Paleotemperature method

Reconstruction of faunal records in deep-sea sediments and oxygen isotope measurements have been yielding useful information of the ocean s paleotemperature. However, the lack of these tools in the case of continents has hampered the estimation of paleotemperature in continents. The latter estimate has mainly been made on somehow indirect approach such as pollen data, periglacial feature, and soil carbonate, all of which suffer from considerable uncertainty stemming from the assumption that must be made to convert the observation to temperature. The advantage of the noble gas thermometer, as compared to the other paleotemperature methods, is that it is based on the relatively simple physical principle that directly relates noble gas concentration to the ambient temperature (see Stute Schlosser, 1993, for a recent review of the noble gas paleotemperature method). However, in actual practice, we need some cautions. 

Muller P. J., CepekM., RuhlandG., and Schneider R. R. (1997) Alkenone and coccolithophorid species changes in late quaternary sediments from the Walvis ridge implications for the alkenone paleotemperature method. Palaeogeogr. Palaeoclimatol. Palaeoecol. 135,71-96. 

One of the first apphcations of the paleotemperature method was undertaken by Harold Urey et al. (1951), who analyzed incremental sections along the radius of the shell of a fossil belemnite (a type of cephalopod). This bullet-shaped shell, from the Cretaceous PeeDee formation of South Carolina, was the original standard material for 5 C analysis (Table 5.2). The isotopic diary of the PeeDee belemnite (Fig. 5.4) records four cool extremes separated by three warm periods, in what appears to be 3.5 y of life history laid down approximately sixty million years ago. The absolute temperature scale is uncertain, because the 5 0 of the ancient sea where the belemnite lived is unknown. 

The following is a derivation of the relations between K, a, 6 and for the oxygen isotope exchange reaction between CO3 and H2O that is the basis of the paleotemperature method. For the reaction... 

VillanuevaJ., FloresJ.A., Grimalt J.O. (2002) A detailed comparison of the Uj7 and coccolith records over the past 290 kyears implications to the alkenone paleotemperature method. Org. Geochem. 33, 897-905. 

Tudge, A.P. 1960 A method of analysis of oxygen isotopes in orthophosphate-its use in the measurement of paleotemperatures. Geochimica et Cosmochimica Acta 18 81-93. 

Meyer HW (2007) A review of paleotemperature-lapse rate methods for estimating paleoelevation from fossil floras. Rev Mineral Geochem 66 155-171... 

A Review of Paleotemperature-Lapse Rate Methods for Estimating Paleoelevation from Fossil Floras... 

Paleoelevation models based on fossil floras use three different approaches 1) the use of floras to estimate temperature, which is used in combination with lapse rates to infer elevation 2) the use of floras to estimate enthalpy, which is used with gravitational acceleration to estimate elevation and 3) the use of stomatal frequency in leaves to indicate altitudinal changes in C02 partial pressure. This paper will focus on the first of these, the temperature-lapse rate method, which itself has three basically different approaches that differ in the way paleotemperatures can be estimated from fossil floras and in the methods by which lapse rates can be utilized in the calculations. The purpose of this paper is to provide a concise overview that summarizes... 

Estimates of paleotemperature from fossil floras provide the primary data on which paleoelevation estimates are based. Two fundamentally different approaches have been used in paleobotany to acquire these data. The first is based on the climatic distribution of nearest living relatives (the NLR method, also sometimes referred to as the floristic method), and the second has its basis in the correlation of plant physiognomic characters with climate. 

To apply these methods to a paleoclimate problem, one tacitly assumes that the errors as estimated from today s climate and plants are similar to those of the past. The deposition of plant fossils appears not to affect our climate estimates. Combining the estimated uncertainties indicates an altitude error of 910 m and compares favorably with altitude errors of 1100-1400 m from differences in paleopressure (Sahagian and Maus 1994) and 800-1500 m from differences in paleotemperature. 

Axelrod DI (1966) A method for determining the altitudes of Tertiary floras. Paleobotanist 14 144—171 Axelrod DI, Bailey HP (1969) Paleotemperature Analysis of Tertiary Floras. Palaeogeog Palaeoclim Palaeoecol 6 164-195... 

The concentration of the atmospheric noble gases dissolved in groundwaters, coupled with the dating of the respective groundwaters, provides a most valuable method to reconstruct paleotemperatures. The work done so far in this field by various researchers (section 13.8) demonstrates the applicability of the method and thus opens a most promising field of research. The future of this field encompasses several tasks ... 

Bowen, R. Paleotemperature analysis. In Methods in Geochemistry and Geoph., Ser. 2,... 

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