Fluvial Dominated Deltas
Rio Grande - LST 1

Lst 1 is interpreted as a fluvially-dominated delta based on the combination of lobate fan-mound geometry, the complex-sigmoid-oblique seismic pattern, and the lithologic information from the Rio Grande area. The lowstand unit is interpreted as consisting of a lowstand basin floor fan, a slope fan, and a lowstand wedge. The location of the basin floor fan is inferred from the geometry of the lowstand deposits and the location of the overlying slope fan. The location of the slope fan is mapped from the location of the parallel to subparallel reflection configuration on seismic line 24. There is no information from this dataset regarding the deposition of the basin floor fan and the slope fan. The location of the backstepping delta lobes corresponds to the change in reflection configuration from that interpreted as slope fan to a mounded onlap fill and chaotic pattern.

core data
seismic data


Main Characteristics
Width (km)
Length (km)
Thickness (ms) Shape Reflection
Lithology Subbottom
Depth (m)
95 x 65 ~ 230 fan
mound onlapping, chaotic
parallel, sub-parallel, divergent,
mounded onlapping, chaotic
top - ts
base - 2sb
SP-1, SP-2, SP-7 35-200

Depositional Interpretation
Interpretation Sediment
Volume (km3)
Timing (ybp) Deposition Rate
per 1000 yrs
Sea Level Eustatic vs
150 19,000
18.8 km3 rising eustatic

Sediment Yields
Volume = (4/3)*(Each isochron is divided into a series of spheroids whose volume is then summed (a * b* c, where a,b,c are radii).
total volume (km3) deposition timing sediment yield (km3)
per 10000 yrs
150.08 8000 18.76

Gulf Bottom Imagemap

Comments, questions? Contact us at gulf@gulf.rice.edu.