Sediment Characteristics And Provenance Of The Southern Zhaitang Island

As a result of the sea-level drop in the late Quaternary, the distribution of theglobal land and sea changed a lot. The studies to exhibit the marine sedimentscharacteristics, sedimentary process is an important means and basis for revealing thesources of sediments, the reason to change of sedimentary environment, change ofdistribution of land and sea and the modification of climate.The research area of thispaper is located in the southern of Zhaitang Island in Qingdao City, which belongs tothe Southern Yellow Sea continental shelf northwest of shallow sedimentary area.These samples were studied by several methods: grain size analysis, mineral analysis(heavy mineral s, clay minerals, detrital minerals), explanation of the high resolutionshallow seismic profile. The objects of study were which the sediments Cylindricalsamples(ZT1,ZT2) from the Southern Zhaitang Island. These samples were studied byseveral methods: grain size analysis, mineral analysis (heavy minerals, clay minerals,detrital minerals), explanation of the high resolution shallow seismic profile. Theresearch of the characteristic of sediments and sedimentary provenance ismulti-faceted, these samples were studied by several methods: grain size analysis,mineral analysis (heavy mineral s, clay minerals, detrital minerals), explanation of thehigh resolution shallow seismic profile. The paper Systematically analysed ofsedimentary features and material sources of sediments from study area, expoundedthat the different sedimentary environments and influencing factors resulted in thedifferent sedimentary characteristics.,and pointed out that the characteristic ofsediments is the original relict sediments.According to the characteristics of grain size and lithologic, we can do whatdividing the two drillings into the two layers. The first layer, the main sediment typeis clayey silt, gravelly and silty sand; sediments contain a large number of shell debrisand gravels. The second layer, the main sediment type is gravelly sand, sedimentscontain a large amount of gravels. The sediments in the core are proluvial, slope wash,and weathered products of poor and very poor storing, which is derved fromnear and situ source. The first layer, the sediments did not experience seriouslytransformation by modern marine, mixed a small amount marine sedimentary factorwhich are original relict sediments. The second layer, the sediments did not accept thedisturbance role of modern marine sedimentary, which is the original relict sediments.The main heavy minerals of sediments are unstable minerals (hornblende,epidote), flaky minerals, stable minerals (zircon, garnet, apatite, tourmaline, rutile),metallic minerals (ilmenite), authigenic minerals (glauconite) and so on. The amountof the four clay minerals in descending order is illite, kaolinite, chlorite and smectite.The abnormal high content of illite reflected the terrigenous characteristic; and theabnormal low content of smectite reflected the stronger hydrodynamicenviroment.The main detrital minerals of sediments are clay minerals, quartz,feldspar, calcite, and dolomite. The mineral analysis shows that the ratio of themineral content of the first layer is more stable than the second layer. It is reflectingthe first layer is the more complex sedimentary environment.The explanation of the high resolution shallow seismic profile shows thatbedrock depth is shallow in the study area. The structure of formation is simple type.The formation of research area was included bedrock and sediment layers. Thesediment layer is composed of incompact sediments, which is thin. According to thecharacteristics of reflection interface, we can do what dividing the two drillings intothe two layers. It corroborated conclusion is correct which is of sediment grain sizeand lithology. Due to the impact of external dynamic action, the first layer appearedwhat is loss or disappearance of the phenomenon in study area.The results of this thesis show that the main sediment is coarse-sediment of poorand very poor storing, which the characteristics of terrigenous sediments is obvious.The sediments which is derved from near and situ source, and affected by stronghydrodynamic environment. But the research area in later period, the sediments didnot experience seriously transformation by modern marine. That led to the researcharea existed the phenomenon of the sediments were imbalance wite modern marinedepositional environment. Therefore, this thesis infer that as a result of the sea level falling, and bare continental shelf turn into land, the sediments of research area isformed by weathered products. Later, the sediments experienced the effects of marinetransgression rapid, which formed the original relict sediments.