Climate in Earth History Studies in Geophysics (1982) / Chapter Skim
Currently Skimming:
21 Paleozoic Data of Climatological Significance and Their Use for Interpreting Silurian-Devonian Climate
21 Paleozoic Data of Climatological Significance and Their Use for Interpreting Silurian-Devonian Climate
Pages 189-198
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 189... ...
However, only in the past few decades, particu arty with the advent of plate tectonic concepts, has this information begun to be synthesized in a manner that makes it usable to the climatologist. Lithofacies data with climatic implications, for example, are now available for the Paleozoic on a global scale, and biogeographic data are being synthesized for the major time intervals.
|
From page 190... ...
provided an excellent global summary of the distribution of Paleozoic coal deposits. Coals are virtually absent prior to the Late Devonian, when, presumably for the first time, enough land plant debris became available in suitahle preservational sites to provide material for extensive coal deposits.
|
From page 191... ...
It must be borne in mind, however, that the adaptive significance of morphological characters of largely extinct plants, unrelated or only distantdy related to living plants, may he different, particularly if there is conflicting biological and/or physical information. Moreover, the precise climatic variable—for example, temperature or moisture—to which the adaptation is a physiological response is not always clear, even when interpreting varied morphological features in modern plants (see Dolph and Dilcher, 1979)
|
From page 192... ...
In addition, it is essential to recognize that the presence or absence of tree rings in woody stems may be an unreliable guide in smne circumstances to present climatic oondihons, and by implicatim~ to climatic conditions of the past. For example, Tomb son and Craighead (1972)
|
From page 193... ...
is frequendy a prerequisite, to enable groundwater level changes and/or the drying of seepages that lead to the irreversible hardening of the accumulated sesquloxides." Widespread Lower and Upper Devonian caleretes in the Caledonian Belt of Britain, and from Nova Scotia to New York in the Appalachian Belt, as well as in the Upper Devonian of Antarctica and the Lower Devonian of southwestern China help to extend the arid zone into those regions, although the abeence of evaporites in all of them previously provided somewhat ambiguous climatic information. The occurrenoe of IJp per Devonian coal in North America (Heckel and Witzke, 1979)
|
From page 194... ...
If there data prove re liable, they should provide wind velocities for some Paleozoic aeolian deposits-, as well as velocities for "f eating" quartz grains found here and there in marine sediments. SUMMARY OF SILURIAN AND DEVONIAN CLIMATES We have discussed categories of data that have proved useful, or are potentially useful, in reconstructing Paleozoic climates.
|
From page 195... ...
In the Eifeleian, the Smith China Region is distinct from coeval faunas pre ent in the Shan Stales of Burma. The closest affinities of the latter are with the RhenishBohemian Region The Late Devonian biofacies and lithofacies data net estate a major shift of the Devonian continental unfed from the position shown here to one with a closer approach to the geography of the Carbuniferous.
|
From page 196... ...
On these should be plotted the boundaries of biogeographic units, li hulogdc data (distribution of redbuds, carbonate-noncarbonate rock sequenoes, evaporite and coal deposits, paleosol and glacial deposits, and phosphorites of the upwelling type) , mountain belts, and biological information of environmental significance.
|
From page 197... ...
Habicht (1979) presented a similar anomaly for the Cambrian of North Africa, where the Early Cambrian includes many marine carbonate beds, indicators of warm climatic regime, whereas the MiddDe and Late Cambrian lacks carbonates and is characterized by a cool climate marine fauna.
|
From page 198... ...
palaensols in f Vial redbeds of the Aztec Siltstone (Upper Devonian) , southern Victoria Land, Antarctica, Sed.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.