPLICATIONS FOR ICE SHEET SENSITIVITY

2016 ◽  
Author(s):  
Robert K. Poirier ◽  
◽  
Thomas M. Cronin ◽  
Thomas M. Cronin ◽  
Miriam E. Katz ◽  
...  
Keyword(s):  
Sea Level ◽  
Coastal Plain ◽  
Late Quaternary ◽  
Ice Sheet

Individuality and Beyond

2019 ◽  
Author(s):  
Benedetta Zavatta
Keyword(s):  
Moral Autonomy ◽  
First Line ◽  
Philosophical Interpretation ◽  
Individual Personality ◽  
The World ◽  
Regulative Ideal ◽  
Personal Library ◽  
The Many ◽  
The Individual ◽  
The Impact

Based on an analysis of the marginal markings and annotations Nietzsche made to the works of Emerson in his personal library, the book offers a philosophical interpretation of the impact on Nietzsche’s thought of his reading of these works, a reading that began when he was a schoolboy and extended to the final years of his conscious life. The many ideas and sources of inspiration that Nietzsche drew from Emerson can be organized in terms of two main lines of thought. The first line leads in the direction of the development of the individual personality, that is, the achievement of critical thinking, moral autonomy, and original self-expression. The second line of thought is the overcoming of individuality: that is to say, the need to transcend one’s own individual—and thus by definition limited—view of the world by continually confronting and engaging with visions different from one’s own and by putting into question and debating one’s own values and certainties. The image of the strong personality that Nietzsche forms thanks to his reading of Emerson ultimately takes on the appearance of a nomadic subject who is continually passing out of themselves—that is to say, abandoning their own positions and convictions—so as to undergo a constant process of evolution. In other words, the formation of the individual personality takes on the form of a regulative ideal: a goal that can never be said to have been definitively and once and for all attained.

scholarly journals Differential Influences of Teleconnections from the Indian and Pacific Oceans on Rainfall Variability in Southeast Asia

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 886
Author(s):  
Abdul Azim Amirudin ◽  
Ester Salimun ◽  
Fredolin Tangang ◽  
Liew Juneng ◽  
Muhamad Zuhairi
Keyword(s):  
Indian Ocean ◽  
Southeast Asia ◽  
El Niño ◽  
El Nino ◽  
Rainfall Variability ◽  
June July August ◽  
Rainfall Patterns ◽  
Negative Impacts ◽  
The Individual ◽  
June July

This study investigates the individual and combined impacts of El Niño and the positive Indian Ocean Dipole (IOD) on the Southeast Asia (SEA) rainfall variability. Using composite and partial correlation techniques, it is shown that both inter-annual events have individually distinct impacts on the SEA rainfall anomaly distribution. The results showed that the impacts of the co-occurrence of El Niño and IOD events are significant compared to the individual effects of pure El Niño or pure IOD. During June-July-August and September-October-November, the individual impacts of the pure El Niño and IOD events are similar but less significant. Both events caused negative impacts over the southern part of SEA during June-July-August (JJA) and propagated northeastward/eastward during September-October-November (SON). Thus, there are significant negative impacts over the southern part of SEA during the co-occurrence of both events. The differential impacts on the anomalous rainfall patterns are due to the changes in the sea surface temperature (SST) surrounding the region. Additionally, the differences are also related to the anomalous regional atmospheric circulations that interact with the regional SST. The anomalous Walker circulation that connects the Indian Ocean and tropical Pacific Ocean also plays a significant role in determining the regional anomalous rainfall patterns.

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