Quaternary period

Numerous theories exist as to how the Chilean deposits formed and survived. It has been postulated that the unique nitrate-rich caUche deposits of northern Chile owe their existence to an environment favorable to accumulation and preservation of the deposits, rather than to any unusual source of the saline materials (2). The essential conditions are an extremely arid climate similar to that of the Atacama desert in the 1990s, slow accumulation during the late Tertiary and Quaternary periods, and a paucity of nitrate-utilizing plants and soil microorganisms. 

Hulten, E. 1937. Outline of the history of arctic on boreal biota during the quaternary period. 

Fig. 3.1. Histogram showing the change in volume of volcanic products during the Neogene and Quaternary periods. The far-right part shows a very small amount for the Paleogene Period (Sugimura et al., 1963).

Meltzer, D.J. (2004). Peopling of North America. In The Quaternary Period in the United States, ed. Gillespie, A.R., Porter, S.C. and Atwater, B.F., Developments in Quaternary Science 1, Elsevier, Amsterdam, pp. 539-563. 

From the Devonian to the Quaternary period, the study area experienced a complicated geological and weathering history (Fig. 4). Granodiorite or biotite adamellite granite intmded Devonian tuff... 

The Quaternary Period is subdivided into the Pleistocene Epoch and, commencing at 10,000 years ago, the Holocene Epoch. The Holocene is synonymous with the Postglacial or present interglaciation. ... 

Period (geological) A commonly used division of geologic time. Eras are divided into periods. The Quaternary period extends from 1.75 million years ago to the present. 

Conway (1942) and Smulikowski (1954) have interpreted the potassium-distribution data to indicate that there is a potassium deficiency in Tertiary and Recent seas. However, Spiro and Gramberg (1964) made analyses of the composition of cations adsorbed on argillaceous rocks of northern Siberia and concluded that ... the highest content of potassium is inherent in marine water of the Permian Period. In Triassic seas the content of the potassium dropped significantly, and reached a minimum in seas of the Jurassic Period. Beginning with Cretaceous, the amount of potassium in sea water increased again, and during the Quaternary Period its level approached that of the Permian seas. These ideas are extremely speculative. 

Structural estuaries are formed by neotectonic (within the Quaternary period or past 1.8 My BP) processes such as faulting, volcanism, postglacial rebound, and isostacy that have occurred since the Pleistocene. 

During the subsequent Miocene-Pliocene and Quaternary periods, the thickness of the sediments increased. 

Pleistocene The first geologic epoch of the Quaternary Period of the Cenozoic Era that ended 10,000 years ago with the retreat of the last glaciers. 

Quaternary Period The most recent geologic period of the Cenozoic Era, the Quaternary began 2 million years ago with the growth of northern hemisphere continental glaciers and the ice age. 

Hokr, A., 1951. A method of the quantitative determination of the climate in the Quaternary Period by means of mammal associations. Sbornik. Geol. Ust. Csl., 18 (Paleont.) 209-219. 

We have emphasized in Section 8.09.3 that the carbon-cycle variations observed on glacial/ interglacial time scales during the Quaternary period can be understood in terms of the redistribution of carbon among the atmosphere, oceans, biosphere, and reactive sediments. Over timescales of millions of years and longer, many... 

Winograd, I. J., and Szabo, B. J., 1988, Water-table decline in the south-central Great Basin during the Quaternary period—implications for toxic waste disposal, in Geologic and Hydro-logic Investigations of a Potential Nuclear Waste Disposal Site at Yucca Mountain, U.S. Geol. Surv. Bulletin 1790, pp. 147-152. 

The Cenozoic Era (c.65 million years BP to the present) encompasses the Tertiary and the Quaternary Periods. During the Tertiary the Earth s climate began an overall cooling trend of about 12 °C in the past 40 million years. Over the past two and a half million years the climate has varied from cool to warm periods, accompanied by massive expansions and contractions of the polar ice caps. This period of climate fluctuation is termed the Quaternary Period and spans the geologic time scale from the end of the Pliocene Epoch, roughly 1.8-2.6 million years ago, to the present. The Quaternary Period includes the Pleistocene and Holocene Epochs, with the Holocene... 

Holocene. An epoch of the Quaternary period of the geologic time scale from the end of the Pleistocene to the present commenced approximately 10,000 years ago. 

The Paratoon thermal water field is located within the Central Kamchatka volcanic area, 25 km apart from Petropavlovsk-Kamchatski. The field is confined to the structural depression of the Paratoonka river valley, which is a graben of complicated structure formed by block-wise shifts of crystalline foundation in quaternary period. 

Table 13.2 Glacial evolution of northern Europe during the past 1.6 million years, the Quaternary period...

The most recent epoch of the Quaternary period, covering approximately the last 10,000 years, humus... 

The earlier of the two epochs of the Quaternary period, starting 2 to 3 million years before the present and ending about 10,000 years ago. It was a time of glacial activity, positive feedback... 

Holocene (Recent) 1) Time The last epoch within the Quaternary Period and the Ceno-zoic Era, equivalent to Oxygen Isotope Stage 2. Traditionally defined to have begun at 10 ka, some now place the boundary at approximately 10.8 ka, at the end of the Younger Dryas event. 2) Rocks The rocks or sediment formed during the Holocene Epoch, also known as the Flandrian in Britain. 

Quaternary 1) Time The second and last period in the Cenozoic Era. Normally, it is subdivided into the Holocene (Recent) and Pleistocene Epochs. The short chronology places its beginning at the traditionally defined boundary atroughly 1.78 Ma, while the long chronology places it at the start of the Matuyama Magnetochron at approximately 2.48 Ma. 2) Rocks The sediment and rocks formed during the Quaternary Period. 

Loess is a special kind of wind-blown deposit under arid-semiarid environment in Quaternary period. Its physical and mechanical properties are related to the forming environment. The stratum and physical properties are general identical under a definite environment, therefore the study for a particular case can provide reference in the area of same deposit unit. 

The conclusions of these authors on the importance of climate are undoubtedly very valid but soil type (mesotrophic vs. dystrophic) can also be the major factor in determining the floristics and structure of cerrado communities (Ratter et al, 1977 Furley and Ratter, 1988 Ratter and Dargie, 1992). It should also be remembered that in addition to present-day enviromnental factors the vegetation pattern of the Cerrado Biome must reflect the major dynamic changes which are known to have occurred repeatedly during the Quaternary period, and much further research is necessary to correlate observations with new data emerging on this subject. 

The Cerrado Biome covers an area of 2,000,000 km, from 3°N to 24°S, extending from the Amazon basin, in the north, to Sao Paulo (SP) and Parana states, in the south, with an altitudinal range from sea level to 1800 m (Ratter et al., 1997). It has been subject to many changes over the Quaternary period and it is relevant to consider these since they are still in progress and particularly important... 

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