Calculating methods and assessment of stretching factor：A case study of Northern Jiangsu Basin

Basin stretching factor is a key parameter of extensional basin study and it was normally calculated from definition,balanced cross-section and tectonic-thermal modeling.The principles of traditional methods were briefly introduced in this paper,and the stretching factor of extension rifting in the Northern Jiangsu Basin after the late Cretaceous was also calculated.Basin stretching factor can be acquired by definition based on crust thickness,and it can be easily compared in different regions.For multi-phases stretch basin,it is hard to determine the stretching factor in different phases.The balanced cross-section method can reconstruct the basin stretching factor of multi-phases stretch,but the real equilibrium is actually hard to reach while the tectonic-thermal subsidence of the lower crust is not taken into consideration,thus other methods are needed for better comparison.The tectonic-thermal modeling method considers tectonic-thermal subsidence,and can also read curst thickness in any period.As a result,the tectonic-thermal modeling method is regarded as the more precise and convenient approach to calculate basin stretching factor.