重力和构造力在地壳中的作用

本文对于“上覆岩石重力数值等同于静水压力数值”的认识提出了新的看法，地壳中应力场Ｔ可以看成是一个静水压力Ｐ和一个差应力σ的复合、则静水压力Ｐ是由重力附加静水压力ＰＲ和构造力附加静水压力ＰＳ两者叠合而成，而不仅仅是来自上覆岩石的总重量，有限元模型计算表明，在同样外力条件下，从挤压变形带，剪切变形带到引张变形带中的各带构造附加静水压力值呈降低变化，即ＰＣ〉ＰＺｈ〉Ｐｔ，因而构造附加静水压力得造成局部静

ON THE ACTION OF GRAVITY AND TECTONIC STRESS IN EARTH CRUST

This paper argues against the knowledge that hydrostatic pressure is equal to the gravity value of the overlying rocks in studying a dynamic state of certain underground site, and discusses the influence of tectonic stress on hydrostatic pressure and its application.The research of solid mechanics and data from deep drillings indicated that gravity and tectonic stress in middle and shallow crust are directional external forces, whereas hydrostatic pressure is a force of non-directionless, so they possess different physical meanings. Gravity is not quantitatively equal to hydrostatic pressure either. During 108a- 106a of stress relaxation, the directional force on solild rock of the crust produces a deviatoric stress field.The authors suggest that stress field T of the crust is a combination or superposition of hydrostatic pressure P with differential stress a, and the total hydrostatic pressure P at any point in the crust comprises two parts, one is spherical stress tensor PR caused by the gravity and the other is spherical stress tensor Ps caused by tectonic stress, therefore P is not only from the gravity of overlying rocks.The results obtained by a finite element simulation indicate that the additional hydrostatic pressures borne by rocks decrease gradually from the compressive zone (P) to the shear zone (P) and to the tensile zone (P), i. e; and the difference of the tectonic additional hydrostatic pressure between these deformed zones trends to Increase, following the increase in absolute value and/or difference of external forces in different directions. So the tectonic additional hydrostatic pressre is a major factor causing the heterogeneity of local stress field in the same depth of the crust.The above-mentioned research has a wide-range of application= 1) to set up a model of unequal hydrostatic pressures in same depth of the crust; 2) to establish the method of measurement of metallogenetic depth corrected by structure, i. e., firstly minute toctonic added hydrostatic pressure P. from general hydrostatic pressute P, then measure and calculate thedepth data of overlying rocks; 3 ) to get Into a new research field of tectonic physicochemlstry; 4) reconsider the depth of eclogite in superhigh pressure metamorphic zone, such as the knowledge that the diamond and coesite in Dabie tectonic-metamorphic zone are probably the products of the inner crust; and 5) to introduce some new ideas about experiments of chemical kinetics.