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CAROLYN V. PROROK 《Geographical review》2003,93(3):283-307
ABSTRACT. Transplanting pilgrimage traditions, or the process of remaking the collective self in sacred places, requires new sacred places as worthy destinations. As people migrate from the lands where sacred places developed to those where such places may become only a distant memory, many communities attempt to recover their pilgrimage tradition by co‐opting sacred sites of host communities, maintaining links to their homeland, or re‐creating sacred sites in the lands of resettlement through replication, (re)recognition, creating movable rituals, celebrating sites of sacred embodiment, and ritual historicizing. Examples taken primarily from Catholic and Hindu experiences in the Western Hemisphere illustrate this preliminary typology. Transplanting pilgrimage traditions may be viewed as anchoring our individual, existential quests to fleeting ships of “collective selfhood.” 相似文献
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Near Williams Lake, in the central interior of British Columbia, the Fraser River exposes long sections of late Pleistocene glaciolacustrine sediments selectively preserved within a bedrock trough. The dominant facies types are thick, normally graded gravels and sands that occupy steeply dipping multistorey channels up to 300 m wide and several tens of metres deep. Channels appear to have been simultaneously cut and filled by high density turbidity currents in a glacial lake floored by stagnant ice. Fining upward sediment gravity flow sequences up to 50 m thick may be the product of quasi-continuous ‘surging’ turbidity flows triggered by catastrophic meltwater discharges into the trough or retrogressive failure of ice-cored sediments. Large-scale post-depositional deformation structures, such as synclinal folds, normal faults, sedimentary dyke swarms and dewatering structures, record gravitational foundering of sediment and pore-water expulsion caused by the melt of underlying glacier ice. Melting of buried ice masses along the floor of the trough appears to have controlled the flow paths of turbidity currents by producing sub-basins within the overlying sediment pile. An idealized model of ‘supraglacial’ lacustrine sedimentation is developed that may be applicable to other glaciated areas with similar bedrock topography. 相似文献
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The Paraná Basin (1 600 000 km2) is the largest intracratonic basin in southern South America and contains a thick (1300 m) Permo-Carboniferous glacial succession (the Itararé Group). This paper describes over 1700 m of drill core recovered during recent exploration for oil and gas. Itararé Group sediments consist of massive and stratified diamictites interbedded with massive and graded sandstones, and massive and laminated mudstones. Facies are interpreted as the product of sediment gravity flows in a glacially influenced marine basin. Three stratigraphic formations can be defined across the basin, each consisting of a lowermost sandstone-rich member overlain by a diamictite-rich member. Examination of Itararé Group rocks both in core and outcrop shows that depositional processes were influenced by active faulting and downslope resedimentation on relatively steep and unstable substrate slopes. Primary glacial deposits such as tillites and associated striated pavements occur along the present eastern outcrop belt which probably coincided with the eastern basin margin during deposition of the Itararé Group. Ice masses fringing the eastern (southern African) and western (Bolivian) basin margins supplied sediment to the basin in the form of fluvio-glacial deltas, fans and floating ice tongues. This sediment was then resedimented downslope as debris flows and turbidites. Both stratigraphic relationships and the regional distribution of facies types identify a clear pattern of basin subsidence and step-wise expansion by outward faulting within Late Proterozoic mobile belts. The position of successive basin margins can be related to specific lineament structures in the underlying basement. Asymmetric expansion of the Paraná Basin occurred along the northern and southern basin margins during deposition of the Itararé Group; this expansion probably reflects shallow crustal adjustments activated by collisional movements along the Andean margin of South America during the Hercynian Orogeny. 相似文献
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Petrology of glacial sand: implications for the origin and mechanical durability of lithic fragments
The petrology of first cycle (unmodified) and second cycle (reworked) sand at the termini of eleven valley glaciers eroding coarse- to fine-grained bedrock types is determined in order to evaluate the origin and mechanical durability of lithic sands. First cycle sands are coarse- to medium-grained, poorly sorted, fine-skewed, non-modal lithic sands with an average composition of Q21F6L73. Grain-size distributions do not vary with composition or source rock types, although sands derived from finer grained source rocks contain more lithic fragments than sands from coarser grained sources. By contrast, second cycle sands are medium-grained, poorly sorted, fine- to coarse-skewed arkosic to lithic sands with an average composition of Q19F40L41, and contain fewer lithic fragments than do first cycle sands. We propose that the origin, mechanical durability and survival potential of lithic fragments are related to the types and abundances of their internal planes of weakness, and the particular stress field of the transporting medium. As a result of abrasion, glacial clasts and lithic fragments are subjected to shear stress so that fractures propagate along intracrystal and intercrystal planes of weakness resulting in a continuous grain-size spectrum of lithic fragments and monomineralic grains irrespective of the type of source rock. Upon subsequent aqueous transport in the proglacial environment lithic fragments are subjected to point-loading during saltation in addition to shear stress. Point-loading produces extensional fractures which preferentially propagate along intercrystal planes of weakness, so the lithic fragments break into smaller monomineralic grains and/or lithic fragments. Lithic fragments of very coarse sand-size are abundant in first cycle sands, thus refuting, at least for glacial sands, the widely held view that grains of this size are deficient in nature. The presence of fewer grains of this size in second cycle sands indicates that very coarse sand-size lithic fragments can survive recycling, but in greatly reduced proportions due to breakage. 相似文献
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Coastal exposures of Late Pleistocene sediments deposited after 19 000 yr BP near Dublin, Ireland, provide a window into the infill of a subglacially-cut tunnel valley. Exposures close to the steeply dipping bedrock wall of the valley show boulder gravels within multi-storey U-shaped channels cut and filled by subglacial meltwaters driven by a high hydrostatic head. Gravels are truncated by poorly sorted ice-proximal glaciomarine sediments that record the pumping of large volumes of subglacial debris along the tunnel valley to a tidewater ice sheet margin. The sedimentary succession is dominated by sediment gravity flow facies comprising interbedded diamict and massive, poorly sorted gravel facies interpreted as subaqueous debris flow deposits. Gravel beds show local inverse and normal coarse-tail graded facies recording the restricted development of turbulent flow. Sediment gravity flow deposits fill broad (<2 km) shallow (10 m) and overlapping channels. Penetrative deformation structures (e.g. dykes) are common at the base of channels. The same subglacially-eroded topography and glaciomarine infill stratigraphy can be identified on high resolution seismic profiles across nearly 600 km2 of the western Irish Sea. Tunnel valleys are argued to have been exposed to glaciomarine processes by the rapid retreat of a calving tidewater ice sheet margin in response to marine flooding caused by glacio-isostatic downwarping below the last British Ice Sheet. The facies associations described in this paper comprise an event stratigraphy that may be found on other glaciated continental shelves. 相似文献
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NICK EYLES CAROLYN EYLES JOHN MENZIES JOE BOYCE 《Boreas: An International Journal of Quaternary Research》2011,40(1):92-104
Eyles, N., Eyles, C., Menzies, J. & Boyce, J. 2010: End moraine construction by incremental till deposition below the Laurentide Ice Sheet: Southern Ontario, Canada. Boreas, 10.1111/j.1502‐3885.2010.00171.x. ISSN 0300‐9483. Just after 13 300 14C a BP in central Canada, the retreating Ontario lobe of the Laurentide Ice Sheet briefly re‐advanced westwards through the Lake Ontario basin to build a large end moraine. The Trafalgar Moraine (27 km long, 4 km wide) is composed of a distinctly red‐coloured silt‐rich till (Wildfield Till, up to 16.5 m thick) formed by the reworking of proglacial lake deposits and soft shale bedrock. The moraine has a pronounced ramp‐like longitudinal form passing upglacier into fluted till resting on exposed shale. Analysis of water well stratigraphic data, drilled sediment cores, downhole gamma‐ray logs and exposures in deep test pits shows that within the moraine the Wildfield Till is built of superposed beds up to 7 m in thickness. These are inferred to result from the repeated incremental deposition of fine‐grained debris being moved towards the ice margin as a deforming bed such as identified at modern glaciers. A total till volume of 0.81 km3 was produced in a very brief time‐span along a transport path probably no greater than 10 km in length. Subglacial mixing of pre‐existing sediment and soft shale was clearly a very effective process for generating and moving large volumes of till to the ice margin. Similar till‐dominated end moraines occur widely around the margins of the Great Lake basins, where the markedly lobate margin of the retreating Laurentide Ice Sheet re‐advanced repeatedly into proglacial lakes and over fine‐grained sediment. This suggests the wider applicability of the till transport and incremental depositional model presented here. 相似文献
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CORNELIA WINGUTH DAVID M. MICKELSON EILIV LARSEN JESSICA R. DARTER CAROLYN A. MOELLER KNUT STALSBERG 《Boreas: An International Journal of Quaternary Research》2005,34(2):176-185
Winguth, C., Mickelson, D. M., Larsen, E., Darter, J. R., Moeller, C. A. & Stalsberg, K. 2005 (May): Thickness evolution of the Scandinavian Ice Sheet during the Late Weichselian in Nordfjord, western Norway: evidence from ice-flow modeling. Boreas , Vol. 34, pp. 176–185. Oslo. ISSN 0300–9483.
Results from experiments with a two-dimensional ice-flow model, applied along a west-east transect in western Norway, provide new constraints on the thickness evolution of the Scandinavian Ice Sheet throughout the Late Weichselian glaciation and deglaciation. Investigations took place along an E-W flowline of the former ice sheet at c. 62N, from the modern glacier Jostedalsbreen, through the Nordfjord, and across the continental shelf. A paleoclimate record from Kråkenes, which is located directly at the flowline, provides temperature and precipitation information for the time between 13 800 and 9200 cal. yr BP. LGM climate conditions for the study area are estimated from various GCM studies. The GISP2 δ18 O record has been tuned to the local data in order to provide a continuous temperature record as input for time-transgressive model runs. The results of all experiments suggest that the ice did not cover the highest mountain peaks in this area, and that nunataks persisted throughout the Late Weichselian glaciation. These findings are in contrast to results from many previous model studies and other ice-sheet reconstructions, but agree well with minimum thickness estimates from cosmogenic dating and with vertical ice limits inferred from lower block field boundaries and trimlines. 相似文献
Results from experiments with a two-dimensional ice-flow model, applied along a west-east transect in western Norway, provide new constraints on the thickness evolution of the Scandinavian Ice Sheet throughout the Late Weichselian glaciation and deglaciation. Investigations took place along an E-W flowline of the former ice sheet at c. 62N, from the modern glacier Jostedalsbreen, through the Nordfjord, and across the continental shelf. A paleoclimate record from Kråkenes, which is located directly at the flowline, provides temperature and precipitation information for the time between 13 800 and 9200 cal. yr BP. LGM climate conditions for the study area are estimated from various GCM studies. The GISP2 δ