Vertical variationof theMiocene sandstone mineralogyin the Kutei Basinhas beenrecognizedbut the reasons for this remain unsaid. Deltaic-sandstone facies, parasequence sets, detrital mineralogy, and provenance of the uppermost Middle Miocene to the Upper Miocene stratain the Anamta and Amantu areas were analyzed using twenty-threewellsand selected composite 2D and 3D seismic lines. Taxon indicators were correlated to build bio-and litho-stratigraphic markers: M50, M65, M66, and M70. The mineralogy dataset wasderivedfromcoreandcuttings, whilethe detrital minerals were described,counted, normalized, and plottedin ternary diagrams.The four key markers were tied to the 3D-seismic data for seismic-stratigraphy analysis to observe the parasequences, systemtracts, andsequence boundaries that correspond to the fluctuated relative sea-level. Theparasequence sets are:(1) M65 aggradation and progradation, (2) M66 progradation, forced-regression, and back to another progradation,(3) M70 progradation, which interestinglydemonstrate the detrital-mineral groupings. Qt-F-L suggests agradualchange up to the younger age from subarkosetosublitharenite towards feldspathic-litharenitetolitharenite.Qp-Lv-Ls demonstrates the sourcewasderivedfromcollision-suture and folded-thrust belt. Qm-F-Lt diagram reveals the mature rocks with stable frameworks to the recycled-orogen provenance. The sediments maturity and stability are further confirmedby the Qm-P-K ternary chart.The most importantfinding is asignificant shift of the paleo-shelf edge duringthe forced regression, as itseparated the mineralogy composition of the M66 to the underlying M65parasequence sets.