The Dong Ho sedimentary formation consists of gravel, sand and sandstone, mudstone interbeded with asphalt layer or oil shale cropping out at Quang Ninh is considered as outcrop of petroleum potential source rock and correlated to source rock of the Cenozoic basins on the continental shelf of Southeast Asia. Geochemical investigation  of major and trace elements content variation from 14 typical samples selected from diferent layers leads to divide the Dong Ho formation into two parts: the lower part characterized by unclear variation while the upper part exposing a more clear trend. The paleoenvironmental proxy and the CIA, CIW, PIA and CPA indices of the Dong Ho formation revealed high weathering intensity. V/Ni and C/Cr s vary from 0.14 to 1.52; and from 0.02 to 0.52 respectively indicate to oxic depositional environment. The provenance of the Dong Ho sedimentary layers come from the recycling of sedimentary source rocks and deposited within freshwater lacustrine environment dominated with humid climate with estimated mean annual rainfall of 1533 mm / yr ± 181 mm before changing to wet and reductioin environment during diagenesis.

This paper aim to review currently four main approaches to paleoenvironment and paleoclimate research including: 1) paleotonlogy, 2) sedimentology, 3) major and trace element geochemistry, 4) stable isotopes. Sedimentary and geochemical proxies are widely used for many different sedimentary environments and ages. Paleontological proxies have limitation due to the poor preservation of fossil. The use of stable isotopes proxy to study paleo-environment and paleoclimate is new trend that can be applied to wide variety of subjects, from organisms to minerals sensitive to environmental change.               The environmental and paleoclimate information obtained from the above four approaches is not the same in terms of information type and level of detail. Paleontology only provides general information on the geographical conditions such as the continental environment, shallow seas, deep seas and continental shelves without detail on the environmental characteristics. Sedimentary records are likely to provide more detail on environmental and geographical information than paleontology proxies. The geochemical proxies provide information related to redox, humid or arid condition, high or less precipitation. Stable isotope provides the most quantitative approach compared to the others. The information obtained from this approach is based primarily on oxygen and carbon isotopes to reconstruct the history of temperature changes in the ocean and atmospheric environment. The quantitative level of the information obtained is gradually increased from the palaeontological, sedimentary, geochemical to stable isotope proxy. There is no unique optimal approach to paleo-environmental and paleo-climate research, therefore, in order to get a detailed and quantifiable information it is required to apply synchronously all four approaches mentioned above.