Cenozoic

The Cenozoic portions of the Gulf Coast sedimentary basins are immature therefore, little cementing of the sediments has taken place. Poisson s ratio varies with depth for such sedimentary columns, reflecting the variation of properties through the column. At great depth (i.e., approaching 20,000 ft), Poisson s ratio approaches that of incompressible, plastic materials (i.e., 0.5) [35]. 

Cenozoic Tertiary 66 Myr Climate Cools. Continents nearing modern positions. Drying trend in middle of period. Radiation of birds, mammals, flowering plants, pollinating insects... 

Hughes, T. J. (1985). The great Cenozoic ice sheet. Palaeogeogr. Palaeoclim. Palaeoecol. 50,9-43. 

Raymo, M. E. and Ruddiman, W. F. (1992). Tectonic forcing of late Cenozoic climate. Nature 359, 117-122. 

Wang, Y., Cerling, T.E. and MacFadden, B.J. 1994 Fossil horses and carbon isotopes new evidence for Cenozoic dietary, habitat, and ecosystem changes in North America. Palaeogeography, Palaeoclimatology, Palaeoecology 107 269-279. 

Hsii, J. 1983. Late cretaceous and Cenozoic vegetation in China, emphasizing their connections with North America. Ann. Missouri Bot. Gard. 70 490-508. 

Figure 1.4. Comparison of quantities of ore deposits formed in late Cenozoic in NE and SW Japan. Weight per kilometer length of island arc (Ishihara, 1978).

Figure 1.6. Di.stribution and temporal and spatial relationship of late Cenozoic gold deposits in the Japanese Islands. 1 Quartz vein-type gold deposits with little to no base metals. 2 Gold-silver deposits with abundant base metals. 3 Distribution boundary of gold deposits formed during the Miocene. 4 Location of Plio-Pleistocene gold deposits at the actual island arc junctions. 5 Location of Plio-Pleistocene gold deposits in front of the actual island arc junctions. Numbers in the figure are K-Ar ages of epithermal Au-Ag veins (Kubota, 1994).

Figure 1.146, Stre.ss trajectory map.s of southern Northeast Honshu in the late Cenozoic period, after Tsunakawa and Takeuchi (1986) with a slight addition. oh, . trajectory is drawn by smoothing the inferred stress orientations from the selected dike-swarms with K-Ar dates. Selected major faults with age estimation are also shown for indicating types of stress fields. T Extensional stress field, where ay > a 2>cth , and normal or gravity faulting is preferable. P Compre.ssional, oh > ay, reverse or thrust faulting...

Figure 1.164. Distribution of Cenozoic basalts and active rift systems in the northeast China region. Arrows indicate the horizontal convective current in the upper mantle associated with the upwelling of the asthenosphere beneath the region. A Baikal Rift B Shanxi Graben C Tancheng-Lujiang Fault D Okinawa Trough (Tatsumi et al., 1990).

Chinzei, K. (1991) Late Cenozoic zoogeography of the sea of Japan area. Episodes, 14, 231-235. 

Graham, D.D., Bender, M.L., Williams, D.F. and Keigwin, L.D. Jr. (1982) Strontium-calcium ratios in Cenozoic planktonic foraminifera. Geochim. Cosmochim. Acta, 46, 1281-1292. 

Horikoshi, E. (1976) Development of late Cenozoic petrogenetic provinces and metallogeny in northeast Japan. Geol. Assoc. Canada Special Paper, 14, 121-142. 

Ikebe, N. (1978) Bio- and chronostratigraphy of Japanese Neogene with remarks in paleogeography. Cenozoic Geology of Japan. Prof, Ikebe, Y. Mem. Vol., Osaka U., 13-34 (in Japanese). 

Ishihara, S. and Sasaki, A. (1994) Sulfur isotopic characteristics of late Cenozoic ore deposits at arc junction of Hokkaido, Japan. The Island Arc, 3, 122-130. 

Kitazato, H. (1975) Geology and age of upper Cenozoic formation in Oga Peninsula. Tohoku Geology Paleontology, 75, 17-49. 

Kubota, Y. (1994) Temporal and spatial relationship and significance of island arc junction on the late Cenozoic gold deposits in the Japanese Islands. Resource Geology, 44, 17-24 (in Japanese). 

Otofuji, Y. (1996) Large tectonic movement of the Japan Arc in late Cenozoic times inferred from paleomag-netism Review and Synthesis. The Island Arc, 5, 229-249. 

Shikazono, N. (1987a) Origin of Cenozoic ore sulfur. Monthly Earth, 9, 595-601 (in Japanese). 

Sugimura, A., Matsuda, T, Chinzei, K. and Nakamura, K. (1963) Quantitative distribution of late Cenozoic volcanic materials in Japan. Bull. Volcanol., 26, 125-140. 

Takeuchi, A. (1987) On the episodic vicissitude of tectonic stress field of the Cenozoic Northeast Honshu arc, Japan. In Nasu, N. et al. (eds.), Formation of Active Ocean Margins, D. Reidel Publ., pp. 443-468. 

Yamagishi, H. and Watanabe, Y. (1986) Change of stress field of late Cenozoic southwest Hokkaido, Japan. 

According to the summary of the development of back-arc basins in the Cenozoic age by Tamaki and Honza (1991) (Figs. 3.3 and Fig. 3.4) and Kaiho and Saito (1994) (Fig. 3.5), many back-arc basins (Japan Sea, Kuri, Shikoku, Parece Vela, South China, Sulu, Makassar, Central Scotia, Cayman) widely and rapidly developed during 30-15 Ma. 

Fig. 4.1. Isotopic paleotemperature analyses of planktonic and benthic foraminifera from the sub-Antarctic Pacific indicating considerably warmer conditions in the Early Cenozoic (Shackleton and Kennett, 1975a).

Fig. 4.4. Histograms of middle to late Cenozoic K-Ar dates with relative volumetric estimates of igneous rocks (Kennett et al., 1977).

Fig. 4.3. (A) Composite multispecies benthic foraminiferal Mg/Ca records from three deep-sea sites DSDP Site 573, ODP Site 926, and ODP Site 689. (B) Species-adjusted Mg/Ca data. Error bars represent standard deviations of the means where more than one species was present in a sample. The smoothed curve through the data represents a 15% weighted average. (C) Mg temperature record obtained by applying a Mg calibration to the record in (B). Broken line indicates temperatures calculated from the record assuming an ice-free world. Blue areas indicate periods of substantial ice-sheet growth determined from the S 0 record in conjunction with the Mg temperature. (D) Cenozoic composite benthic foraminiferal S 0 record based on Atlantic cores and normalized to Cibicidoides spp. Vertical dashed line indicates probable existence of ice sheets as estimated by (2). 3w, seawater S 0. (E) Estimated variation in 8 0 composition of seawater, a measure of global ice volume, calculated by substituting Mg temperatures and benthic 8 0 data into the 8 0 paleotemperature equation (Lear et al., 2000).

In addition to hydrothermal and volcanic activity, metamorphism may have influenced the CO2 levels of the atmosphere and caused climate changes. Based on a model of the Cenozoic extension in the North American Cordillera, Nesbitt et al. (1995) demonstrated that CO2 generation associated with crustal extension may have been a major contributor to the elevated CO2 levels of the Cenozoic atmosphere and the resulting global warming due to the CO2 greenhouse effect. 

PCO2 values were estimated by 8 C method by Cerling (1984, 1991, 1992a,b) who used 8 C of carbonates in terrestrial soil as an indicator of PcOi- However, these data on Cenozoic age are scarce and scattered. 

Ceding, T.E. (1991) Carbon dioxide in the atmosphere evidence from Cenozoic and Mesozoic paleosols. Am. J. Sci., 291, 377 00. 

Chinzei, K. (1986) Faunal succession and geographic distribution of Neogene molluscan faunas in Japan. In Kotaka, T. (ed.), Japanese Cenozoic Molluscs — Their Origin and Migration. Palaeont. Soc. Japan, Special Paper, 29, 17-32. 

Godderis, Y. and Francois, L.M. (1995) The Cenozoic evolution of the strontium and carbon cycles relative importance of continental erosion and mantle exchange. Chem. Geol., 126, 169-190. 

Kashiwagi, H., Shikazono, N. and Tajika, E. (2000) Global carbon cycle model in the Cenozoic. 10th Annual V.M. Goldschmidt Conference, September 3-8, Oxford University Abst. 

Kerrick, D.M. and Caldeira, K. (1993) Paleoatmospheric consequences of CO2 released during early Cenozoic regional metamorphism in the Tethyan orogen. Chem. Geol., 108, 205-230. 

Lear, C.H., Elderfield, H. and Wilson, P.A. (2000) Cenozoic deep-sea temperatures and global ice volumes from Mg/Ca in benthic foraminiferal calcite. Science, 287, 269-272. 

Nesbitt, B.E., Mendoza, C.A. and Kerrick, D.M. (1995) Surface fluid convection during Cordillera extension and the generation of metamorphic CO2 contributions to Cenozoic atmospheres. Geology, 23, 99-101. 

Raymo, M.E., Ruddiman, W.F. and Froelich, P.N. (1988) Influence of late Cenozoic mountain building on ocean geochemical cycles. Geology, 16, 649-653. 

---