Plotted one-percentile and median values from grain-size analyses of 30 or more samples from all parts of a deposit of detrital tractive sediment fall into a linear arrangement which is defined as a CM pattern. The area of a complete CM pattern may be divided into sections which are related to sedimentary environments. The location of the plotted points for a single deposit within the area of a complete CM pattern indicates the probable conditions of transport and of deposition. Different conditions with identified characteristics include, for transport, uniform suspension, graded suspension, rolling, and turbidity flow, and for deposition, relative depth, wave action, and variation in slope. CM characteristics can be used in petroleum exploration to recognize sedimentary traps, and variations in environments of deposition with a single sedimentary basin, and thus, the favorability for the presence of petroleum deposits.