Holographic Stratigraphy of the Continental-shelf Deltas in Graben Basins
Holostratigraphic research of continental-shelf deltas in graben basins needs to be further studied.Taking a typical foreign continental-shelf delta as an example,based on the classic sequence stratigraphic theory,combined with the seismic reflection termination relationship,the third-order sequence and system tract were identified and divided,and the sequence stratigraphic framework was established.Based on cyclostratigraphy,the Milankovitch cycles within the gamma-ray curve of the drilling were identified by wavelet transformation,spectral analysis and inverse Fourier transformation filtering,and the absolute astronomical time scale was established by combining the geological-time reference point.The holographic stratigraphic framework was established by integrating chronostratigraphy,lithostratigraphy,magnetic stratigraphy,sequence stratigraphy,cyclostratigraphy and seismic stratigraphy,and the methodology and suggestion for dating the sequence boundary of continental-shelf deltas in graben basins were proposed.The results show that Neogene strata can be divided into 5 third-order sequences and 15 individual system tracts.Taking 23.03 Ma as the reference point,the absolute geological ages of the top boundary of CS1,CS2 and CS3 sequences are 13.93,9.13 and 2.13 Ma,respectively,and the absolute geological ages of their corresponding maximum flooding surface are 20.03,12.13 and 6.13 Ma,respectively.Aiming at the characteristics of progradation and lateral growth of continental-shelf deltas during the thermal depression period of graben basins,holographic stratigraphic research suggests that the geological age of the truncated top surface can be calculated by using the cyclostratigraphy of the drilling under the constraint of sequence framework in combination with magnetic stratigraphic dating and global sea level curve.If the outcome is basically consistent with the age of magnetic stratigraphy,the oblique sequence interface closest to the truncated top surface of the drilling may represent the true isochronous surface.
万方数据
维普
