Sedimentary Stratigraphic Framework And Marine Geological Disasters In The Coastal And Offshore Yellow River Delta During The Late Quaternary

The Yellow River is cradle of Chinese nation and the Yellow River delta is a bright pearl studded in the Bohai Bay. With the quick development of the city of Dongying and the Shengli Oil Field, the contradiction between instability of Yellow River delta and stability demanded by industry and agriculture production even more evident. So the research as to Quaternary geology, geomorphy and marine geological disaster is increasingly important. In the last several years Quaternary sedimentary characteristic of Yellow River delta has been the hot issue for earth science field. A great many of drilling data has been indicated that there is intimate relationship between the sedimentary stratum and sea level variety. This represented stratum serial with alternate sea facies and land facies and unique sedimentary stratum framework. Because of frequent climatic sea level fluctuation in late Quaternary, complex shallow stratum framework at bed and retained and modern geomorphy folding formed. Therefore, it is the key point to mastering marine geological disaster to analyze thoroughly ancient environment evolvement and rule of space-time distribution of sedimentary geomorphy. And the analysis about factor types and distribution rules of disaster is to provide reliable evidence for preventing and reducing geological disaster in sub-littoral and littoral area, Yellow River delta. The research area is adjacent to estuary of Yellow River delta including land and sea. In the target area the east longitude is 118°30′~120°00′and the north latitude is 37°30′~38°30′with the land area 2800 km2 and the marine area 12500 km2. It has been an important means of dividing Quaternary stratum to analyzeshallow stratum profile. However, recent advances in the high-resolutionsequence stratigraphic concept result from large-scale subsurface and 3英文摘要outcrop studies of shallow-marine deposits in ancient epeiric seas. On theother hand, studies of high-resolution seismic profiles in modernepicontinental seas help understand depositional processes and stratalpatterns of Late Quaternary sediments that reflect high-frequency eustaticfluctuation in sea level. So the shallow stratigraphic seismic profile, havingbeen broadly applied to Quaternary sedimentary stratum, can' t be replacedwhen we analyze Quaternary stratum. Multi-subject integrating is an availablemeans of analyzing geological disaster. In this paper, according to the shallow stratum profile with 690km depth acquired from the bore HB-1, remote sensing image and water depth etc., systematic study is carried through about sedimentary stratum frame and geological disaster in Yellow River delta area. By means of interpreting shallow stratum profile with 690km depth, describing the core HB-1, granularity analyzing of core sample, identifying micropaleontology and measuring age of AMS C, the author classified the sedimentary stratum since 5 terms 14 oxygen isotope, studied the rule of its distribution. The author clarified stratum units and distribution characteristic since 5 terms oxygen isotope and reached the sedimentary facies and stratum depth since 3 terms oxygen isotope, that is, the deposit of 1 term oxygen isotope is about 20.79m forming since seawater come into Bohai after ice terms, the deposit of 2 term oxygen isotope is about 8.87 m land sediment deemed as the most prosperous during the last hypo-ice term, the deposit of 3 term oxygen isotope is about 30.35 m sea sediment belonging to the sub- ice term(about 25~58kaBP) of the last hypo-ice term. By means of analyzing shallow stratum profile, core, water depth and remote sensing, the author summarized the types distribution rules and reasons of marine geological disaster in the target area. It is indicated that the geological disaster includes coast corrosion, shallow layer gas, fault activity, bed land...