the post-rift unconformity as well as petrographic evidence (fine grained and vesicular textures) suggests that emplacement and crystallization of these tholeiitic melts was at or near the surface. An eight to tenthousand foot variation in present-day depth to these rocks does not reflect the initial variation in their original depth of emplacement. Variations in topography during emplacement caused the initial differences, especially for the extrusive rocks. Post-Middle Jurassic subsidence of the flanks of the Peninsular Arch has further changed the apparent relative depth of emplacement (or extrusion) of these tholeiitic rocks.
OI S.E. GEORGIA EMBAYMENT
EXALABAMA NA
Appr~oximate basin limits __. 0_WALTON F
N
025TAYLOR50 MILES
0 40 80 KILOMETERS
GULF 0
EXPLANATION
Synclinal axis
~. 
Anticlinal axis HARDEE ST.
ApFigure 3. Florida basement proxe-Middlmate bJurassic tectonic features.s S UT
10
LFL ID
BASIN
COLLIER
0 25 50 MILES
0 40 80 KILOMETERS 4d **f
Figure 3. Florida basement pre-Middle Jurassic tectonic features.
10