Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
1
Mexican CordilleraMexican Cordillera
References:DNAG volume A, Ch. 9 Condie, K.C., 1993, Plate Tectonics and Crustal Evolution, pp. 266-269
Plate Evolution of Mexico Plate Evolution of Mexico and Caribbeanand Caribbean
� Separation of North America from Africa and South America
� Opening of the North Atlantic� Development of the Antilles arc� Growth of the Panama arc and Cayman
transform� Gulf of California opened; Hispaniola
and Puerto Rico moved eastward
Condie (1993)
North America, Africa, and South America were joined in Early Jurassic
Condie (1993)
North America began to rift in mid-Jurassic as North Atlantic opened
Condie (1993)
In Early Cretaceous the proto-Caribbean Basin opened
Condie (1993)
By Late Cretaceous spreading ended and Greater Antilles arc developed
2
Condie (1993)
In Early Tertiary Yucatan Basin and Cayman ridge transform developed
Condie (1993)
By Late Tertiary Panama arc grew & Gulf of California opened
Morphotectonic ProvincesMorphotectonic Provinces
� Pacific Ocean Floor
� Pacific Plate
� East Pacific Rise
� Rivera Plate
� Cocos Plate
East Pacific RiseEast Pacific Rise
� En echelon transforms in Gulf of California
� Depth of ~3,000 m
� Orozco FZ
� Spreading rate 9 cm/yr (E-W motion)
Rivera PlateRivera Plate� Rivera fracture
Zone
� Tamayo Fracture Zone
� Continental thrust
� 6 cm/yr plate motion S22E
� Convergence rate 2 cm/yr
3
� Middle American Trench� >5000 m deep� 6-7 cm/yr convergence
� Tehuantepec Fracture Zone
Cocos Cocos PlatePlate Gulf of CaliforniaGulf of California
� 1,200 km long and ~150 km wide
� Consists of 9 deep (4,00-5,000 m) basins
� Alluvial/marine fill of nearly 5,000 m
� M discontinuity at only 6 km depth
� ~500 km of rifting of Baja from Mexico
� Resulted from sea floor spreading and transform faulting that began in Late Miocene
Baja PeninsulaBaja Peninsula� Extends from Transverse Ranges to Cabo San
Lucas (1,450 km)� Three parts
� North: Peninsular Ranges� Middle: Sierra La Gigante volcanic plateau� South: Granite and metamorphic terrain
Sonoran Basin and RangeSonoran Basin and Range� Basement is 1.750 Ma schists, gneisses
and granites
� Youngest Proterozoic ~4 km thick quartzite and dolomite
� Paleozoic miogeocline ~2 km quartzite dolomite, limestone, sandstone.
� Mesozoic continental clastic and volcaniclastic sequences
Sierra Madre Sierra Madre OccidentalOccidental
� Volcanic Plateau 1,200 km long and ~ 3 km thick
� Lower volcanic complex ~ 100-45 Ma batholiths and associated extrusive rocks (andesites) 1,000 �1,400 m thick
� Upper volcanic supergroup ~34-27 Ma ignimbrites and calderas 600-800 m thick
Sierra Madre Sierra Madre OrientalOriental
� Folded and thrusted lower Cretaceous carbonates and upper Cretaceous flysch
� Only rare outcrops of older and deeper rocks
� High-level granitic stocks emplaced in the late Eocene
� Block faulting and some basic volcanism in the Miocene
4
Sierra Madre Sierra Madre del Surdel Sur
� ~ 1 Ga granulite basement similar to that of S.M. Oriental
� Acatlán Complex (~15 km) of west-dipping metamorphic rocks and ophilolites (Cam.-Dev.) sutured to the craton
Sierra Madre del Sierra Madre del SurSur
� Jurassic continental clastic rocks and volcanics
� Late Cretaceous-Eocene deformation similar to S.M. Oriental
� Early Tertiary continental sediments and Late Tertiary volcanic rocks (andesites).
Sierra de ChiapasSierra de Chiapas� Chiapas Massif -
Devonian batholith
� Upper Paleozoic deep marine sediments
Sierra de ChiapasSierra de Chiapas
� Triassic redbeds overlain by Cretaceous limestones
� Paleocene-Miocene ls, sh, ss (12,000 m)
� Early Miocene folding and thrusting towards SW
Trans Mexican Volcanic BeltTrans Mexican Volcanic Belt� East-West belt of Quaternary volcanoes
� High plateau (~2,300 masl)
� Stratovolcanoes & monogenetic volcanic fields
StratovolcanoesStratovolcanoes� Tepic� Colima� Ceboruco� Nevado de Toluca� Popocatépetl� La Malinche� Pico de Orizaba
5
Monogenetic Basaltic FieldsMonogenetic Basaltic Fields
� Michoacan-Guanajuato field
� Chichinautzin
� Scattered fields of basaltic cones and lavas