Study On Sedimentary Facies Of Late Devonian Famennian In Southern Margin Of Fitzroy Through In Canning Basin,Australia

The Canning Basin is one of the largest Paleozoic inland basins in Western Australia with long history of exploration and research,and it has abundant oil and gas resources.The Fitzroy Through is the most important part of the basin and receive extensive attention and in-depth study from the academic,especially there has been a clear understanding and rich research results of the marine carbonate deposition system of the northern margin of the Late Devonian Fitzroy Through.At the same time,the southern of the Late Devonian Fitzroy Through presents a complex clastic and carbonate mixed deposition system,and there is lack of uniform and recognized classification standard for the sedimentary facies,sequence stratigraphy,and sedimentary environment.This study analyze the sedimentary environment and evolution based on the sedimentary facies and sequence stratigraphic framework of Clanmeyer/Nullara Formation.The study mainly guided by the method and theory of petrology,sedimentology,sequence stratigraphy,well logging,seismic stratigraphy,combining core samples,drilling and seismic data,using core observation,analysis of rock microstructure,the joint analysis of seismic data to comprehensive analyze the study area from macroscopic to microscopic scale.As for this research,the southern margin of Fitzroy Through is comprised of Jurgurra and Barbwire Terrace,experienced complex tectonic deformation from Devonian to Upper Carboniferous.The thickness of the basin is controlled by the eustatic fall in sea level in the Famennian and series of synsedimentary faults.By a comprehensive analysis of contructing-sequence,Nullara Formation in the southern margin of Fitzroy Through during Fammenian is divided into 3 third-order sequences(SQ1?SQ2 and SQ3)in 1 second-order sequence.There are two types of sedimentary modles int the area: the clastic model named “Clanmeyer Formation” and the carbontates platform model named “Nullara Formation”.The clastics model mainly deceloped in the middle of the Jurgurra Terrace where is near the provenances.The face of Clanmeyer Formation is prodelta in SQ1 and SQ2 in early and middle Fammenian,and prograding delta front in late Famennian The sedimentary model of Nullara Formation is rimmed shelf platform.Sedimentary facies changes from restricted platform to open platform and reef then foreslope facies from east to west.No distinct changes from south to north due to the narrow width.