The Quaternary history of Fuego-Patagonia

1960 ◽  
Vol 152 (949) ◽  
pp. 507-516 ◽  
Keyword(s):  
Tierra Del Fuego ◽  
Ice Age ◽  
Ice Ages ◽  
The Andes ◽  
Plant Remains ◽  
Westerly Winds ◽  
History Of ◽  
Last Ice Age ◽  
Quaternary History ◽  
Important Evidence

Tierra del Fuego and Patagonia are geographically so closely related that they can he called Fuego-Patagonia. Its two main units are the Andes and the region of the mesetas to the east of them. As a result of the predominantly westerly winds, the rainfall and the forests are concentrated in the Andes whereas in the region of the mesetas and the plains there are steppes and semideserts. The boundary between them seems to be a zone of struggle between the forest and the steppe. Its past oscillations can be studied against the background of palaeogeographic evolution especially since the last ice age. The stratigraphy of bogs and alluvial clays provides most important evidence on this topic. Tierra del Fuego is especially suitable as a study area since bogs are present all over the main island. In order to separate the ice ages with certainty, and thus to find out how many ice ages there were in Fuego-Patagonia, I looked for organic interglacial layers. Those found are the only ones so far recorded in South America. The southernmost is on the east coast of Tierra del Fuego in a till cliff facing the Atlantic Ocean, about 20 km from the Viamonte estancia (figure 26). The peat is, according to a dating at the Yale Geochronometric Laboratory, over 41000 years old. Its macro- and microscopic plant remains reflect a richer flora than the present one.

scholarly journals The rise and fall of the Refugial Hypothesis of Amazonian speciation: a paleoecological perspective

2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Mark B. Bush ◽  
Paulo E. de Oliveira
Keyword(s):  
Amazon Basin ◽  
Late Quaternary ◽  
Indirect Evidence ◽  
Ice Age ◽  
Data Set ◽  
The Andes ◽  
History Of ◽  
Last Ice Age ◽  
Northern Hemispheric ◽  
Amazonian Forests

The refugial hypothesis is treated as the definitive history of Amazonian forests in many texts. Surprisingly, this important theoretical framework has not been based on paleoecological data. Consequently, a model of Amazonian aridity during the northern hemispheric glaciation has been accepted uncritically. Ironically, the Refuge Hypothesis has not been tested by paleobotanical data. We present a revision of the concept of Neotropical Pleistocene Forest Refuges and test it in the light of paleocological studies derived from pollen analysis of Amazonian lake sediments deposited during the last 20,000 years. Our analysis is based primarily on paleoenvironmental data obtained from sites in Brazil and Ecuador. These data are contrasted with those that favor the hypothesis of fragmented tropical forests in a landscape dominated mainly by tropical savannas under an arid climate. The Ecuadorian data set strongly suggests a 5ºC cooling and presence of humid forests at the foot of the Andes, during the last Ice Age. The same climatic and vegetational scenario was found in the western Brazilian Amazon. On the other hand, somewhat drier conditions were observed in the central Amazon, but the landscape remained a forested landscape during the supposedly arid phases of the Late Quaternary. Data obtained from the Amazon Fan sediments containing pollen derived from extensive sections of the Amazon Basin, were fundamental to the conclusion that the predominance of savannas in this region is not supported by botanical data. Our revision of the assumptions derived from the Refuge Hypothesis indicates that it has succumbed to the test now permitted by a larger paleocological data set, which were not available during the golden age of this paradigm, when indirect evidence was considered satisfactory to support it.

scholarly journals Paleontology of the Bears Ears National Monument: history of exploration and designation of the monument

2018 ◽  
Author(s):  
Jessica Uglesich ◽  
Robert J Gay ◽  
M. Allison Stegner ◽  
Adam K Huttenlocker ◽  
Randall B Irmis
Keyword(s):  
Fossil Record ◽  
Landscape Scale ◽  
Ice Age ◽  
Bureau Of Land Management ◽  
National Monument ◽  
Resource Protection ◽  
History Of ◽  
Last Ice Age ◽  
Dry Climates ◽  
Cretaceous Period

Bears Ears National Monument (BENM) is a new, landscape-scale national monument jointly administered by the Bureau of Land Management and the Forest Service in southeastern Utah as part of the National Conservation Lands system. As initially designated, BENM encompasses 1.3 million acres of land with exceptionally fossiliferous rock units. These units comprise a semi-continuous depositional record from the Pennsylvanian Period through the middle of the Cretaceous Period. Additional Quaternary and Holocene deposits are known from unconsolidated river gravels and cave deposits. The fossil record from BENM provides unique insights into several important paleontological periods of time, including the Pennsylvanian-Permian transition from fully aquatic to more fully terrestrial tetrapods; the rise of the dinosaurs following the Triassic-Jurassic extinction; and the response of ecosystems in dry climates to sudden temperature increases at the end of the last ice age and across the Holocene. While the paleontological resources of BENM are extensive, they have historically been under-studied. Here we summarize prior paleontological work in BENM and review the data used to support paleontological resource protection in the 2016 BENM proclamation.

The Quaternary: History of an Ice Age

2012 ◽  
pp. 409-428 ◽  
Author(s):  
P. L. Gibbard ◽  
N. H. Woodcock
Keyword(s):  
Ice Age ◽  
History Of ◽  
Quaternary History

Vegetation disturbance and human population in Colombia – a regional reconstruction

Antiquity ◽  
2004 ◽  
Vol 78 (302) ◽  
pp. 828-838 ◽  
Author(s):  
Robert Marchant ◽  
Hermann Behling ◽  
Juan Carlos Berrio ◽  
Henry Hooghiemstra ◽  
Bas van Geel ◽  
...  
Keyword(s):  
Human Activities ◽  
Human Population ◽  
Ice Age ◽  
Pollen Record ◽  
Landscape Changes ◽  
The Andes ◽  
Vegetation Disturbance ◽  
The People ◽  
Regional Reconstruction ◽  
Last Ice Age

Palaeoecologists using pollen to map vegetation since the last ice age have noted numerous changes – which they feel increasingly obliged to blame on humans. These changes, such as deforestation or the dominance of certain plants, may happen suddenly or take place over thousands of years. The authors study the pollen record in Colombia, identify plants diagnostic of cultivation or disturbed ground (“degraded vegetation”) and use them to map human activities by proxy. They show how the people move and the landscape changes between 5000 BP and the present day, from the coast inland, and from the lowlands up into the Andes.

The Environmental History of the Near and Middle East since the Last Ice Age

1980 ◽  
Vol 70 (4) ◽  
pp. 481
Author(s):  
John F. Kolars ◽  
William C. Brice
Keyword(s):  
Middle East ◽  
Environmental History ◽  
Ice Age ◽  
History Of ◽  
Last Ice Age

scholarly journals Introduction

2014 ◽  
Vol 47 (2) ◽  
pp. 221-244
Author(s):  
Eli Rubin
Keyword(s):  
Early Modern ◽  
Middle Ages ◽  
Early Modern Period ◽  
Ice Age ◽  
Special Issue ◽  
Open Spaces ◽  
Modern Period ◽  
History Of ◽  
Last Ice Age ◽  
The City

The essays in this special issue all focus on the city of Berlin, in particular, its relationship with its margins and borders over thelongue dureé. The authors—Kristin Poling, Marion Gray, Barry Jackisch, and Eli Rubin—all consider the history of Berlin over the last two centuries, with special emphasis on how Berlin expanded over this time and how it encountered the open spaces surrounding it and within it—the “green fields” (grüne Wiesen) referred to in the theme title. Each of them explores a different period in Berlin's history, and so together, the essays form a long dureé history of Berlin, although each of the essays in its own way explores the roots of Berlin's history in deeper time scales, from the early modern period, to the Middle Ages, and even to the very end of the last ice age, more than 10,000 years ago.

Geochemical and mineralogical characterization of sediments from Lake Futalaufquen (42.8°S, Andean Patagonia) to evaluate their potential as paleoclimatic proxies

2020 ◽  
Vol 98 ◽  
pp. 1-18
Author(s):  
Romina Daga ◽  
Sergio Ribeiro Guevara ◽  
Andrea Rizzo ◽  
Polona Vreča ◽  
Sonja Lojen ◽  
...  
Keyword(s):  
Atmospheric Transport ◽  
Ice Age ◽  
Long Distance ◽  
Mineralogical Characterization ◽  
Depositional History ◽  
Medieval Climatic Anomaly ◽  
Northern Patagonia ◽  
The Andes ◽  
History Of ◽  
Tephra Layers

AbstractLake sediments are key archives for paleoenvironmental investigation as they provide continuous records of the depositional history of the lake and its watershed. Lake Futalaufquen (42.8°S) is an oligotrophic waterbody located in Los Alerces National Park in the Andes of northern Patagonia, South America. A sedimentary sequence covering 1600 years was recovered to analyze the potential for paleoenvironmental reconstructions of the last millennia. Integration of different geochemical and mineralogical parameters and comparison with climatic reconstructions from other Patagonian records give clues for the identification of a warm period around AD 800–1000, associated with the Medieval Climatic Anomaly. The high frequency of tephra layers beginning in the mid-sixteenth century precludes identification of the Little Ice Age, recorded in northern Patagonia as a cold period from the fourteenth to the eighteenth century. Furthermore, the parameters analysed do not provide evidence of late-twentieth-century global warming. However, Zn deposition, a long-distance atmospheric transport process of anthropogenic origin, was identified during the last century.

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