Landform reflecting current tectonic processes
| Feature |
Description |
Origin |
Age of Landform |
Image - Click to enlarge |
| Volcanic Arc |
Middle American Trench (MAT)
parallel volcanic landforms of Guatemala, El Salvador, and Nicaragua |
Cocos Plate subduction beneath
Caribbean Plate |
Pliocene (?) to Recent |
Chortis landforms reflecting
present tectonic setting |
| Median-Nicaragua Back-Arc
basin |
800 km long structural basin
and topographic low behind and parallel to MAT and volcanic arc from Salvador
to Nicaragua |
Active extension
-
subducted Cocos slab roll-back?
-
MAT not keeping pace with eastward movement of
Caribbean Plate?
|
Late Neogene (?) to Recent |
See above image |
| North-south trending ranges
and valleys of western Chortis |
Normal and strike-slip fault
bounded valleys and ranges west of Honduras Depression and north of back-arc. |
Caribbean-North American
Plate interaction across a diffuse margin.
Allowed by post-10 Ma deceleration of convergence
between South America and North America. |
Late Neogene to Recent |
See above image |
Landforms Reflecting Crustal Properties
of Chortis Block
| Feature |
Description |
Origin |
Age of landform |
Image - Click to enlarge |
| Elevated topographic/ bathymetric
portion
of Chortis Block |
All of Chortis block north of Median Nicaragua
back-arc |
Unknown.
Possibly a buoyant response. Implies lower crust - upper mantle
involvement.
|
Post - Middle Miocene.
Likely Late Neogene |
Elevated Portion of Chortis Block |
| West to East topographic/ bathymetric gradient. |
Higher elevations to west, north of back-arc. Includes
Eocene to recent sedimentation on Nicaragua Rise |
Crustal buoyancy variation across Chortis block
-
Continental crust west of GFS.
-
Transitional crust between GFS and Siuna, Nicaragua
-
Oceanic Crust east of Siuna, Nicaragua
|
Age of Crust
|
Cross-Chortis Block Elevation Gradient |
|
|
|
|
Crustal Types of Northern Central America |
Antecedent Landform Reflecting Paleotectonic
Processes and Differential Weathering of Rocks and Structures
| Feature |
Description |
Origin |
Age of landform |
Image - Click to enlarge |
| Patuca-Coco anticlinorium
(pre-Coco-Patuca rivers) |
Topographic feature that
separated alluvial Patuca and Coco rivers prior to entrenchment |
Exposure and differential
weathering of Montana de Colon fold-thrust belt |
Paleocene (?) |
Northeast Flowing Rivers of
Eastern Chortis Block |
| Northeast flowing meandering bedrock rivers of eastern
Chortis block |
Largest rivers on Chortis block (Patuca and Coco)
flow down topographic axis of Chortis block. |
River positions are pinned in place by uplift (see
below). River positions have NOT changed with eastward movement
of Chortis block. May reflect Maya block position to north. |
Miocene (?) |
See above image |
| Highlands of Chortis Block |
Ranges and relatively high
valleys (overprinted to west by extension) north of back-arc .
Includes meandering bedrock rivers, water
and wind gaps, and dissected erosion surfaces. |
Differential weathering of
rocks and structures subjected to epeirogenic uplift. Erosion accentuating
lithologic differences and fault systems. |
Post-Middle Miocene Padre
Miguel Group.
Probably late Neogene. |
Areas Displaying Evidence of Epeirogenic
Uplift |
| Bedrock Meanders and Canyons
"Boqueron" |
Fluvial meanders entrenched
>300 meters into bedrock. Contiguous in east, disrupted in west. |
Epeirogenic uplift of Chortis
block entrenched fluvial meanders. |
Post-Middle Miocene Padre
Miguel Group.
Probably late Neogene.
|
Meandering Bedrock Rivers |
| Fault bounded valleys of
the Guayape Fault System (GFS) |
Jamastran, Azucaulapa, Catacamas,
Culmi, and Paulaya valleys.
|
Pull-apart basins associated
with right slip on GFS. Jamastran pull-apart contains valley fill
of Padre Miguel clasts. (see below) |
Middle Miocene - Padre Miguel
Group time
Probably ended prior to back-arc development.
|
Guayape Fault System |
| Alignment of rivers along GFS |
Guayambre, Guayape, Tinto, Pataste, Paulaya Rivers |
Erosion of sheared rock along GFS. |
Post-Tpm. Probably late Neogene and post epeirogenic
uplift |
See above image |
| Cross-GFS topographic gradient |
Average elevation is 1000
meters higher to NW of GFS |
Up to northwest movement
associated with right slip on GFS |
Miocene |
Cross-GFS Gradient |
| Distribution of rock age
across Guayape Fault |
Younger rocks on the topographically
higher NW side and older rocks on SE side.
(note: area not colored in image are pre-Cretaceous
age. Coverage is only for Honduras) |
Earlier motion on GFS involved
up to SE movement and erosion of pre-Cretaceous strata. |
Unknown |
Rock Age Distribution Across GFS |
| Valle de Jamastran - Southern
Extent of GFS |
Structural basin filled with
clasts of eroded Padre Miguel tuff. Volcanic center at southern margin
of basin. |
Danli volcanic center buries
southern extent of pull-apart basin. SW source of valley filling
Padre Miguel tuff blocked by volcano. Volcano not significantly affected
by GFS. |
Valley - Post Middle Miocene
Padre Miguel Group
Danli volcanic center - Pliocene (?) |
Guayape Fault System at Valle de Jamastran |
