Great Glaciation Research Articles

Formation of Crystalline Silica–Carbonate Biomorphs of Alkaline Earth Metals (Ca, Ba, Sr) from Ambient to Low Temperatures: Chemical Implications during the Primitive Earth’s Life

The Earth has undergone at least four great glaciations, during which the ice layers and the glaciers have expanded all over the planet, corresponding to significant drops in global temperatures th...

On the early evolutionary stage of the geosphere and biosphere and the problem of early glaciations

The early evolutionary stages of the geosphere and biosphere are determined by three interrelated factors: (1) continuous cooling of the surface and interior (mantle) of the Earth (the mean temperatures of the mantle and surface decreased by a factor of 1.5–2 and 3–4, respectively; the mean heat flow was reduced by approximately one order of magnitude, and viscosity, by three orders); (2) continuous stepwise oxidation of the surface, which was particularly well pronounced from 3.8 to 1.8 Ga; and (3) periodic and correlated fluctuations of conditions in the geosphere and biosphere of varying extent and nature. The major boundaries of this evolution were about 4 Ga (the origin of rather thick and heterogeneous earth’s crust, the origin of life); about 3 Ga (appearance of a strong magnetic field, an increase in photosynthetic activity); about 1.8–1.9 Ga (appearance of an oxidized atmosphere, the first supercontinent, possibly, the first superplumes from the nucleus); and about 0.75 Ga (acceleration of subduction, “watering” of the upper mantle, elevation of continents with vast land masses, shelves, large rivers, and the first great glaciations). The significance and correlations of the earliest events (before and about 4 Ga) and events about 750 Ma are widely debated. In the Late Archean and Early Proterozoic (before 1.8 Ga), the biosphere was dominated by cyanobacteria, the dynamics and developmental peaks of which are marked by the presence of widespread stromatolite buildups in carbonaceous rocks (initially, mostly dolomitic matter). About 700–750 Ma, intense and frequent glaciations developed, marking the cooling of the Earth. The greatest glaciation apparently occurred about 640 Ma, which gave rise to the discussion of the model of the Snowball Earth. The emergence and evolution of skeletons in animals is sometimes thought to be connected with glaciations. These events are correlated and accounted for by great endogenous changes. One of the major events in endogenous history is the onset about 750 Ma of periodic manifestation of mantle flows (superplumes), which explain further periodicity of the biosphere evolution. In conclusion, extrapolation of future evolution and successive collapse of biosphere segments in the course of transformation of the Sun into a red star and warming of the Earth surface are proposed.

A comparison of the biological, geological events and environmental backgrounds between the Neoproterozoic-Cambrian and Permian-Triassic transitions

The Neoproterozoic-Cambrian (N-C) and Permian-Triassic (P-T) transitions have been regarded the two most critical transitions in earth history because of the explosive biological radiation in the early Cambrian (the Cambrian Explosion) and the largest mass extinction at the end-Permian. Previous studies suggest that these two critical transitions showed certain comparability in major evolutionary events. In other words, a series of biological, geological, and geochemical events that had happened in the N-C transition occurred repeatedly during the P-T transition. Those events included continental re-configuration related to the deep mantle dynamics, global-scale glaciations, large C-, Sr-, and S-isotope perturbations indicating atmospheric and oceanic changes, abnormal precipitation of carbonates, and associated multiple biological radiations and mass extinctions. The coupling of those events in both N-C and P-T transitions suggests that deep mantle dynamics could be a primary mechanism driving dramatic changes of environment on the earth’s surface, which in turn caused major biological re-organizations. A detailed comparison of those events during the two critical transitions indicates that despite their general comparability, significant differences do exist in magnitude, duration, and frequency. The supercontinent Rodinia began to rift before the Snowball Earth time. By contrast, the supercontinent Pangea entered the dispersal stage after the greatest glaciation from the Late Carboniferous to Cisuralian. Quantitative data and qualitative analyses of different fossil groups show a more profound mass extinction during the N-C transition than at the end-Permian in terms of ecosystem disruption. This is indicated by the disappearance of the whole Ediacaran biota at the N-C boundary. The subsequent appearances of many new complex animals at phylum level in the early Cambrian mark the establishment of a brand new ecosystem. However, the end-Permian mass extinction is manifested mainly by the extinction of many different taxa at class and order levels. Although it caused the extinction of 95% of marine species and 75% of terrestrial species as well as complete cessation of coal and reef deposits after the mass extinction, this high-level biological re-organization still occurred within an established ecosystem, however drastic it may seem. Survived or Lazarus taxa re-occupied the existing ecospace in a relatively short duration after the end-Permian mass extinction. C-isotope excursions display large perturbations during both transitions, yet also in different magnitudes and frequencies, which suggest different atmospheric and oceanic conditions. The recurrent geological and geochemical events as well as the coupled major biological turnovers during the two transitions provide new clues to understanding the interplays among the earth-life system. Thus, it is essential to carry out multidisciplinary studies from the deep internal system to the surface of the Earth as a whole in order to unravel the interactions of different spheres of the earth.

The Baykonurian glaciohorizon of the Late Vendian

Glacial deposits occurring close to the Vendian-Cambrian boundary were discovered long ago in several regions of Asia and West Africa. New data of recent years confirm earlier observation and specify age constraints of these deposits. In certain sections, glacial sediments rest on beds with the Upper Vendian fossils (Vendotaenia sp., Sabellidites remains, and microfossils). In the Hoggar Highland, they discordantly overlie magmatic rocks ca. 560 Ma old. In the East Sayan Mts., the Upper Vendian Cloudina sp. have been found in the diamictite matrix. In Central Asia and Northwest China, cap dolomites conformably overlying glacial deposits grade upward into the chert-phosphatic sediments containing fossils (Tarim region), which are characteristic of the Anabarites trisulcatus Zone in the Nemakit-Daldynian Stage. Fossils of this zone have been found directly above glacial deposits in the East Sayan. According to all these data, the respective Baykonurian glaciation, as it is termed in this work, either antedated the Nemakit-Daldynian Age or was concurrent to its commencement. The glaciation is correlative with a significant negative δ13C excursion of −5 to −10‰. Judging from recent paleotectonic reconstructions, the Baykonurian glaciation was not regional in rank and left records in both hemispheres of the Earth. This glaciation resumes the well-known succession of the great glaciation event in the terminal Late Precambrian, i.e., the Sturtian, Marinoan, and Gaskiers glaciations. Hence, one cannot ignore the Baykonurian glaciation when analyzing the geological, biospheric, and biotic history of the Late Precambrian.

How to Cope with Climate’s Complexity?

Climate exhibits a vast range of dissipative structures. Some have characteristic times of a few days; others evolve over thousands of years. All these structures are interdependent; in other words, they communicate. It is often considered that the only way to cope with climate complexity is to integrate the equations of atmospheric and oceanic motion with the finest possible mesh. Is this the sole strategy? Aren’t we missing another characteristic of the climate system: its ability to destroy and generate information at the macroscopic scale? Paleoclimatologists consider that much of this information is present in palaeoclimate archives. It is therefore natural to build climate models such as to get the most of these archives. The strategy proposed here is based on Bayesian statistics and low-order non-linear dynamical systems, in a modelling approach that explicitly includes the effects of uncertainties. Its practical interest is illustrated through the problem of the timing of the next great glaciation. Is glacial inception overdue or do we need to wait for another 50,000 years before ice caps grow again? Our results indicate a glaciation inception in 50,000 years.

Eolian evidence from the Chinese Loess Plateau: the onset of the Late Cenozoic Great Glaciation in the Northern Hemisphere and Qinghai-Xizang Plateau uplift forcing

On the basis of a newly-constructed record of magnetic susceptibility (SUS) and the depositional rate change of eolian loess-red clay sequences in the last 7.2 Ma BP from the hea Plateau, together with a cornperison of a record of °18O values from the equatorial East Pacific Ocean and eolian Quartz flux variations fmm the North Pacific Ocean, the evolutiomuy process of the Late Cenozoic Great Glaciation in the Northern Hemisphere can be divided into three stages: the arrival stage around 7.2–3.4 Ma BP, the initial stage at about 3.4—2.6 Ma BP, and the Great Ice Age since 2.6 Ma BP. The evolution of the East Asian monsoon is characterized by paid winter and summer monsoons, and it is basically composed of the initial stage of weak winter and summer monsoons, the transitional stage of simultaneous increase in intensity of winter and summer monsoons, and the prevailing stage of strong winter and week summer monsoons, or weak winter and strong summer monsoons. The Late Cenowic global tectonic uplift, paaicdarly the Qinghai-Xizang Plateau uplift and the associated CO2 concentration variation, controls the dng processes of the onset of Great Glaciation and the long-term changes of East Asian monsoom climate in the Northern Hemisphere to a large extent. The accelerating uplift of the Qinghai-Xizang Plateau between 3.4 and 2.6 Ma BP provided an important driving force to global climiatic change.

Investigation into albedo-controlled energy loss during the last glaciation

In recent years, attention has increasingly been paid to the question of the stability of the earth's climate. It has been observed that changes in climate are usually related to changes in the earth's surface. On this question, Liedtke writes ‘A change in climate can lead to considerable landscape changes’ (Liedtke 1990, p. 38). There seems to be some form of interaction between climate and the condition of the earth's surface. If solar radiation is taken to be the primary energy source for the earth's climate, the question arises as to how insolation affects the character of the earth's surface, and vice versa, how does the character of the earth's surface affect the insolation which occurs? Reconstructions of the last great Pleistocene glaciation 18,000 years ago show that the form of the earth's surface at that time was considerably different to its present form. In view of the interaction mentioned above between climate and earth surface, does this suggest a difference between the earth's radiation budget 18,000 years ago and that of today? If, as is widely believed, the area of the earth's surface covered by ice 18,000 years ago was approximately three times the current area (Liedtke 1990, p. 42), this presumably would have had at least some influence on the earth's radiation budget. The ice-covered areas may have modified the radiation budget by means of their high reflexivity. In other words, an albedo-related loss of radiation may have occurred. The results of this investigations show, that the global radiation budget at 18,000 B.P was about 7- -10% less than that of today.

Influence of tectonics on the extent of quaternary glaciation in the Andes

The extent of Quaternary glaciations varies throughout the Andes. Although the lack of radiometric dating in many places precludes precise assessment of these variations, certain spatial patterns are evident. In the N. Andes (N. of 15ºS) glacial landforms and sediments of only the ultimate and penultimate glaciations (O-isotope stages 2, 4, 6) have been identified. In the Central Andes (15-35ºS) successive glaciations since at least the mid-Quaternary have been progressively less extensive. In the Southern Andes successive glaciations since the greatest glaciation at ca. 1.2 Ma have been progressively smaller; also, the Islas Malvinas 800-1,000 km to the east became glaciated for the first time during the penultimate glaciation and developed an even greater number of nivo-glacial features during the last glaciation. The segmented nature of the oceanic and continental crust along the Pacific-South American subduction zone promotes tectonic independence of parts of the Andean chain. It is argued that variations in the extent of glaciation may be largely explained by Quaternary uplift and subsidence in different places and by precipitation-shadow effects related to elevation and air mass source.

Comparative study of three drumlin fields in western Ireland: geomorphological data and genetic implications

The three drumlin fields of the Killala-Ballina (1519 drumlins studied), Clew Bay (320 drumlins studied) and Castlebar (385 drumlins studied) areas were formed within the marginal areas of the Upper Pleistocene Great Glaciation of Ireland. Each field has been mapped (drumlin location, density, elongation, cumulative surface and weighted orientation) to understand the relation of their drumlin assemblages and internal drumlin variations with the local and regional topography and lithology. Concerning the drumlinization, comparative study of the three fields emphasizes the part played by geomorphic and lithological control upon the motion, orientation and dynamics of a thin ice cover and suggests that the streamlined material may be sometimes reworked from older glaciation deposits.

Problems of Quaternary geology and palaeoecology of North European seas

The Quaternary geology in the recent 25 years has been characterized by an intense accumulation of data and by the development of a number of hypotheses on the history and evolution of the Barents Sea (Boulton 1979; Elverhdi & Solheim 1983; Vorren & Kristoffersen 1986). The main feature of the climate transformation in the Cenozoic era was the great continental glaciation and the oceanic penglacial area (Matishov 1984, 1987).

Nature et distribution des dépôts glaciaires et périglaciaires en Irlande occidentale : discussion sur l'extension de ta dernière grande glaciation

Definition and distribution of the glacial and periglacial deposits in Western Ireland : discussion about the extent of the last great glaciation. In the Upper Pleistocene, Western Ireland was invaded by the Midlandian ice-sheet, except nunataks-mountains occupied by a contemporary local glaciation. A large assemblage of pleniglacial, cataglacial and end-glacial deposits is inherited from all these mountainous and regional ices. The periglacial processes occurred only on the high slopes of nunataks and in the early deglaciated lowlands. In the late Tardiglacial, some comes were filled by a little mountain glaciation. The periglacial events were more extended but with a few intensity. During these cold periods, the retaining of the atlantic climate influences is proved by the varied glacial mountainous and regional periglacial heritages. In other respects, the re-examination of genetic and chronological datas of numerous lowland deposits shows that the last Great Glaciation was extended on all the western country : the probability of « unglaciated areas » (with severe periglacial inherited datas) is so very weak. Generally speaking, it seems necessary to re-examine the definition and extent criteria (originally palaeobotanical) of such « unglaciated areas » in other parts of Ireland.

Multiple glaciations of the Cordon del Plata, Mendoza, Argentina

Evidence exists for four glaciations in the Río Blanco basin west of Mendoza, Argentina. Morphology, superposition of tills, soil-profile development, loess thickness, and boulder weathering have been the techniques most useful in mapping the tills. Glaciers of Vallecitos (= Wisconsinan) age extended to 2600 m and left distinctive moraines. Tills of two pre-Vallecitos glacier advances cover the floor of the valley from 2600 m to below 2100 m, and remnants of one of the tills extend nearly to the junction with Río Mendoza (1400 m) 13 km below the lowest Vallecitos moraines. These deposits were considered to be mudflows rather than tills by Polanski; however, the quartz sand grains examined with SEM have surface textures characteristic of glacial abrasion. The sediments, thus, are more likely glacial than mudflow deposits. One still older till caps ridges as much as 200 m above the present valley floor. Vallecitos glaciers did not smooth the walls of the wide valleys through which they flowed; the valleys had been enlarged by the larger ice tongues during one or more of the earlier glaciations. Frost shattering of the rhyolite and quartzite has altered much of the distinctive glacial valley shape, and talus lies between valley walls and Vallecitos lateral moraines. Holocene glaciations seem to be in phase with those of the Northern Hemisphere, and the Vallecitos glaciation coincided with oxygen isotope stage 2 and the Wisconsin of North America. The next older glaciation may correlate with oxygen isotope stage 6 and the Illinoian glaciation of North America. A till that underlies it is difficult to correlate and is clearly much older, but postdates the last major uplift of the range. It may represent isotope stage 12, and the period that followed it was more moist than other interglacial ages in this area. The oldest, Los Mesones, may correlate with Mercer's “Greatest Glaciation” of Patagonia, 1.0 to 1.2 m.y. ago. Although it is beyond the established oxygen isotope stages, a long cold period is present on the curves at this time, nd it coincides with one of the glaciations of the “Nebraskan—Kansan” complex of North America.

Relationship of glaciations and rapid changes in organic life to events in outer space

On the basis of a synthesis of new data from geology, astrophysics, and radiation genetics, this article considers the relationship of the great glaciations to stages of rapid mass extinctions and the synchronous or subsequent flourishing of other groups of organisms. It is shown that the glacations could not have resulted from terrestrial causes, but rather were related to diminutions of solar radiation. The biological revolutions were due to quasi-periodic Increases of intensity of ionizing cosmic radiation, which caused sharp accelerations of the mutation rates. These increases in cosmic radiation were most likely caused by explosions of supernovae in the vicinity of the solar system. The gas and dust cloud thus created screened the solar radiation, thereby diminishing the temperature at this planet's surface. This article also considers the results of the selective action of cosmic radiation on the various groups of organisms during the biological revolutions, as well as the possible reasons for the q...

Quaternary Glaciation of the Waterton - Castle River Region of Alberta

ABSTRACT The Waterton - Castle River Region includes the extreme limits of advance of both Cordilleran glaciers flowing from the Rocky Mountains eastward toward the plains, and massive Laurentide glaciers advancing upslope from the plains and the Canadian Shield toward the mountains. Its glacial record, which spans about the last third of the Quaternary Period, can be divided into four events. Each consists of a Cordilleran glacier and a corresponding Laurentide one, though during the last event Laurentide ice failed to reach the region. The record also includes the late neoglaciation found near the heads of mountain valleys. Undoubtedly, many Pleistocene glaciers are not represented in the record, because their deposits have been destroyed by later ones. Although this fact may explain the apparent absence of pre-Illinoian Cordilleran glaciers, pre-Illinoian Laurentide glaciers definitely did not reach the region. The glaciations of the region show a steady decrease in intensity and strength. The first, of Illinoian age, is here called the Great Glaciation, and its glaciers the Great Cordilleran and Great Laurentide glaciers. These were immense glaciers, far surpassing in magnitude any others before or after. The Great Cordilleran Glacier left drift in the preglacial valleys far out onto the plains, and on high areas in the foothills such as Mokowan Butte and Cloudy Ridge just east and north of Waterton Park respectively. During this time the park lay under a great ice-dome, with only its highest peaks possibly protruding. The Great Laurentide glacier dropped Shield stones high on the mountain front and spread till over the mountain drift in the preglacial valleys. Later, during Wisconsin time, Cordilleran glaciers were confined to valleys in the mountains and spread only a short distance onto the plains. Laurentide glaciers likewise were much reduced in size. The first was about 800 ft (240 m) lower than the Great Laurentide Glacier, the following one another 1,000 ft (300 m) lower, and the next one 600 ft (180 m) lower again. All the Cordilleran glaciers of the region had undergone substantial retreat before Laurentide glaciers arrived on the scene, and the amount of contact between the two types is not known. It possibly was substantial during the Great Glaciation, but none or very little during the next. During succeeding glaciations the Cordilleran and Laurentide glaciers did not meet within the region.

Problems of the Emergence of Human Society and the Archeological Discoveries of the Past Decade

The study of primitive times in the past few decades has shown many seemingly effective and persuasive models and constructs being smashed and discarded. Some 40 years ago scholars found logical and indisputable the postulate that the earliest apelike men of the Chellean and Acheulean phases only gathered vegetable food and caught small animals and knew nothing about either fire or life in caves! Whereupon (so the scenario went) the great glaciation set in, and the Neanderthals switched to hunting large animals, settled in caves, and mastered fire.

Problems of the Emergence of Human Society and the Archeological Discoveries of the Past Decade

The study of primitive times in the past few decades has shown many seemingly effective and persuasive models and constructs being smashed and discarded. Some 40 years ago scholars found logical and indisputable the postulate that the earliest apelike men of the Chellean and Acheulean phases only gathered vegetable food and caught small animals and knew nothing about either fire or life in caves! Whereupon (so the scenario went) the great glaciation set in, and the Neanderthals switched to hunting large animals, settled in caves, and mastered fire.

Great glaciations in history of the earth

Great glaciations in history of the earth

Carboniferous Glaciation in Gondwanaland

Refutes interpretations by M. M. Anderson of earlier statements on early Carboniferous glaciation in Ghana and northern Brazil and reiterates the conclusion that it would have been only peripheral to the great glaciation in Gondwanaland.

Nouvelles donnees sur les alluvions du plateau de Vassincourt (Meuse)

Abstract The alluvial deposits of the Vassincourt plateau, France, consist of fluviatile gravels overlain by unstratified clays. The basal gravels contain a typical cold climate (tundra) fauna, which was undoubtedly contemporaneous with the great glaciation of northern Europe. The upper fluviatile deposits contain a mixed fauna and were deposited during a long interglacial period. A new glacial phase, rainy at first, produced the clays, which are both alluvial and eluvial. Subsequent uplift and erosion account for the present topography.

Post-Glacial Prehistory in Ireland

OUR knowledge of the post-glacial prehistory of northern Ireland is summarised by Mr. C. Blake Whelan in a recent communication to the Société Préhistorique francaise (Bull. 1931, 7.8). Although Chellean and Acheulean do not appear, it is possible to find in the gravels of north-east Ireland rare and doubtful specimens which appear to be humanly worked and may be examples of a pre-Mousterian, or even older, culture. The interesting Clactonian station of Rosses Point, Sligo, is an example. Yet up to the present, undoubted evidence of a true Mousterian of the Laufen interval between Wiirm I. and II. appears to be lacking. Man may have retreated southward and not returned until the great glaciations had definitely retreated from Ireland.