Geology, Time and History

1989 ◽  
Vol 8 (2) ◽  
pp. 103-105
Author(s):  
Cecil Schneer
Keyword(s):  
18Th Century ◽  
Darwinian Evolution ◽  
Ice Age ◽  
Geological Time ◽  
Geologic Time ◽  
Rock Formations ◽  
Natural Time ◽  
Faunal Succession ◽  
Temporal Succession ◽  
Sense Of Time

There is evidence of consciousness of natural time as far back as the Early Ice Age in recorded observations of the recurrent and successive appearances of the moon. The idea of geologic time was broached as part of the 17th century scientific revolution in the same milieu as the ideal time of rational mechanics, but the sense of time drawn from observations of the earth transcended the limitations of ideal physical law. Inapplicable to "…an unlimited assemblage of local instabilities…" (Maxwell, 1877 p. 14), the laws of physics by definition are independent of the very particulars of time and place that are the essence of historical science. In the 18th century, Hutton formulated a physically dynamic theory of earth history as an indefinitely repeating series of cycles, while continental geologists such as Arduino and Werner constructed an ordinal classification of the major rock formations from primary crystalline basement to the alluvium of the present surface. The detailed scale of geological time as expressed in the geologic column was made possible by the discovery (principally by G. Cuvier and A.Brongniart and independently W. Smith) of the principle of faunal succession. By 1836, a consensus on the main outlines of the structure and biologic, as well as lithologic, succession was reached that held almost up to the present day. With temporal succession, the static scala naturae of Aristotle became first the progressionism of the great chain of being and finally, Darwinian evolution. The idea of geologic time encompasses all that we have learned of the history of our earth and its life.

scholarly journals Mapping glaciers in Jotunheimen, South-Norway, during the "Little Ice Age" maximum

2009 ◽  
Vol 3 (2) ◽  
pp. 231-243 ◽  
Author(s):  
S. Baumann ◽  
S. Winkler ◽  
L. M. Andreassen
Keyword(s):  
Little Ice Age ◽  
18Th Century ◽  
Field Measurements ◽  
Geographical Information ◽  
Ice Age ◽  
Inventory Data ◽  
Digital Elevation ◽  
Remote Sensing Techniques ◽  
Southern Norway ◽  
Elevation Model

Abstract. The maximum glacier extent during the "Little Ice Age" (mid 18th century AD) in Jotunheimen, southern Norway, was mapped using remote sensing techniques. Interpretation of existing glaciochronological studies, analysis of geomorphological maps, and own GPS-field measurements were applied for validation of the mapping. The length of glacier centrelines and other inventory data were determined using a Geographical Information System (GIS) and a Digital Elevation Model. "Little Ice Age" maximum extent for a total of 233 glaciers comprising an overall glacier area of about 290 km2 was mapped. Mean length of the centreline was calculated to 1.6 km. Until AD 2003, the area and length shrank by 35% and 34%, respectively, compared with the maximum "Little Ice Age" extent.

Holocene and latest Pleistocene fluctuations of Stutfield Glacier, Canadian Rockies

2001 ◽  
Vol 38 (8) ◽  
pp. 1141-1155 ◽  
Author(s):  
G D Osborn ◽  
B J Robinson ◽  
B H Luckman
Keyword(s):  
19Th Century ◽  
18Th Century ◽  
Late Glacial ◽  
Ice Age ◽  
Late 19Th Century ◽  
Canadian Rockies ◽  
The Holocene ◽  
The North ◽  
History Of ◽  
Glacier Advance

The Holocene and late glacial history of fluctuations of Stutfield Glacier are reconstructed using moraine stratigraphy, tephrochronology, and dendroglaciology. Stratigraphic sections in the lateral moraines contain tills from at least three glacier advances separated by volcanic tephras and paleosols. The oldest, pre-Mazama till is correlated with the Crowfoot Advance (dated elsewhere to be Younger Dryas equivalent). A Neoglacial till is found between the Mazama tephra and a paleosol developed on the Bridge River tephra. A log dating 2400 BP from the upper part of this till indicates that this glacier advance, correlated with the Peyto Advance, culminated shortly before deposition of the Bridge River tephra. Radiocarbon and tree-ring dates from overridden trees exposed in moraine sections indicate that the initial Cavell (Little Ice Age (LIA)) Advance overrode this paleosol and trees after A.D. 1271. Three subsequent phases of the Cavell Advance were dated by dendrochronology. The maximum glacier extent occurred in the mid-18th century, predating 1743 on the southern lateral, although ice still occupied and tilted a tree on the north lateral in 1758. Subsequent glacier advances occurred ca. 1800–1816 and in the late 19th century. The relative extent of the LIA advances at Stutfield differs from that of other major eastward flowing outlets of the Columbia Icefield, which have maxima in the mid–late 19th century. This is the first study from the Canadian Rockies to demonstrate that the large, morphologically simple, lateral moraines defining the LIA glacier limits are actually composite features, built up progressively (but discontinuously) over the Holocene and contain evidence of multiple Holocene- and Crowfoot-age glacier advances.

scholarly journals Climatic changes in the Urals over the past millennium – an analysis of geothermal and meteorological data

2007 ◽  
Vol 3 (2) ◽  
pp. 237-242 ◽  
Author(s):  
D. Yu. Demezhko ◽  
I. V. Golovanova
Keyword(s):  
20Th Century ◽  
18Th Century ◽  
Meteorological Data ◽  
Ground Surface ◽  
Ice Age ◽  
Temperature History ◽  
Joint Analysis ◽  
The Urals ◽  
The Past ◽  
Mean Temperature

Abstract. This investigation is based on a study of two paleoclimatic curves obtained in the Urals (51–59° N, 58–61° E): i) a ground surface temperature history (GSTH) reconstruction since 800 A.D. and ii) meteorological data for the last 170 years. Temperature anomalies measured in 49 boreholes were used for the GSTH reconstruction. It is shown that a traditional averaging of the histories leads to the lowest estimates of amplitude of past temperature fluctuations. The interval estimates method, accounting separately for the rock's thermal diffusivity variations and the influence of a number of non-climatic causes, was used to obtain the average GSTH. Joint analysis of GSTH and meteorological data bring us to the following conclusions. First, ground surface temperatures in the Medieval maximum during 1100–1200 were 0.4 K higher than the 20th century mean temperature (1900–1960). The Little Ice Age cooling was culminated in 1720 when surface mean temperature was 1.6 K below the 20th century mean temperature. Secondly, contemporary warming began approximately one century prior to the first instrumental measurements in the Urals. The rate of warming was +0.25 K/100 years in the 18th century, +1.15 K/100 years in the 19th and +0.75 K/100 years in the first 80 years of the 20th century. Finally, the mean rate of warming increased in the final decades of 20th century. An analysis of linear regression coefficients in running intervals of 21 and 31 years, shows that there were periods of warming with almost the same rates in the past, including the 19th century.

scholarly journals Nonlinear softening as a predictive precursor to climate tipping

2012 ◽  
Vol 370 (1962) ◽  
pp. 1205-1227 ◽  
Author(s):  
Jan Sieber ◽  
J. Michael T. Thompson
Keyword(s):  
Time Series ◽  
Basin Of Attraction ◽  
Stable State ◽  
Ice Age ◽  
Geological Time ◽  
Nonlinear Features ◽  
Last Ice Age ◽  
Earth’S Climate ◽  
Increasing Temperature ◽  
Linear Decay

Approaching a dangerous bifurcation, from which a dynamical system such as the Earth's climate will jump (tip) to a different state, the current stable state lies within a shrinking basin of attraction. Persistence of the state becomes increasingly precarious in the presence of noisy disturbances. We argue that one needs to extract information about the nonlinear features (a ‘softening’) of the underlying potential from the time series to judge the probability and timing of tipping. This analysis is the logical next step if one has detected a decrease of the linear decay rate. If there is no discernible trend in the linear analysis, nonlinear softening is even more important in showing the proximity to tipping. After extensive normal-form calibration studies, we check two geological time series from palaeo-climate tipping events for softening of the underlying well. For the ending of the last ice age, where we find no convincing linear precursor, we identify a statistically significant nonlinear softening towards increasing temperature.

scholarly journals Holocene and ‘Little Ice Age’ glacial activity in the Marboré Cirque, Monte Perdido Massif, Central Spanish Pyrenees

The Holocene ◽  
2014 ◽  
Vol 24 (11) ◽  
pp. 1439-1452 ◽  
Author(s):  
José M García-Ruiz ◽  
David Palacios ◽  
Nuria de Andrés ◽  
Blas L Valero-Garcés ◽  
Juan I López-Moreno ◽  
...  
Keyword(s):  
Little Ice Age ◽  
18Th Century ◽  
Sediment Cores ◽  
Rock Avalanche ◽  
Late Glacial ◽  
Maunder Minimum ◽  
Ice Age ◽  
Massif Central ◽  
Exposure Dating ◽  
Glacial Expansion

The Marboré Cirque, which is located in the southern Central Pyrenees on the north face of the Monte Perdido Peak (42°40′0″N; 0.5°0″W; 3355 m), contains a wide variety of Holocene glacial and periglacial deposits, and those from the ‘Little Ice Age’ (‘LIA’) are particularly well developed. Based on geomorphological mapping, cosmogenic exposure dating and previous studies of lacustrine sediment cores, the different deposits were dated and a sequence of geomorphological and paleoenvironmental events was established as follows: (1) The Marboré Cirque was at least partially deglaciated before 12.7 kyr BP. (2) Some ice masses are likely to have persisted in the Early Holocene, although their moraines were destroyed by the advance of glaciers during the Mid Holocene and ‘LIA’. (3) A glacial expansion occurred during the Mid Holocene (5.1 ± 0.1 kyr), represented by a large push moraine that enclosed a unique ice mass at the foot of the Monte Perdido Massif. (4) A melting phase occurred at approximately 3.4 ± 0.2 and 2.5 ± 0.1 kyr (Bronze/Iron Ages) after one of the most important glacial advances of the Neoglacial period. (5) Another glacial expansion occurred during the Dark Age Cold Period (1.4–1.2 kyr), followed by a melting period during the Medieval Climate Anomaly. (6) The ‘LIA’ represented a clear stage of glacial expansion within the Marboré Cirque. Two different pulses of glaciation were detected, separated by a short retraction. The first pulse occurred most likely during the late 17th century or early 18th century (Maunder Minimum), whereas the second occurred between 1790 and ad 1830 (Dalton Minimum). A strong deglaciation process has affected the Marboré Cirque glaciers since the middle of the 19th century. (7) A large rock avalanche occurred during the Mid Holocene, leaving a chaotic deposit that was previously considered to be a Late Glacial moraine.

Late Holocene glacial activity in Manatee Valley, southern Coast Mountains, British Columbia, Canada

2011 ◽  
Vol 48 (3) ◽  
pp. 603-618 ◽  
Author(s):  
Lindsey Koehler ◽  
Dan J. Smith
Keyword(s):  
British Columbia ◽  
Late Holocene ◽  
18Th Century ◽  
Ice Age ◽  
Coast Mountains ◽  
Mountain Glaciers ◽  
Subsequent Episode ◽  
Glacial Expansion ◽  
Insight Into ◽  
Lichen Growth

The dendroglaciologic and lichenometric research methodologies employed in this study provide a perspective of glaciological conditions from 5 ka to present in a remote headwater area of the British Columbia Coast Mountains. Since Holocene ice fronts of four glaciers at this site periodically extended below treeline, previous glacier advances overrode and buried forests beneath till deposits. This study suggests that glaciers were expanding into standing forests at 4.76 and 3.78 ka. Following glacier expansion at 3.78 ka, a period of recession ensued when glaciers withdrew upvalley long enough for the development of deep pedogenic surfaces and the growth of trees exceeding 300 years. Investigations at Beluga and Manatee glaciers benchmark a subsequent episode of significant glacial expansion at 2.42 ka referred to as the “Manatee Advance”. This advance has regional correlatives and is distinguished from the Tiedemann Advance at Manatee Glacier by documentation of substantive ice front retreat between the two episodes. Examination of Little Ice Age (LIA) deposits in the study area allowed for presentation and application of a revised Rhizocarpon spp. lichen growth curve. Lichenometric surveys of lateral moraines associated with Beluga, Manatee, and Oluk glaciers provided limited insight into their early LIA behaviour but record advances during the 15th and 16th centuries. Locally, glaciers achieved their maximum LIA size prior to an early to mid 18th century moraine-building event. This reconstruction of Holocene glacial history offers insights consistent with the emerging record of glacier activity described for other southern British Columbia Coast Mountain glaciers.

The Correlation Between Impact Crater Ages and Chronostratigraphic Boundary Dates

2020 ◽  
Author(s):  
R B Firestone
Keyword(s):  
Weighted Least Squares ◽  
Continuous Process ◽  
Ice Age ◽  
Multiple Impacts ◽  
Geological Time ◽  
Geological Time Scale ◽  
Least Squares Fit ◽  
Highly Correlated ◽  
The Times ◽  
The Impact

Abstract The accurately measured ages of 89 large impact craters and layers were compared with the boundary dates for Periods, Epochs and Ages of the Geological Time Scale by a weighted least squares fit. They are highly correlated with a χ2/f=0.63. A Monte Carlo simulation of randomly chosen crater ages gives a >99.8% probability that this result is not random. No craters are found in the oceans or, until recently, in ice which collectively cover 80% of Earth’s surface indicating that far more impacts have occurred than are known. Multiple impacts cluster near the times of boundary dates so, based on the observed cluster sizes assuming a binomial distribution, it was determined that the average cluster multiplicity is five. Comparison of the impact ages with the dates of the great extinctions revealed a strong correlation with χ2/f=0.36 and a multiplicity of 8-9 impacts. It is shown that volcanism, although correlated with boundary dates, is a continuous process unrelated to sudden extinctions. During the past 125 Ma the rate of global change and the impact rate have increased dramatically as the Earth passes near the OB star association. Multiple impacts 12.9 ka ago ended the Pleistocene epoch at the onset of the Younger Dryas (YD) causing worldwide extinctions. The date and extent of the YD impact may be consistent with a 62 Ma cycle of major impact events. During the Holocene 20 crater, airburst, and impact tsunami chevron ages correspond to dates of global cooling with a χ2/f=0.75 and >99% probability. Future impacts could reverse global warming or even induce next ice age.

Little Ice Age subsidence and post Little Ice Age uplift at Juneau, Alaska, inferred from dendrochronology and geomorphology

2003 ◽  
Vol 59 (3) ◽  
pp. 300-309 ◽  
Author(s):  
Roman J. Motyka
Keyword(s):  
Sea Level ◽  
Little Ice Age ◽  
18Th Century ◽  
Tide Gauge ◽  
Ice Age ◽  
Tide Gauge Records ◽  
Relative Sea Level ◽  
Late 18Th Century ◽  
Glaciomarine Sediments ◽  
Sea Cliff

AbstractApplication of dendrochronology and geomorphology to a recently emerged coastal area near Juneau, Alaska, has documented a Little Ice Age (LIA) sea-level transgression to 6.2 m above current sea level. The rise in relative sea level is attributed to regional subsidence and appears to have stabilized by the mid 16th century, based on a sea-cliff eroded into late-Pleistocene glaciomarine sediments. Land began emerging between A.D. 1770 and 1790, coincident with retreat of regional glaciers from their LIA maximums. This emergence has continued since then, paralleling regional glacier retreat. Total Juneau uplift since the late 18th century is estimated to be 3.2 m. The rate of downward colonization of newly emergent coastline by Sitka spruce during the 20th century closely parallels the rate of sea-level fall documented by analysis of local tide-gauge records (1.3 cm/yr). Regional and Glacier Bay LIA loading and unloading are inferred to be the primary mechanisms driving subsidence and uplift in the Juneau area. Climate change rather then regional tectonics has forced relative sea-level change over the last several hundred years.

scholarly journals Glacier Recession and Lake Shrinkage Indicating a Climatic Warming and Drying Trend in Central Asia

1990 ◽  
Vol 14 ◽  
pp. 261-265 ◽  
Author(s):  
Shi Yafeng ◽  
Ren Jiawen
Keyword(s):  
18Th Century ◽  
Ice Age ◽  
Tibet Plateau ◽  
Qinghai Lake ◽  
Climatic Warming ◽  
Glacier Recession ◽  
Drying Trend ◽  
Early And Middle Holocene ◽  
Near Future ◽  
Large Deficit

Mass balance observations on Urumqi River No. 1 Glacier and Tuyuksu Glacier in Tianshan show a large deficit during the 1980s as compared to the decades before. The Qinghai Lake in northeastern Qinghai-Xizang (Tibet) Plateau and the Issyk-kul Lake in Soviet Tianshan have been continuously shrinking during the past few centuries. Since the maximum of the Little Ice Age which occurred mainly in the 18th century, glaciers have decreased in area by about 44% in the Urumqi valley. These data and other evidence from glaciers, lakes, etc. clearly indicate that the climatic warming and drying tendency grows stronger in this century and will possibly persist to the early decades of the next century. The growing greenhouse effect due to the increase of CO2 and other related gases will enhance this tendency in the near future. However, should the high temperature period of the early and middle Holocene reappear, the climate would become humid.

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