Page 4 - i1052-5173-26-10

The geology of Cuba: A brief overview and synthesis

M.A. Iturralde-Vinent, Cuban Academy of Sciences, Cuba, maivcu@ to the subduction of Proto-Caribbean passive margin sequences
gmail.com; A. García-Casco, Departamento de Mineralogía of the Caribeana terrane, an offshore protuberance of Yucatan.
y Petrología, Universidad de Granada, Fuentenueva s/n, 18002 This event formed strongly deformed high-pressure meta­
Granada, Spain; and Instituto Andaluz de Ciencias de la Tierra, sedimentary and metaigneous rocks at ca. 70 Ma, when the
CSIC-Universidad de Granada, Granada, Spain; Y. Rojas-Agramonte, Caribbean plate began to collide with North America. The colli-
Institut für Geowissenschaften, Johannes Gutenberg-Universität, sion, which included overriding of the ophiolitic and arc units
Becherweg 21 D-55099 Mainz, Germany; J.A. Proenza, Departament over both subducted and unsubducted passive margin sequences,
de Mineralogia, Petrologia i Geologia Aplicada Facultat de Geologia, also produced synorogenic basins and filled them, a process that
Universitat de Barcelona (UB), Martí i Franquès s/n, 08028 continued until ca. 40 Ma. This foldbelt was succeeded by local
Barcelona, Spain; J.B. Murphy, Department of Earth Sciences, St. uplift and subsidence to form late Eocene–Recent unconformable
Francis Xavier, P.O. Box 5000, Antigonish, Nova Scotia, B2G 2W5, post-orogenic continental basins.
Canada; and R.J. Stern, Geosciences Department, University of
Texas at Dallas, Richardson, Texas 75080 USA INTRODUCTION AND GEOLOGIC SETTING

ABSTRACT Cuba has had a very interesting geologic evolution. The island is
geographically very near the United States, but for political
Cuba is the largest island in the Greater Antilles, and its geology reasons, U.S. geoscientists have not been able to study it much. In
records three important episodes: (1) the Jurassic breakup of North this overview1, we highlight the geology of Cuba. Useful publica-
and South America (Pangea) and associated passive margin and tions on Cuban geology produced during the past quarter century
oceanic sedimentary and magmatic evolution; (2) the sedimentary, can be found in Ceballos Izquierdo and Iturralde-Vinent (2016).
magmatic, and metamorphic evolution of an intra-oceanic We hope that the improving political situation will increase mutu-
Cretaceous-Paleogene ophiolite-arc complex; and (3) the Paleogene ally beneficial interactions in the future. A few relevant geographic
“soft collision” and transfer of the NW Caribbean plate (and and demographic facts about Cuba are listed in Table 1.
Cuba) to the North American plate. Thick sequences of Jurassic-
Cretaceous strata (conglomerates, sandstones, limestones, dolo­ Cuba is the largest island in the Greater Antilles and has been
stones, shales) and interlayered basaltic rocks characterize passive part of the North American plate (NOAM) since late Eocene time.
margin sequences preserved in the Guaniguanico terrane (western It is separated from other Greater Antilles islands by the North
Cuba, related to the Mayan passive margin and the Gulf of
GSA TODAY | OCTOBER 2016 Mexico) and the Bahamas Platform borderlands (north of Cuba).
Passive margin deposition ceased in latest Cretaceous time, when
increasing relief of accreted (overriding) oceanic arc and ophiolite
complexes shed coarse sediments (olistostrome and flysch),
followed by carbonate deposition. Fragments of the intervening
oceanic lithosphere (Proto-Caribbean, connected to the Central
Atlantic) and fore- and back-arc oceanic lithosphere (Caribbean,
of Pacific origin) occur as tectonic fragments detached from the
ophiolitic units, including serpentinized harzburgites and dunites,
banded and isotropic gabbros, basalts (tholeiitic and fore-arc
basalts, locally with boninites) and Late Jurassic (Tithonian)
through Late Cretaceous (Coniacian and younger) oceanic sedi-
ments. Arc activity in the Cuban segment of the Greater Antilles
produced sedimentary, volcanic, and plutonic rocks during
Cretaceous times (ca. 135–70 Ma). A new arc developed in eastern
Cuba during Paleocene–middle Eocene times. Cuban arc
sequences include island-arc tholeiitic, calcalkaline, and alkaline
bimodal suites of volcanic and plutonic rocks. Remnants of Proto-
Caribbean oceanic lithosphere occur as exhumed mélange-
bearing eclogite-, blueschist-, and garnet-amphibolite-facies
tectonic blocks (oldest age ca. 120 Ma) within a serpentinite
matrix intercalated with, or at the base of, the overthrusted ophi-
olitic bodies. Cuban Cretaceous arc magmatic activity ended due

GSA Today, v. 26, no. 10, doi: 10.1130/GSATG296A.1.
1This article was written as a companion to the Pardee Symposium “Geologic Evolution of Cuba” presented at the 25–28 September 2016 GSA Annual Meeting.

4