Abstract
The knowledge that hydrostatic pressure is equal to the gravity value of the overlying rocks in studying a dynamic state of certain underground site is argued. It is suggested that the stress field Τ in the crust is a combination or superposition of total hydrostatic pressureP with differential stress σ, and the total hydrostatic pressureP at any point in the crust comprises two parts: one is spherical stress tensor PG, caused by the gravity, and the other is spherical stress tensor PS caused by tectonic stress; thereforeP could not be attributed to the gravity of overlying rocks only.
The results obtained by a finite-element simulation indicate that the tectono-original additional hydrostatic pressures PS decrease gradually from the compressive zone (P SC ) to the shear zone (P sSH ) and to the tensile zone (P sT ), i.e. P SC > P sSH > P sT . in the same depth. On the basis of the above-mentioned research, the method of measurement and calculation of metallogenetic depth corrected by PS is established, i.e. first tectonic additional hydrostatic pressure PS is removed from general hydrostatic pressureP to get PG, gravity additional pressure, then accordingly the depth data are measured and calculated.
The plastic deformation of garnet in ccesite-bearing eclogite, quartz eclogite and garnet amphibolite of the ultrahighpressure metamorphic (UHPM) complex in the Yingshan County in Dabie Mt. is studied by the transmission electron microscope (TEM). It is shown that the garnets have ductile deformation in the metamorphic condition of eclogite and amphibolite facies. Microstructures of the garnet vary greatly among coesite-bearing eclogite, quartz eclogite and garnet amphibolite.
The tectonic principal stress in three-dimensional space and the tectonic additional hydrostatic pressure are reconstructed by differential stress and strain ratio (α) of garnet in minor coesite-bearing eclogite, then the gravity and thickness of overlying rocks are determined. The formation depth of ⩾ 32.09–32.106 km of the coesite-bearing eclogite in Yingshan County in the Dabie UHPM zone is obtained from difference PG which ms fromP minus PS PS = (σ1 + σ2 + σ3)/3. The value ofP is 2.8 GPa resulting from Qz-coes geobarmeter. This result is at all different from other researchers’ conclusion that the formation depth of eclcgite in Dabie UHPM zone is ⩾ km by the method of weight/ special weight (W/SW). The strong tectionic action makes a great contribution to the formation of eclogite in the Dabie UHPM zone at so shallow depth of about 32 km, therefore it is thought that attention should be paid to the tectono-original additional hydrostatic pressure in the study on UHPM zone.
Similar content being viewed by others
References
Ramsay, J. G.,Folding and Fracturing of Rocks, New York: MacGraw hill, 1967, 586.
Harker, A.,Metamorphism: A Study of the Transformations of Rock Masses (in Chinese), Beijing: Geological Publishing House, 1981, 1–373.
Wang Jiayin,Introduction of Stress Minerals, Beijing: Peking University Press, 1978, 1–238.
Yang Kaiqing, Research subjects and orientation of the theory of tectono-petrogenesis and tectono-metallogenesis,Bulletin of the Institute of Geomechanics CAGS (in Chinese), 1986(7): 1.
Liu Ruixun,Microstructural Geology (in Chinese), Beijing: Peking University Press, 1988, 1–235.
Jones, M. E., The relationships between metamorphism and deformation of rock,J. Struct., Geol., 1981, 3(3): 333.
Li Xiaobo,Metallogenesis and Geodynamics: Frontiers of Geological Sciences in 1990’s: Research Priorities for China (in Chinese), Wuhan: China University of Geosciences Press, 1993, 49–54.
Zhang Ronghua, Hu Shumin, J. Posey-Dowtyet al., Tinetics studies of mineral-water reactions in hydrothermal flow systems at elevated temperature and pressure,Science in China, Ser. B, 1990, 33(9): 1136.
Carpenter, J. R., Apparent retrograde metamorphism: another example of the influence of structural deformation on metamorphic differentiation,Contr. Miner. Petrol., 1986, 17: 173.
Caron, J. M., Potdevin, J. L., Sicard, E., Solution deposition processes and mass transfer in the deformation of a minor fold,Tectonophysics, 1987, 135(1–3): 77.
Zhou Jiyuan, Yu Zhuchen, Mao Yuyuanet al., Ore solution migration and ore prognostication:Selected Papers on Geomechanics, No. 9, (in Chnese), Beijing: Geological Publishing House, 1989, 47–58.
Nishiwaki, The relationship between tectonic stress and formation of porphyry copper deposits,Foreign Geological Science and Technique (in Chinese), 1984(6): 97.
Xu Shutong, Liu Yican, Jiang Lailiet al., Symposium of the Researches on Modern Geology (in Chinese), Nanjing: Nanjing University Press, 1992, 157–165.
Doukhan, N., Sautter, V., Doh, J. C., Ultradeep, ultramafic mantle xenoliths: transmission electron microscopy preliminary results,Physics of the Earth and Planetary Interiors, 1994, 82: 195.
Jun-ichi Ando, Kiyoshi Fujino, Toru Tadeshita, Dislocation microstructures in naturally deformed silicate garnets,Physics of the Earth and Planetary Interiors, 1993, 80: 105. 411
Ji Shaocheng, Jaccques Martignole, Ductility of garnet as an indicator of extremely high temperature,Journal of Structural Geology. 1994, 16(7): 985.
Chen, J., Zhai, M. G., Ye, K., Coesite-beanng eclogite in Yingshan area, Hubei Province,Contributions to Mineralogy, Petrology and Geochemistry, Beijing: Petroleum Industry Press, 1996, 115–120.
Lü Guxian, A study on the ore field structure in Shicao Copper Deposit in Yanqing County, Beijing,Annual Report, Chinese Academy of Geological Snences (in Chinese and English), Beijing: Geological Publishing House, 1982, 192–194; 471–473.
Lü Guxian, Kong Qingcun,Geology of the Linglong-Jiaojia-Type Gold Deposits (in Chinese), Beijing: Science Press, 1993. 1–266.
Lü Guxian, On the influence of tectonic force on hydrostatic pressure,Chinese Science Bulletin (in Chinese), 1995, 40(3): 286.
Lü Guxian, On metallogenesis of dynamometamorphic skarns in Shicao copper deposit,Bulletin of the Institute of Geomechanics (in Chinese), 1986(7): 71.
Lü Guxian, On the tectono-petrofacies forms and the Linglong-Jiaojia-type gold deposits in the Jiaodong Peninsula, China,Bulletin of the Chinese Academy of Geological Sciences (in Chinese), 1991(23): 65.
Lü Guxian, Research and measurement of metallogenetic depth of the Linglong orefield, Shandong Province,Chinese Science Bulletin (in Chinese), 1995, 40(15): 1399.
Zhu Zhuoshan, Ren Yingchen, A research on genesis of both kinds of gold deposits of the Linglong type and the Jiaojia type, using the mathematic and statistic method,Geology and Mineral Resources Research (in Chinese), 1988, 13(3): 72.
Lü Guxian, Measurement and research method of metallogenic depths of Jiaojia orefield aand Linglong orefield, Shandong Province, China,Science in China, Ser. D, 1997, 40(5): 449.
Chen, J., Zhao, Z. Y., Wang, Q. M., Plastic flow of sphene in hgh presssure mylonite,Chinese Science Bulletin, 1995, 40: 655.
Chen Jing, Wang Qingchen, Zhai Mingguoet al., Plastic deformation of garnet in eclogite,Science in China, Ser. D, 1995, 39(1): 18.
Lü Guxian, The concept of tectonophysicochernistry,Regional Geology of China (in Chinese), 1991(3): 245.
Wnag Ren, Ding Zhongyi, Yin Youquan,Foundations of Solid Mechanics (in Chinese), Beiing: Geological Publishing House, 1979, 200.
Le Guangyu, Du Siqing, Stress summation and combined tectonics,Scientia Sinica (B) (in Chinese), 1986(8): 876.
Kozlovsky, E. A.,Superdeep Drillhole at Kola (in Chinese), Beijing: Geological Publishng House, 1989, 1–218.
Hassan, A. B., Jafar, H., Abdolali, B., Self-similar cataclasis in the Saltville thrust zone, Knoxville, Tennessee,J. Geophysical Research, 1995, 100(B9): 18075.
Murrell, S. A. F., Theology of lithosphere-experimental indications,Tectonophysics, 1976, 36: 5.
Yang Minzhi, Lü Guxian. TheGeology-Geochemistry of Gold Deposits of the Greenstone Belt of East Shandmg Province, China (in Chinese), Beijing: Geological Publishing House, 1996, 1–232.
Lü, Guxian, Liu, Ruixun, On the action of gravity and tectonic stress in earth crust,Geological Journal of Universities (in Chinese), 1996, 2(1): 28.
Ren Jishun, The continental tectonics of China,Acta Geoscientia Snica (in Chinese), 1994(3–4), 5.
Xiao Yilin, Fu Bin, Li Shuguanget al., Metamorphic P-T and oxygen isotope studies of eclogites from Bixiling in the Dabie Mountains,Acta Geoscientia Sinica (in Chinese), 1997, 18(3): 318.
Zheng Yongfei, Fu Bin, Xiao Yilinet al., Hydrogen and oxygen isotope composition of eclogites from the Dabie mountains and its geodynamic implications,Acta Geoscientia Sinica (in Chinese), 1997, 18(3): 336.
Wang Fangzheng, A discussion of forming depth of high-pressure and ultrahigh-pressure metamorphism,Earth Science—Journal of China University of Geoscience (in Chinese), 1996, 21(1): 41.
Powell, R., Regressiion diagnostics and robust in geothermometer/geobarometer calibration: the garnet-clinopyroxene geothermometer revisted,Journal of Metamorphic Geology, 1995, 3: 327.
Mirwald, P. W., Massonne, H. J., Quartz coesite transition and the comparative friction measurements in piston-cylinder appartus using talcalsirnag-glass (TAG) and NaCl high pressure cell: aNeues Jahrbuch für Mineralogie Monatshefte, 1980, 164: 469.
Holland, T. J. B., The reaction albite Jadeite + quartz determined experimentally in the range 600–1200°C,Am. Miner., 1980, 65: 129.
Holloster, L. S., Grissom, G. C., Peters, E. K.et al., Confirmation of the empirical correlation of A1 in honblende with pressure of solidification of calc-alkaline plutons,Am. Mineral., 1987, 72: 231.
Blundy, J. D., Holland, T. J. B., Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer,Contrib. Mineral Petrol., 1990, 104: 208.
Twiss, R. J., Variable sensitivity piezometric equations for dislocation density and subgrain diameter and their relevance to olivine and quartz,Mineral and Rock Deformation: Laboratory Studies, Am. Geophys. Union. Geophys. Monogr., 1986, 36: 247.
De Bresser, J. H. P., Intracrystalline deformadtion of calcite,Ph D. Thesis, Institut voor Aardwetenschappen der Rijksuniversiteit Utrecht, 1991, 191.
Author information
Authors and Affiliations
About this article
Cite this article
Lü, G., Chen, J., Liu, R. et al. The formation depth of coesitebearing eclogite, Dabie UHPM zone, China, modified by tectonooriginal additional hydrostatic pressure. Chin.Sci.Bull. 44, 398–411 (1999). https://doi.org/10.1007/BF02977876
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02977876