Range charts and no-space graphs

摘要: Abstract No-space graphs present one solution to the familiar problem: given data on occurrence of fossil taxa in separate, well-sampled sections, determine a range chart; that is, reasonable working hypothesis total area question each taxon studied. The presented here treats only relative sequence biostratigraphic events (first and last occurrences taxa) does not attempt an amount spacing between events. Relative hypothesized sequence, observed any section may be in-place or out-of-place. Out-of-place indicate (1) event reflects did fill its entire (unfilled-range event), (2) indicates need for revision sequence. A graph position (no-space graph) can used facilitate recognition out-of-place by presenting visual comparison observations from with geometry as constructed is such will lie along line series above below it. First-occurrence last-occurrence unfilled ranges. hypothesis. Knowing this, stratigrapher considers alternative positionings hypotheses seeks best fits his geologic paleontologic judgment. are revise initial until final reached. In this every found at least section, all sections interpreted represent unfilled-range No further revision. application no-space method requires assumption lack reworking single horizon whose ranges overlap. When applied hypothetical actual data, technique produces geologically charts compare favorably results produced other methods.