We develop a model that describes the runout behavior and resulting de
posit of a radially spreading, suspension-driven gravity current on a
surface of negligible slope. Our analysis considers the separate cases
of constant-volume and constant-flux sources. It incorporates express
ions for the conservation of volume, a Froude number condition at the
current front, and the evolution of the driving suspension due to sett
ling of particles to the underlying bed. The mode! captures the key fe
atures of a range of experimental observations. The analysis also prov
ides important scaling relationships between the geometry of a deposit
and the source conditions for the deposit-forming flow, as well as ex
plicit expressions for flow speed and deposit thickness as functions o
f radial distance from the source. Among the results of our study we f
ind that, in the absence of information regarding flow history, the ge
ometries of relatively well-sorted deposits generated by flows with so
urce conditions of constant volume or constant flux are virtually indi
stinguishable. The results of our analysis can be used by geologists i
n the interpretation of some geologically important gravity-surge depo
sits. Using our analytical results, we consider three previously studi
ed, radially symmetric turbidites of the Hispaniola-Caicos basin in th
e western Atlantic Ocean, From gross geometry and grain size of the tu
rbidites alone we estimate for the respective deposit-forming events t
hat upon entry into the basin the initial sediment concentrations were
approximately 3% by volume and the total volumes were roughly between
30 km(3) and 100 km(3) Each of the suspension-driven flows is inferre
d to have spread into the basin with a characteristic speed of 3-5 m s
(-1), and reached its ultimate runout length of about 60-75 km while l
aying down a deposit over a period of about 10-12 hours.