Unravelling the Tectonically Controlled Stratigraphy of the West Natuna Basin by Means of Palaeo-Derived Mid Tertiary Climate Changes

Author(s):  
Robert J. Morley
Keyword(s):  
2010 ◽  
Vol 74 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Georg Stauch ◽  
Frank Lehmkuhl

AbstractGeomorphological mapping revealed five terminal moraines in the central Verkhoyansk Mountains. The youngest terminal moraine (I) was formed at least 50 ka ago according to new IRSL (infrared optically stimulated luminescence) dates. Older terminal moraines in the western foreland of the mountains are much more extensive in size. Although the smallest of these older moraines, moraine II, has not been dated, moraine III is 80 to 90 ka, moraine IV is 100 to 120 ka, and the outermost moraine V was deposited around 135 ka. This glaciation history is comparable to that of the Barents and Kara ice sheet and partly to that of the Polar Ural Mountains regarding the timing of the glaciations. However, no glaciation occurred during the global last glacial maximum (MIS 2). Based on cirque orientation and different glacier extent on the eastern and western flanks of the Verkhoyansk Mountains, local glaciations are mainly controlled by moisture transport from the west across the Eurasian continent. Thus glaciations in the Verkhoyansk Mountains not only express local climate changes but also are strongly influenced by the extent of the Eurasian ice sheets.


The book asks to what extent Himalayan farmers and their institutions are prepared to face a future when external production conditions change. Because farming is particularly sensitive to climate, the main aim here is to relate present farming practices to projected future climate changes. Intensive, coordinated studies of six farming communities along the Himalayan range, from China in the east to Pakistan in the west, focus on their potentiality to adapt to climate changes that are projected for 2030, 2050, and 2100. But since climate projections are just projections, and since the context of farming is wider than just climate, the book also asks about farmers’ capacity to adapt to uncertainty in general. For that purpose, theories of ‘flexibility’ that have been applied in ecology, economics, and management science are accommodated to the present topic of farming systems. The assertion is that farmers and farming systems that are flexible are best prepared to face a future of climate change and other uncertainties.


2020 ◽  
Vol 131 (3) ◽  
pp. 487-504
Author(s):  
Eduardo Marabuto ◽  
Francisco Pina-Martins ◽  
Maria Teresa Rebelo ◽  
Octávio S Paulo

Abstract The Mediterranean region is an extremely complex hotspot where, since the Miocene, extensive geological, habitat and climate changes have taken place, alternating between warm and cold periods. These phenomena have taken a toll on the genetic composition of species, and surviving lineages have often adapted locally and diverged to the point of (complete) speciation. To study these phenomena, in this study we used one of the most enigmatic butterflies, the Portuguese dappled white, Euchloe tagis, a west Mediterranean endemic with fragmented, morphologically differentiated populations whose status have long been disputed. Even its affiliations with other Anthocharidini are largely unresolved. We used mitochondrial and nuclear markers under a phylogenetic and phylogeographical framework to evaluate its placement among relatives and population differentiation, reconstructing its evolutionary history. We found that this species had a Miocene origin ~15 Mya and was nearest to Euchloe s.s. and Elphinstonia. Its populations showed high genetic diversity but all coalesced to 5.3 Mya, when European and all but one African population diverged. Our multiple findings concerning the evolution of E. tagis through a changing, narrow habitable area might provide a more general perspective on how species survive within this hotspot of paramount importance.


2019 ◽  
Vol 9 (15) ◽  
pp. 8429-8440 ◽  
Author(s):  
Takashi Yamamoto ◽  
Yoshiaki Tsuda ◽  
Koji Takayama ◽  
Reiko Nagashima ◽  
Yoichi Tateishi ◽  
...  

2017 ◽  
Author(s):  
Rony R. Kuechler ◽  
Lydie M. Dupont ◽  
Enno Schefuß

Abstract. The Pliocene is regarded as a potential analogue for future climate with conditions generally warmer-than-today and higher-than-preindustrial atmospheric CO2 levels. Here we present the first orbitally resolved records of continental hydrology and vegetation changes from West Africa for two Pliocene time intervals (5.0–4.6 Ma, 3.6–3.0 Ma). Our results indicate that changes in local insolation alone are insufficient to explain the full degree of hydrologic variations. Generally two modes of interacting insolation forcings are observed: during eccentricity maxima, when precession was strong, the West African monsoon was driven by summer insolation; during eccentricity minima, when precession-driven variations in local insolation were minimal, obliquity-driven changes in the summer latitudinal insolation gradient became dominant. This hybrid monsoonal forcing concept explains orbitally-controlled tropical climate changes, incorporating the forcing mechanism of latitudinal gradients for the Pliocene, which probably increased in importance during subsequent Northern Hemisphere glaciations.


Author(s):  
O. Mudroch ◽  
J. R. Kramer

Approximately 60,000 tons per day of waste from taconite mining, tailing, are added to the west arm of Lake Superior at Silver Bay. Tailings contain nearly the same amount of quartz and amphibole asbestos, cummingtonite and actinolite in fibrous form. Cummingtonite fibres from 0.01μm in length have been found in the water supply for Minnesota municipalities.The purpose of the research work was to develop a method for asbestos fibre counts and identification in water and apply it for the enumeration of fibres in water samples collected(a) at various stations in Lake Superior at two depth: lm and at the bottom.(b) from various rivers in Lake Superior Drainage Basin.


1964 ◽  
Vol 2 (01) ◽  
pp. 6-12
Keyword(s):  
The West ◽  

In the West Nile District of Uganda lives a population of white rhino—those relies of a past age, cumbrous, gentle creatures despite their huge bulk—which estimates only 10 years ago, put at 500. But poachers live in the area, too, and official counts showed that white rhino were being reduced alarmingly. By 1959, they were believed to be diminished to 300.


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