La Popa Basin

lovinggudgeonMechanics

Feb 22, 2014 (3 years and 3 months ago)

82 views

La Popa Basin

The significance of the La Popa basin lies in the accessibility of near salt deformation and
traps in surface

exposures, typically areas

of poor seismic image quality,
that can contain
large volumes of hydrocarbons in salt

basins.

The La Popa

basin, a small depocenter located in the foreland of the Sierra Madre
Oriental foldbelt in

northeastern Mexico, northwest of Monterrey, contains the most
complete exposures of Mesozoic and

Paleocene strata preserved in the foreland of the
Sierra Madre Ori
ental. The basin contains three elliptical

outcrops of gypsum
representing eroded salt stocks (“El Gordo”, “El Papalote” and “San José de la Popa”

diapirs) and a 25
-
km
-
long faultlike structure (“La Soldadura”) having intermittent
remnant gypsum that marks

an exposed subvertical salt weld. The basin formed during
Triassic

Jurassic rifting, as a pull
-
apart basin

associated on a strike
-
slip margin; postrift
subsidence resulted in widespread evaporite deposition during the

Oxfordian. From the
Late Jurassic into

the Late Cretaceous followed a period of shallow
-

to deep
-
water

carbonate deposition. During Upper Cretaceous to Middle Eocene, the basin was
dominated by a siliciclastic

succession, although lenticular carbonate strata (‘‘lentils’’)
were interbedded with

siliciclastic facies only

adjacent to the diapirs and weld.


Overview of the Monterrey


La Popa area (24.10


1
-
1: Huasteca canyon
-

introduction ; 1
-
2: Huasteca

canyon


last stop; 25.10


2
-
1: Potrero de García


salt cored anticline; 2
-
2:
southern fl
ank of Delgado

syncline


introduction to the La Popa stratigraphy; 2
-
3: center
of the Delgado syncline; 2
-
4: El Gordo

diapir


salt related carbonate lentiles; 26.10


3
-
1:
Potrero Chico


salt cored anticline; 3
-
2: El Papalote


near salt sedimentation a
nd deformation; 27.10


4
-
1: Boca de Carroza: La Popa salt weld;
4
-
2: San José

lentil


near salt weld sedimentation and deformation; 4
-
3: La Popa lentil


Eocene continental

sedimentation and salt weld; 4
-
4: boca de Potrerillos: SE end of the
weld).


Defo
rmation in the La Popa basin is a result of combined salt withdrawal/diapirism and
regional

contraction. Diapirism since Aptian can be documented from surface exposures
(Lawton et al., 2001),

shortening occurred during the latest Cretaceous to Eocene and w
as
accommodated primarily by salt
-
cored

detachment folding represented by the weld
(Rowan et al., 2003).

The field trip shows in several outcrops, phenomena related to passive diapirism of the
“El Gordo” and

“Papalote” diapirs, such as stratigraphic trappi
ng, near salt deformation,
and also structures as result of regional

contraction as the “La Popa weld”.