Permafrost Structure Research Articles

An Analysis on Frozen-Melting Behavior of Periodic Change of Surface Temperature (Continuation) (Dual Periodic Temperature Changes with Daily and Annual Cycles)

It is important to understand the frozen-melting behavior of thermal active layer in permafrost area for dual periodic temperature changes combined with daily and annual cycles. The numerical results are compared with the single cyclic change and discussed on the temperature profiles in detail. The thermal structures are revealed to be consisted of dual Stokes depths and, in consequence, the net heat fluxes at the surface are illustrated to be affected by daily cycle to a certain extent. The influences on temperature profiles due to daily cycle penetrate only in Stokes depth pertinent to its own cycle, while the entire tempkrature distributions are decided by the annual cycle. Additionally, a simple experiment is performed to demonstrate the validity of the findings, predicted in former paper, regading the temperature decreases in deep underground compared with an average (or initial) surface temperature, which is essential to form the permafrost structure.

Relic permafrost structures in the Gobi of Mongolia: age and significance

Relict permafrost structures (ice-wedge casts and cryoturbation structures) are present in the Gobi of southern Mongolia. Luminescence dates of sediments are presented to constrain the age of formation of permafrost structures. These data show that there was a phase of permafrost development during the latter part of the Last Glacial (after about 22 to 15 ka) that resulted in cryoturbated sediments and ice-wedge casts. Furthermore, permafrost degradation occurred during late Pleistocene times (13–10 ka) and was absent during the early Holocene. These permafrost structures mark the southernmost evidence of permafrost in northern Asia during late Quaternary times and indicate that the mean annual air temperature was below approximately −6°C during their formation. © 1998 John Wiley & Sons, Ltd.

Relic permafrost structures in the Gobi of Mongolia: age and significance

Relict permafrost structures (ice-wedge casts and cryoturbation structures) are present in the Gobi of southern Mongolia. Luminescence dates of sediments are presented to constrain the age of formation of permafrost structures. These data show that there was a phase of permafrost development during the latter part of the Last Glacial (after about 22 to 15 ka) that resulted in cryoturbated sediments and ice-wedge casts. Furthermore, permafrost degradation occurred during late Pleistocene times (13–10 ka) and was absent during the early Holocene. These permafrost structures mark the southernmost evidence of permafrost in northern Asia during late Quaternary times and indicate that the mean annual air temperature was below approximately −6°C during their formation. © 1998 John Wiley & Sons, Ltd.

Permafrost changes in the northern Tien Shan during the Holocene

The evolution of permafrost within the northern Tien Shan during the Holocene is described. It is based on the interpretation of a temperature curve obtained from a deep borehole in the Zhusalykezen mountain pass (3336 m ASL), located in the Zailiysky Alatau Range. This curve indicates a zone where the temperature falls as the depth increases. Such an anomaly reflects past thermal conditions in the high mountains. At present, permafrost is absent on the southern slope where the borehole was drilled. Analysis of the temperature curve indicates that warming and cooling took place during the Holocene. Maximum warming occurred about 7000–10,000 years ago when the ground temperature rose by approximately 0.5–1.5 °C. Maximum cooling was recorded in the last millennium, the ground temperature being lower than today by 1.0–1.5 °C. These fluctuations are corroborated by relict permafrost and palaeocryogenic structures © 1997 John Wiley & Sons, Ltd.

Preservation of cell structures in permafrost: A model for exobiology

The present report is the first contribution toward a comprehensive fine-structural study of microbial cells from permafrost. Prokaryotes with a variety of cell wall types demonstrate high stability of cell structure after long-term cryopreservation in frozen soils and sediments of the Arctic. The surface capsular layers that were a salient feature of the cells both in situ and on nutrient media may be an adaptation to low temperature. To the extent that permafrost regions on Earth approximate Martian conditions, preservation of cell structure there can serve as the basis for predictions about preservation in Martian permafrost sediments.

The design and construction of underground hydraulic structures in permafrost : G. Y. Gevirtz, in: Comprehensive rock engineering. Vol. 2, ed J.A. Hudson, (Pergamon), 1993, pp 501–527

The design and construction of underground hydraulic structures in permafrost : G. Y. Gevirtz, in: Comprehensive rock engineering. Vol. 2, ed J.A. Hudson, (Pergamon), 1993, pp 501–527

CHARACTERISTICS OF THE PERMAFROST STRUCTURE ON THE FILDES PENINSULA, KING GEORGE ISLAND, ANTARCTICA

Based on the data from the pitting, geoelectrical prospectings, temperature measuring, and the divided layers frost-heaving instruments, this paper, first, discusses the structure features of active layers in this region, and proves the presence of the bowl-shaped frost table in the stone circles area. Second, it analyses the temperature distributive rule in the active layer, meantime, according to the vertical-profile parameters of granularity, clay mineral, salt content and resistivities, it also discusses the different features of permafrost structure and their control actions on the periglacial landform development between high and low places. It suggests that the four-layer structure should exist in the permafrost region (including under-bedrock), that is, active layer, frost sand and gravels layer, frost volcanic rock permeated by sea water, and frost volcanic rock unpermeated by sea water. Finally, the permafrost table and its vertical gradient are deduced.

Mechanical features of underground hydraulic structures in permafrost : Gevirtz, G Y Proc ISRM Symposium on Design and Performance of Underground Excavations, Cambridge, 3–6 Sept 1984P353–359. Publ London: British Geotechnical Society, 1984

Mechanical features of underground hydraulic structures in permafrost : Gevirtz, G Y Proc ISRM Symposium on Design and Performance of Underground Excavations, Cambridge, 3–6 Sept 1984P353–359. Publ London: British Geotechnical Society, 1984

The electromagnetic response of the Assistance Bay region.

The electromagnetic response of the Assistance Bay region (N. W. T., Canada) is studied using laboratory analogue model and field station measurements. Magnetic field components for the frequency range 0.1-15Hz, which includes the well known lightning induced Schumann Resonances, were measured at 8 sites along a 6km line through the central region of Assistance Bay and roughly perpendicular to the Cornwallis Island coastline. Two of the stations were on land and six were off-shore on the ice. Although the field data were examined in the three bandwidths 0.1-6Hz, 6-10Hz, and 10-15Hz, the present work deals only with the 8Hz Schumann Resonance component within the 6-10Hz range. Calculated average amplitudes and phases of the three magnetic field components show the relative response of the region at stations along the 6km line. The response is discussed in terms of the effect of the on shore topography, the coastline, and the bathymetry.A laboratory analogue model of the Assistance Bay region was constructed and model measurements carried out for a simulated frequency of 8Hz for E-Polarization (electric field in the east-west direction) and H-Polarization (electric field in the north-south direction) of an overhead uniform horizontal inducing field. The magnetic field amplitudes Hx, Hy, Hz for both polarizations for 10 traverses perpendicular to the coastline are presented and the anomalous fields attributed to the response of the coastline bay, capes, bathymetry and source field polarization.The analogue model and the field station coast effects (vertical to horizontal field ratio) are compared for the model traverse coinciding with the 6km line of field stations. The analogue model results show a maximum enhancement of approximately 1.3 directly over the coastline with rapidly decreasing values seaward followed by a second enhancement over the sharp ocean depth gradient beyond the 55m depth contour. The field station results do not show maximum at the coastline, but rather an increasing value seaward, reaching a value of 1.7 at the station over the sharp ocean depth gradient near the 55m depth contour, indicating the effective coastline to be at the deep water edge. This difference may in part be attributed to the shallow water conductivity being smaller than simulated in the laboratory model. The effect of the 2m layer of ice, as well as the accumulation of fresh water from streams in the Assistance Bay region, may lead to a significantly lower effective conductivity than assumed for the analogue model. An effective decrease in the shallow water conductivity would lead to decreased enhancement at the coastline and relative increased enhancement off-shore at the deep water edge. Other factors possibly contributing to the seemingly anomalous seaward coast effect could be subsurface geologic and permafrost structure, and the nature of the source field. The laboratory overhead inducing source is adequate for simulating ionospheric currents of large extent but may not be suitable for the Schumann source field associated with distant lightning strokes due to lack of a significant vertical electric field component. This source field effect requires further study.

Determining the reliability of foundation beds of buildings and other structures in permafrost : Khrustalev, L N; Mirenburg, Y S Soil Mech Found Engng, V13, N4, May–June 1976, P176–180

Determining the reliability of foundation beds of buildings and other structures in permafrost : Khrustalev, L N; Mirenburg, Y S Soil Mech Found Engng, V13, N4, May–June 1976, P176–180

The palaeogeography of mid- and east Europe during the last cold stage, with west European comparisons

In this review of work on mid- and east European palaeogeography during the last cold stage the author has used a stratigraphic division based on deep-sea sediments in the Atlantic. Difficulties apparent in palaeogeographical reconstructions are discussed. In such reconstructions the sequences of permafrost structures, loesses, fossil soils, slope sheets, fluviatile sediments, vegetation, glacial deposits and land forms are analysed. The consideration of events in both their stratigraphic order (time scale) and their areal distribution in Europe has enabled the author to give a far more accurate indication of temperature and moisture changes in the different parts of Europe. Contrasts revealed by a section through east and west Europe reflect differences in the evolution of permafrost, in the succession of vegetation and soils, and in the history of glaciation. Their source was the different degree of climatic continentality which increased throughout the last cold stage. Continentality was characterized by the contemporaneous decrease in temperature, increase in temperature amplitudes and decrease in precipitation values. The presence of permafrost in Europe was responsible for the different development of biota. This makes for difficulty in reconstructing palaeogeographic conditions on the basis of actualism.

Determining the reliability of foundation beds of buildings and other structures in permafrost

Determining the reliability of foundation beds of buildings and other structures in permafrost

Impulse radar sounding in permafrost

A VHF impulse radar system operating on the ground is a viable technique for mapping the near‐surface geological structure and electrical properties of permafrost. A fixed antenna configuration transported over the surface yields a reconnaissance map of two‐way travel times for subsurface reflectors. Wide‐angle reflection and refraction (WARR) sounding determines propagation velocity versus depth when performed in layered areas. To obtain a WARR sounding, one measures travel time versus antenna separation. These techniques were field tested in the Tuktoyaktuk region of the Mackenzie River delta, N.W.T. Data recording was on a graphic display for initial field analysis and on analog magnetic tape for subsequent processing. Reconnaissance surveying has mapped structural features at various depths between 3 and 30 m. The electrical loss of the soils at a site limits the penetration depth. Clays and silts attenuate the radar signal more than sands and gravels. WARR soundings have determined dielectric constant versus depth in layered areas. While impulse radar is useful in delineating geological structure, core drilling is required to determine the geological composition.

Late Precambrian glacial climate and the Earth's obliquity

SummaryLate Precambrian (∼ 750±200 Ma) glaciogenic sequences exhibit substantial evidence for marked climatic inequability of seasonal and longer periodicity (10° to ∼ 106yrs): (1) tillites are closely associated with dolomites, limestones and evaporites apparently of warm-water origin; (2) tillites occur with red beds and iron-formations whose iron probably was derived ultimately from lateritic weathering; (3) glacial dropstones occur locally within carbonates and iron-formations; (4) laminae, interpreted asvarvesby many workers, are common in argillites, carbonates and iron-formations; and (5) permafrost structures attributable to repeated seasonal changes of temperature are locally abundant. Such climatic, particularlyseasonalinequability apparently conflicts however with the probable low (≲30°) palaeolatitudes of deposition of numerous late Precambrian glaciogenic sequences.The contradictions presented by such sequences may be resolved by postulating a considerably increased obliquity of the ecliptic (ε) in late Precambrian time. Substantial increase in e would: (1) greatly amplify global seasonality; (2) weaken climatic zonation, thus allowing warm-water sedimentation and lateritic weathering over wide latitudes; and (3) increase the ratio of radiation received annually at either pole to that received at the equator, so when 54° < ε < 126° low and middle latitudes (≤ 43°) would be glaciated in preference to the poles. Ice sheets and permafrost thus can be envisaged principally in low and middle latitudes with contiguous warm-water and iron-rich facies under a markedly seasonal climate. The concept of secular change of e is supported by other geological evidence.

Stability of unsupported underground structures in permafrost : In Russian. 2R. THERMOPHYS. MECH. MAT. NAT. MEDIA ENGNG STRUCT. AT LOW TEMP. PART 1, YAKUTSK, TA4 18.24, T48, 1974, P153-P157.

Stability of unsupported underground structures in permafrost : In Russian. 2R. THERMOPHYS. MECH. MAT. NAT. MEDIA ENGNG STRUCT. AT LOW TEMP. PART 1, YAKUTSK, TA4 18.24, T48, 1974, P153-P157.

Second international conference on permafrost

The Second International Conference on Permafrost will be held in Yakutsk, USSR, July 16–28, 1973.The conference program will include the following topics for the main sessions: Thermophysical fundamentals of the processes of the formation and development of the cryolithosphcre; regional geocryology; genesis, composition, and structure of permafrost and ground ice; physics, physico‐chemistry and mechanics of permafrost and ice; groundwater of the cryohthosphere; geocryological surveys and predicitons; and principles of controlling geocryological conditions during construction in areas of permafrost.

Evidence of Sub-Till Sediments from a Weichselian Interstadial in the Gudbrandsdalen Valley, Central East Norway

The authors point out several localities with sub-till sediments in the highly ice-eroded Gudbrandsdalen Valley. Two localities are described and discussed. Based upon studies of texture and structure, the sediments are interpreted as proglacial deposits, not removed by a later ice-advance. The assumed permafrost structures (fossil ice wedges) and 6 finds of mammoth remnants, of which one has been C14 dated to 24,400 ± 900 years B. P. (Heintz 1969), indicate that these sediments are of an interstadial age.Tentatively this is named the Gudbrandsdalen interstadial. Out of the total of 15 mammoth finds in Norway, 13 are from the Gudbrandsdalen area. The sub-till sediments were presumably the depositaries for these fossils during the latest glaciation.

Rock Folds Due to Weathering

Previous articleNext article FreeRock Folds Due to WeatheringMarius R. CampbellMarius R. Campbell Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 14, Number 8Nov. - Dec., 1906 Article DOIhttps://doi.org/10.1086/621358 Views: 29Total views on this site Citations: 2Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:B. P. Ruxton Polygonal ridge patterns on the dissected Sepik piedmont plain, New Guinea, Journal of the Geological Society of Australia 25, no.5-65-6 (Aug 2007): 285–294.https://doi.org/10.1080/00167617808729036R. Bradshaw, D. Ingle Smith Permafrost Structures on Sully Island, Glamorgan, Geological Magazine 100, no.66 (May 2009): 556–564.https://doi.org/10.1017/S0016756800059100