The Hurst statistic, converted easily into a fractal dimension, quantifies
the degree of clustering of high and low values in spatial or temporal seri
es of data. In an effort to better understand the stratigraphic organizatio
n of submarine-fan deposits, the Hurst statistic was calculated for ninetee
n turbidite sections that span a wide range of geological time, tectonic se
ttings, facies characteristics, and depositional environments. Three bed-by
-bed variables were considered: coarse-division thickness (i.e., net thickn
ess, in a single bed, of conglomerate + sandstone + siltstone), grain size,
and coarse division thickness percentage (relative to thickness of overlyi
ng mudstone caps). Sixteen of the 19 turbidite sections analyzed (84.2%) sh
ow the Hurst phenomenon, i.e., irregular, long-term clustering of high and
low values of the three bed-by-bed variables. This clustering is related to
stratigraphic changes of sedimentary facies caused by lateral shifting of
sub-environments on a submarine-fan surface. There is no evidence that the
clustering is controlled by sea-level fluctuations. The strength of the clu
stering, inferred from Hurst K values, holds promise as an index to disting
uish submarine-fan sub environments, Preliminary re suits suggest that chan
nel-levee deposits tend to have strong clustering; lobe-interlobe deposits
tend to display moderate clustering; and basin-floor sheet sand systems ten
d to have weak clustering. Combining facies characteristics with these stat
istical results provides more reliable criteria for the identification of s
ubmarine-fan sub-environments than are available from recently discredited
models based on asymmetric cycles of bed thickness or grain size.