Sedimentary and structural record of the Scandinavian Ice Sheet margin dynamics at the SE part of the Głubczyce Plateau, a foreland of the East Sudetes Mountains (S Poland)
0
Citation
107
Reference
10
Related Paper
Keywords:
Bedrock
Foreland basins are important areas of exploration for petroleum in China.According to the basin construction and evolution,the foreland basins in central and western China can be divided into four types of assemblages including the presenile,the reconstructed,the regenerated and the superimposed.This paper discusses the geological conditions of accumulation,such as the assemblages of source rock,reservoir and seal,in different foreland basins based on the examples of northwestern Junggar foreland basin(the presenile),western Sichuan foreland basin(the reconstructed),northern Chaidamu foreland thrust(the regenerated) and southern Junggar foreland basin(the superimposed).The thermal evolutions of main source rocks are stated in the four types of foreland basins.The foreland development in the late period of Himalayan movement has an obvious control on the thermal evolution of source rocks in the Chaidamu foreland thrust(the regenerated) and southern Junggar foreland basin(the superimposed).
Hydrocarbon exploration
Cite
Citations (2)
Deglaciation
Glacial landform
Landform
Terminal moraine
Wisconsin glaciation
Cite
Citations (19)
The ittle ce ge behaviour of glaciers in the central ritish olumbia oast ountains, anada, was described by conducting lichenometric surveys of hizocarpon spp. found on recently deposited moraines in the itimat and acific ranges. At attullo lacier in the southern itimat ange, surveys across four sets of nested lateral moraines describe advances prior to the late thirteenth century, 1550–1610, 1680–1710, and 1850 ad. In the onarch cefield area in the northern acific ange, ittle ce ge moraines stabilized prior to 1380–1430 ad, the mid‐seventeenth and mid‐eighteenth centuries, and in the mid‐nineteenth century. The timing of these moraine‐building episodes corresponds closely to the intervals of glacier expansion recorded in complementary studies in the region. These findings indicate that most glaciers in the region reached their maximum downvalley ittle ce ge extent prior to 1780 ad, and suggest that climate forcing likely contributed to regionally synchronous glacier fluctuations.
Little ice age
Ice caps
Glacier morphology
Cite
Citations (8)
The landforms always withhold the imprints of characteristic geomorphic processes within it. In the upper reaches of Baspa valley, geomorphic records of glacial origin have been investigated for three glaciers viz., Shaune Garang glacier (North facing), Jorya Garang glacier (North facing) and Saro glacier (South facing). The field investigation was carried out for Shaune Garang glacier and extrapolated for Gor Garang and Saro glacier. This terrain is inaccessible and characterized by highly rugged and adverse climatic conditions. Visual interpretation technique of remote sensing is found to be accurate, economical and time saving, hence, the glacial landforms were mapped from Liss III + Pan merged data of IRS 1D, October 2001. The hanging valleys, terminal moraines and lateral moraines are found to be one of the important geomorphic indicators for reconstruction of paleo-glacial history of Baspa valley. The results show that maximum of three sets of lateral and terminal moraines have been identified in Shaune Garang glacier, Jorya garang shows three sets of terminal and two set of lateral moraine and Saro glacier shows one terminal moraine and two sets of lateral moraine indicating respective stages of deglaciation. The length of surface accumulation observed in above data of Oct, 2001 for Shaune Garang, Jorya Garang and Saro glacier is 3.75km, 11.6km and 1.17km respectively. Thus, it shows that south facing glaciers show minimum surface accumulation as compared to the north facing glacier and maximum three stages of deglaciation have been recorded in present study.
Deglaciation
Terminal moraine
Landform
Glacier terminus
Glacial landform
Cite
Citations (3)
Abstract 18 new radiocarbon dates were obtained for organic materials, associated mainly with soils buried by till, from sites in the lateral moraines of Mount Cook glaciers, particularly the Tasman. The 23 New Zealand (i.e., Institute of Nuclear Sciences, DSIR, Lower Hutt) dates now available from the Tasman Glacier, taken at face value, indicate that there were glacier expansion periods there about 3450-3000, 2280, 1800-1620, 1200-900, 860, 680, 340, and < 250 radiocarbon years ago. Taking into account the statistical counting error, the ages of some of the date sets overlap. Excluding a few problematical age determinations, and those on whole soil samples, the full range of dates now available from moraines of Mount Cook glaciers (including those from the New Zealand laboratory and a laboratory in Hannover, West Germany), taken at face value, shows that glacier expansion episodes have occurred: c. 8000 years ago, probably in the 6th millennium B.P., c. 3690-3000, c. 2550-2280, c. 2110-1620, c. 1255-900, c. 860, c. 680, c. 550, c. 340, and < 250 radiocarbon years ago. The dates and the associated geomorphic evidence indicate that the glacier shrinkage which ensued from about A.D. 1900 to at least A.D. 1984 has been the most profound for at least the last 3500 years.
Mount
Cite
Citations (26)
An inventory of bedrock material has been made from different levels in some moraine types situated in the areas around Storvindeln and Storavan. The results show that moraine forms which have a curved morphology transverse to the direction of ice flow, always have a high content of local bedrock material independent of till thickness. In many cases the local bedrock material is represented more in the upper levels of the moraine. Large transverse ridges with less curvature have a highly variable bedrock content. Drumlins may lack local bedrock material over a distance of many kilometres. The variable distribution of local bedrock material in different moraine types has been interpreted as a function of ice pressure, temperature, and movement during deglaciation.
Bedrock
Drumlin
Deglaciation
Cite
Citations (7)
<p>Rock walls in high-alpine glacial environments are becoming increasingly unstable due to climate warming. This instability increases the erosion of headwalls above glaciers modifying glacial surface debris cover and mass balance and, thus, affecting the response of glaciers to climate change. As debris is deposited on glaciers, it is passively transported downglacier forming medial moraines where two glaciers join.</p><p>We assess headwall erosion by systematic downglacier-debris sampling of medial moraines and by computing headwall erosion rates from their <sup>10</sup>Be-cosmogenic nuclide concentrations. Around Pigne d&#8217;Arolla in Switzerland, we collected a total of 39 downglacier medial moraine debris samples from five adjacent glaciers. We explicitly chose medial moraines with source headwalls that vary in size, orientation and morphology, to investigate how different debris source area characteristics may express themselves in medial moraine cosmogenic nuclide concentrations. At the same time, the downglacier-debris sampling enables us to derive headwall erosion rate estimates through time, as medial moraine deposits tend to be older downglacier.</p><p>Preliminary results reveal systematic differences in <sup>10</sup>Be concentrations for the studied glaciers. At Glacier d&#8217;Otemma, Glacier du Brenay, and Glacier de Cheilon <sup>10</sup>Be concentrations average at 17x10<sup>3</sup>, 31x10<sup>3</sup>, and 4x10<sup>3</sup> atoms g<sup>-1</sup>, respectively. Downglacier <sup>10</sup>Be concentrations at Glacier d&#8217;Otemma vary systematically and headwall erosion rates tend to increase towards the present. At both Glacier du Brenay and Glacier de Cheilon downglacier <sup>10</sup>Be concentrations are more uniform, suggesting that headwall erosion rates did not evolve significantly through time. Results for Glacier de Tsijiore Nouve and Glacier de Pi&#232;ce will follow soon. In addition, samples at Glacier d&#8217;Otemma were collected along two parallel medial moraines sourced by different but adjacent headwalls. Yet, their downglacier <sup>10</sup>Be concentrations deviate and our analyses suggest that at Glacier d&#8217;Otemma both differences in headwall orientation and headwall deglaciation history may account for the deviation of the two medial moraine records. For all five glaciers, we currently explore how lithology, slope angles, exposition, deglaciation, and elevation vary between the debris source areas and how differences therein could result in the observed differences in <sup>10</sup>Be concentrations.</p>
Cosmogenic nuclide
Terminal moraine
Cite
Citations (0)
<p>Glacial moraines represent one of the most spatially diverse climate archives on earth. Moraine dating and numerical modeling are used to effectively reconstruct past climate from mountain ranges at the global scale. But because moraines are often located downvalley from steep mountain headwalls, it is possible that debris-covered glaciers emplaced many moraines preserved in the landscape today.</p><p>Before we can understand the effect of debris cover on the moraine recored we need to understand how debris modulates glacier response to climate change. To help address this need, we developed a numerical model that links feedbacks between mountain glaciers, climate change, hillslope erosion, and landscape evolution. Our model uses parameters meant to represent glaciers in the Khumbu region of Nepal, though the model physics are relevant for mountain glaciers elsewhere.</p><p>We compare simulated debris-covered and debris-free glaciers and their length evolution. We explore the effect of climate-dependent hillslope erosion. We also allow temperature change to control frost cracking and permafrost in the headwall above simulated glaciers. Including these effects holds special implications for glacial evolution during deglaciation and the long-term evolution of mountain landscapes.</p><p>Because debris cover suppresses melt, debris-covered glaciers can advance independent of climate change. When debris cover is present during cold periods, moraine emplacement can lag debris-free glacier moraine emplacement by hundreds of years. We develop a suite of tools to help determine whether individual moraines were formed by debris-covered glaciers. Our analyses also point to how we might interpret moraine ages and estimate past climate states from debris-perturbed settings.</p>
Rock glacier
Terminal moraine
Deglaciation
Glacier mass balance
Cite
Citations (0)
Deglaciation
Greenland ice sheet
Ice core
Cite
Citations (53)