Interglacial periods

Figure 2a. Carbon dioxide concentrations in the atmosphere have varied over the glacial cycles of the earth s history, with high vjues at of around 300 during the interglacial period approximately 130,000 years ago...

Chen JH, Curran HA, White B, Wasserbmg GJ (1991) Precise chronology of the last interglacial period 238 j/23o-pjj fossil coral reefs in the Bahamas. Geol Soc Amer Bull 103 82-97... 

Hall BL, Henderson GM (2001) Use of TIMS uranium-thorium dating to determine past reservoir effects in lakes Two examples from Antarctica. Earth Planet Sci Lett 193 565-577 Hamelin B, Bard E, Zindler A, Fairbanks RG (1991) " U/ U mass spectrometry of corals How accurate is the U-Th age of the last interglacial period. Earth Planet Sci Lett 106 169-180 Hanebuth T, Stattegger K Grootes PM (2000) Rapid flooding of the Sunda Shelf a late-glacial sea-level record. Science 288 1033-1035... 

Min GR, Edwards RL, Taylor FW, Recy J, Gallup CD, Beck JW (1995) Annual cycles of U/Ca in corals and U/Ca thermometry. Geochim Cosmochim Acta. 59 2025-2042 Moore WS (1981) The thorium isotope content of ocean water. Earth Planet Sci Lett 53 419-426 Moran SB, Hoff JA, Edwards RL, Landing WM (1997) Distribution of Th-230 in the Laborador Sea and its relation to ventilation. Earth Planet Sci Lett 150 151-160 Muhs DR, Simmons KR, Steinke B (2002) Timing and warmth of the Last Interglacial period new U-series evidence from Hawaii and Bermuda and a new fossil compilation for North America. Qrrat Sci Rev 21 1355-1383... 

Slowey NC, Henderson GM, Curry WB (1995) Direct dating of the last two sea-level highstands by measurements of U/Th in marine sediments from the Bahamas. EOS 76(46) 296-297 Slowey NC, Henderson GM, Curry WB (1996) Direct U-Th dating of marine sediments from the two most recent interglacial periods. Nature 383 242-244... 

Adkins JF, Boyle EA, Keigwin LD, Cortijo E (1997) Variability of the North Atlantic thermohaline circulation during the last interglacial period. Nature 390 154-156 Anderson RF (1982) Concentration, vertical flux and remineralization of particulate uranium in seawater. Geochim Cosmochim Acta 46 1293-1299... 

More subtle use of the probability distributions obtained from Monte Carlo simulations of °ThAJ analyses. For example, Rowe et al. (1999) were able to incorporate geologic and stratigraphic information which constrained the age of two samples two within the same interglacial period, permitting a significant improvement in the age uncertainty for both of the two samples. 

Jones 2001). According to sea level changes, the last Ice Age, centered at 18,000 years ago, was even colder than now (3-4 C) (Lamheck 2001). In contrast, the Medieval Warm Period was wanner than now (0.5 C), and both the Interglacial Period (130,000 y from now) and the Eocene Warm period (33-53 My from now) were even warmer (3-4 C) (Webb 1992). 

The last big ice age on Earth ended about 12,000 years ago. Today, most scientists believe we are still coming out of that cold period into an interglacial period. An interglacial period is the time between ice ages when Earth is relatively warm. But just as scientists cannot determine why ice ages begin, they cannot determine why they end, either. It is only known that when carbon dioxide levels rise, the Earth starts to get warm. 

The evolution of the current interglacial period is different from its predecessors in that it was during this time that humans evolved. They learned to use tools, manage fire, hunt, gather, and assert some control over their immediate environment. Through this evolution, they started to move carbon in different ways as well. When humans learned to burn and manage fire, they started to add carbon dioxide to the atmosphere. 

Interglacial period A period between ice ages when Earth is relatively warm. 

M. Anklin et at, Climate Instability During the Last Interglacial Period Recorded in the GRIP Ice Core." Nature 1993,364.203.]... 

Analysis of the data on temperature measured in boreholes made an important contribution ito ideas about SAT changes in the past. For instance, Bodri and Cermak (1999) noted that if the amplitude of long-term SAT variations during transitions from glaciations to interglacial periods had reached 10K-15K in the Holocene (the last 10,000-14,000 years), changes of several °K would have taken place on time scales from decades to centuries. In this connection, analysis has been made of the data on the vertical profiles of temperature measured at different depths in boreholes, and maps have been drawn of SAT changes over the Czech Republic, which took place between 1100 bc to 1300 bc (small climatic optimum), between 1400 and 1500, and between 1600 and 1700 (main phases of the Little Ice Age). 

Information on the content of carbon dioxide and methane in air bubbles contained in ice kerns reflects the important role of these minor gas constituents (MGCs) in climate formation, but it is still unclear what took place first change in temperature or in MGC content. For instance, it was recently shown that during four interglacial periods, changes in temperature in the Antarctic took place about 4,000 years before the changes in C02 concentration. 

Figure 2.1 Changes in mean sea level within the Pleistocene as a result of different interglacial periods. (Modified from Fairbridge, 1961.)...

Modern estuaries are recent features that only formed over the past 5000 to 6000 years during the stable interglacial period of the middle-to-late Holocene epoch (0-10,000 y BP), which followed an extensive rise in sea level at the end of the Pleistocene epoch (1.8 My to 10,000 y BP). 

With the crude age one can estimate the paleoenvironmental conditions in terms of glacial or interglacial period, sea level, distance of paleorecharge area from the seashore, season of major recharge, altitude of the former water table, former evapotranspiration intensity, or the type of plant community that prevailed at the studied paleorecharge site. These considerations should lead to the selection of the pertinent paleo-input functions. 

---