|
Search over 100 encyclopedias and dictionaries: |
Research categories | Follow us on Twitter |
Research categories
View all topics in the newsView all reference sources at Encyclopedia.com |
|||
palaeoclimatology
palaeoclimatology Palaeoclimatology is the study of past climate and its variation in space and time during the period before instrumental measurements began to be made. A key aim of palaeoclimatology over and above the simple documentation of past climates is to elucidate the mechanisms that gave rise to the observed variations. This entails both the collection of proxy records of climatic oscillations and the establishment of a timescale for their occurrence. The sources of proxy data are various: biological (e.g. dendroclimatology, pollen grains, plant and animal macrofossils); terrestrial (e.g. ice cores, glacial and periglacial sediments and landforms, aeolian sediments, lacustrine [lake] deposits, speleothems [chemical deposits found in caves] and pedological evidence); and marine (e.g. floral and faunal abundance and morphology, mineral composition, dust and glacial debris concentrations, and geochemical data), as well as other geological evidence and stable isotopic data. The preserved climatic record is frequently complex, incomplete, and exhibits considerable extraneous ‘noise’ from non-climatic influences. The palaeoclimatic record does, nevertheless, indicate large shifts from glacial to interglacial conditions, with, in some instances, abrupt shifts between climatic modes.
The most significant global-scale mechanism that is currently invoked to explain glacial–interglacial climatic fluctuations during the past 2.5 million years is embodied in the Croll–Milankovich theory of ice ages. This theory relates the changes in climate to periodic variations in the orbit of the Earth round the Sun which take place at intervals of about 100, 42, and 19–23 thousand years. Stephen Stokes |
|
|
Cite this article
PAUL HANCOCK and BRIAN J. SKINNER. "palaeoclimatology." The Oxford Companion to the Earth. 2000. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. PAUL HANCOCK and BRIAN J. SKINNER. "palaeoclimatology." The Oxford Companion to the Earth. 2000. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O112-palaeoclimatology.html PAUL HANCOCK and BRIAN J. SKINNER. "palaeoclimatology." The Oxford Companion to the Earth. 2000. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O112-palaeoclimatology.html |
|
palaeoclimatology
palaeoclimatology The study of past climates from the traces left behind in the geologic record. It is assumed that the uniformitarian principle has obtained, but this may not be the case, and the geologic data are always insufficient for palaeoclimatological purposes. Dating methods and palaeogeographic reconstructions are suspect, and often fossil faunas and floras cannot be related easily in terms of time. Most glacial strata can be dated only within wide limits and many climatic criteria leave no mark in the rocks.
|
|
|
Cite this article
AILSA ALLABY and MICHAEL ALLABY. "palaeoclimatology." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "palaeoclimatology." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O13-palaeoclimatology.html AILSA ALLABY and MICHAEL ALLABY. "palaeoclimatology." A Dictionary of Earth Sciences. 1999. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-palaeoclimatology.html |
|
palaeoclimatic indicator
palaeoclimatic indicator One of the sources from which evidence concerning past climates can be obtained. Such indicators include glacial, periglacial, and pluvial deposits, which provide morphological information related to climate and cave deposits, dunes, and dunefields, which yield lithologic information. Plants (including pollen; see also leaf physiognomy), molluscs, foraminifera, beetles (see beetle analysis), and ostracods are among the organisms that have been used to derive biotic information.
|
|
|
Cite this article
MICHAEL ALLABY. "palaeoclimatic indicator." A Dictionary of Ecology. 2004. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "palaeoclimatic indicator." A Dictionary of Ecology. 2004. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O14-palaeoclimaticindicator.html MICHAEL ALLABY. "palaeoclimatic indicator." A Dictionary of Ecology. 2004. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-palaeoclimaticindicator.html |
|
palaeoclimatic indicator
palaeoclimatic indicator One of the sources from which evidence concerning past climates can be obtained. For example, glacial, periglacial, and pluvial deposits provide morphological information related to climate; cave deposits, dunes, and dune-fields yield lithologic information; and plants (including pollen), molluscs (Mollusca), foraminifera (Foraminiferida), beetles, and ostracods (Ostracoda) are among the organisms that have been used to derive biotic information.
|
|
|
Cite this article
AILSA ALLABY and MICHAEL ALLABY. "palaeoclimatic indicator." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "palaeoclimatic indicator." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O13-palaeoclimaticindicator.html AILSA ALLABY and MICHAEL ALLABY. "palaeoclimatic indicator." A Dictionary of Earth Sciences. 1999. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-palaeoclimaticindicator.html |
|
palaeoclimatology
palaeoclimatology The study of climates of earlier geological periods. This is based largely on the study of sediments that were laid down during these periods and of fossils. The changes in the positions of the continents as a result of continental drift and plate tectonics complicate the study.
|
|
|
Cite this article
"palaeoclimatology." A Dictionary of Biology. 2004. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. "palaeoclimatology." A Dictionary of Biology. 2004. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O6-palaeoclimatology.html "palaeoclimatology." A Dictionary of Biology. 2004. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-palaeoclimatology.html |
|
palaeoclimatology
palaeoclimatology The study of past climates from fossils and traces left in the geologic record. See beetle analysis; leaf physiognomy; palaeoclimatic indicator; pollen analysis; and varve.
|
|
|
Cite this article
MICHAEL ALLABY. "palaeoclimatology." A Dictionary of Ecology. 2004. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "palaeoclimatology." A Dictionary of Ecology. 2004. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O14-palaeoclimatology.html MICHAEL ALLABY. "palaeoclimatology." A Dictionary of Ecology. 2004. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-palaeoclimatology.html |
|
Search over 100 encyclopedias and dictionaries:
HighBeam™ Research, Inc. © Copyright 2012. All rights reserved.
The Encyclopedia.com advertising network includes:
