Geology, age and tectonic evolution of the Sierra Maestra Mountains, southeastern Cuba

We summarize the available geological information on the Sierra Maestra Mountains in southeastern Cuba and report new zircon fission track and biotite Ar-Ar ages for this region. Two different and genetically unrelated volcanic arc sequences occur in the Sierra Maestra, one Cretaceous in age (pre-Maastrichtian) and restricted to a few outcrops on the southern coast, and the other Palaeogene in age, forming the main expression of the mountain range. These two sequences are overlain by middle to late Eocene siliciclastic, carbonatic and terrigenous rocks as well as by late Miocene to Quaternary deposits exposed on the southern flank of the mountain range. These rocks are britle deformed and contain extension gashes filled with calcite and karst material. The Palaeogene volcanic arc successions were intruded by calc-alkaline, low- to medium-K tonalites and trondhjemites during the final stages of subduction and subsequent collision of the Caribbean oceanic plate with the North American continental plate. U-Pb SHRIMP single zircon dating of five granitoid plutons yielded 206Pb/238U emplacement ages between 60.5 ± 2.2 and 48.3 ± 0.5 Ma. These granitoids were emplaced at pressures ranging from 1.8 to 3.0 kbar, corresponding to depths of ca. 4.5-8 km. 40Ar/39Ar dating of two biotite concentrates yielded ages of 50 ± 2 and 54 ± 4 Ma, indicating cooling through ca. 300 ºC. Zircon and apatite fission track ages range from 32 ± 3 to 46 ± 4 Ma and 31 ± 10 to 44 ± 13 Ma, respectively, and date cooling through 250 ± 50 ºC and 110 ± 20 ºC. The granitoids are the result of subduction-related magmatism and have geochemical characteristics similar to those of magmas from intra-oceanic island-arcs such as the Izu Bonin-Mariana arc and the New Britain island arc. Major and trace element patterns suggest evolution of these rocks from a single magmatic source. Geochemical features characterize these rocks as typical subduction-related granitoids as found worldwide in intra-oceanic arcs, and they probably formed through fractional crystallization of mantlederived low- to medium-K basalts. Several distinct phases of deformation were recognized in the Sierra Maestra, labelled D1 to D6, which define the transition from collision of the Palaeogene island arc to the formation of the Oriente Transform Wrench Corridor south of Cuba and later movement of the Caribbean plate against the North American plate. The first phase (D1) is related to the intrusion of a set of extensive subparallel, N-trending subvertical basalt-andesite dykes, probably during the early to middle Eocene. Between the late-middle Eocene and early Oligocene (D2), rocks of the Sierra Maestra were deformed by approximately east-west trending folds and north-vergent thrust faults. This deformation (D2) was linked to a shift in the stress regime of the Caribbean plate from mainly NNE-SSW to E-W. This shift in plate motion caused the abandonment of the Nipe-Guacanayabo fault system in the early Oligocene and initiation of a deformation front to the south where the Oriente Transform Wrench corridor is now located. Compressive structures were overprinted by widespread extensional structures (D3), mainly faults with southward-directed normal displacement in the Oligocene to early Miocene. During this period the plate boundary jumped to the Oriente fault. This event was followed by transpressive and transtensive structures (D4-D6) due to further development of the sinistral E-trending Oriente Transform wrench corridor. These structures are consistent with oblique convergence in a wide zone of left-lateral shear along an E-W-oriented transform fault

The geology of Cuba: A brief overview and synthesis

Cuba is the largest island in the Greater Antilles, and its geology records three important episodes: (1) the Jurassic breakup of North and South America (Pangea) and associated passive margin and oceanic sedimentary and magmatic evolution; (2) the sedimentary, magmatic, and metamorphic evolution of an intra-oceanic Cretaceous-Paleogene ophiolite-arc complex; and (3) the Paleogene 'soft collision' and transfer of the NW Caribbean plate (and Cuba) to the North American plate. Thick sequences of Jurassic-Cretaceous strata (conglomerates, sandstones, limestones, dolo­stones, shales) and interlayered basaltic rocks characterize passive margin sequences preserved in the Guaniguanico terrane (western Cuba, related to the Mayan passive margin and the Gulf of 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 sediments. 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 ophiolitic bodies. Cuban Cretaceous arc magmatic activity ended due to the subduction of Proto-Caribbean passive margin sequences of the Caribeana terrane, an offshore protuberance of Yucatan. This event formed strongly deformed high-pressure meta­sedimentary and metaigneous rocks at ca. 70 Ma, when the Caribbean plate began to collide with North America. The collision, which included overriding of the ophiolitic and arc units over both subducted and unsubducted passive margin sequences, also produced synorogenic basins and filled them, a process that continued until ca. 40 Ma. This foldbelt was succeeded by local uplift and subsidence to form late Eocene-Recent unconformable post-orogenic continental basins

Better than DEET Repellent Compounds Derived from Coconut Oil

Hematophagous arthropods are capable of transmitting human and animal pathogens worldwide. Vector-borne diseases account for 17% of all infectious diseases resulting in 700,000 human deaths annually. Repellents are a primary tool for reducing the impact of biting arthropods on humans and animals. N,N-Diethyl-meta-toluamide (DEET), the most effective and long-lasting repellent currently available commercially, has long been considered the gold standard in insect repellents, but with reported human health issues, particularly for infants and pregnant women. In the present study, we report fatty acids derived from coconut oil which are novel, inexpensive and highly efficacious repellant compounds. These coconut fatty acids are active against a broad array of blood-sucking arthropods including biting flies, ticks, bed bugs and mosquitoes. The medium-chain length fatty acids from C8:0 to C12:0 were found to exhibit the predominant repellent activity. In laboratory bioassays, these fatty acids repelled biting flies and bed bugs for two weeks after application, and ticks for one week. Repellency was stronger and with longer residual activity than that of DEET. In addition, repellency was also found against mosquitoes. An aqueous starch-based formulation containing natural coconut fatty acids was also prepared and shown to protect pastured cattle from biting flies up to 96-hours in the hot summer, which, to our knowledge, is the longest protection provided by a natural repellent product studied to date

Assessment of Yellow Fever Epidemic Risk: An Original Multi-criteria Modeling Approach

This article describes the use of an original modeling approach to assess the risk of yellow fever (YF) epidemics. YF is a viral hemorrhagic fever responsible in past centuries for devastating outbreaks. Since the 1930s, a vaccine has been available that protects the individual for at least 10 years, if not for life. However, immunization of populations in African countries was gradually discontinued after the 1960s. With the decrease in immunity against YF in African populations the disease reemerged in the 1980s. In 2005, WHO, UNICEF, and the GAVI Alliance decided to support preventive vaccination of at-risk populations in West African endemic countries in order to tackle the reemergence of YF and reduce the risk of urban YF outbreaks. Financial resources were made available to scale up a global YF vaccine stockpile and to support countries with limited resources in the management of preventive vaccination campaigns. This article describes the process we used to determine the most at-risk populations using a mathematical model to prioritize targeted immunization campaigns. We believe that this approach could be useful for other diseases for which decision making process is difficult because of limited data availability, complex risk variables, and a need for rapid decisions and implementation

Pyrethroid resistance alters the blood-feeding behavior in Puerto Rican <i>Aedes aegypti</i> mosquitoes exposed to treated fabric

<div><p>Emerging insecticide resistance is a major issue for vector control. It decreases the effectiveness of insecticides, thereby requiring greater quantities for comparable control with a net increase in risk of disease resurgence, product cost, and damage risk to the ecosystem. Pyrethroid resistance has been documented in Puerto Rican populations of <i>Aedes aegypti</i> (L.) mosquitoes. In this study, topical toxicity of five insecticides (permethrin, etofenprox, deltamethrin, DDT, transfluthrin) was determined for susceptible (Orlando—ORL) and resistant (Puerto Rico—PR) strains of <i>Ae</i>. <i>aegypti</i>. Resistance ratios were calculated using LD₅₀ values, and high resistance ratios for permethrin (112) and etofenprox (228) were observed for the Puerto Rico strain. Behavioral differences in blood-feeding activity for pyrethroid-resistant and pyrethroid-susceptible strains of <i>Ae</i>. <i>aegypti</i> when exposed to pyrethroid-treated cloth were also explored. Strains were exposed for 15 min to a range of concentrations of pyrethroid-treated uniform fabric in a cage that contained 60 female <i>Ae</i>. <i>aegypti</i> mosquitoes. Interestingly, the resistance ratios for blood-feeding were similar for permethrin (61) and etofenprox (70), but were lower than their respective resistance ratios for topical toxicity, suggesting that knockdown resistance was the primary mechanism of resistance in the blood feeding assays. Results showed a rightward shift in the dose-response curves for blood-feeding that indicated higher concentrations of pyrethroids were necessary to deter blood-feeding behavior in the pyrethroid-resistant Puerto Rican strain of <i>Ae</i>. <i>aegypti</i>.</p></div

Example of blood-feeding assay with untreated control (A) and permethrin-treated uniforms (B) inserted into a stock cage filled with approximately 60 female <i>Ae</i>. <i>aegypti</i> mosquitoes.

<p>Photos by G. Allen.</p

Topical LD₅₀, blood-feeding ED₅₀, and resistance ratios (RR) for ORL and PR <i>Ae</i>. <i>aegypti</i> strains tested with five insecticides.

<p>Blood-feeding data for transfluthrin are omitted because it had slope factors not significantly different from zero.</p

Review of Geochronologic and Geochemical Data of the Greater Antilles Volcanic Arc and Implications for the Evolution of Oceanic Arcs

The Greater Antilles islands of Cuba, Hispaniola, Puerto Rico and Jamaica plus the Virgin Islands host fragments of the fossil convergent margin that records Cretaceous subduction (operated for about 90 m.y.) of the American plates beneath the Caribbean plate and ensuing arc-continent collision in Late Cretaceous-Eocene time. The “soft” collision between the Greater Antilles Arc (GAA) and the Bahamas platform (and the margin of the Maya Block in western Cuba) preserved much of the convergent margin. This fossil geosystem represents an excellent natural laboratory for studying the formation and evolution of an intra-oceanic convergent margin. We compiled geochronologic (664 ages) and geochemical data (more than 1,500 analyses) for GAA igneous and metamorphic rocks. The data was classified with a simple fourfold subdivision: fore-arc mélange, fore-arc ophiolite, magmatic arc, and retro-arc to inspect the evolution of GAA through its entire lifespan. The onset of subduction recorded by fore-arc units, together with the oldest magmatic arc sequence shows that the GAA started in Early Cretaceous time and ceased in Paleogene time. The arc was locally affected (retro-arc region in Hispaniola) by the Caribbean Large Igneous Province (CLIP) in Early Cretaceous and strongly in Late Cretaceous time. Despite multiple biases in the database presented here, this work is intended to help overcome some of the obstacles and motivate systematic study of the GAA. Our results encourage exploration of offshore regions, especially in the east where the forearc is submerged. Offshore explorations are also encouraged in the south, to investigate relations with the CLIP.The authors greatly appreciate Javier Escuder Viruete and two anonymous reviewers with many constructive suggestions that helped we improve the manuscript. Haoyu Hu acknowledges support by Federal State Funding at Kiel University while Yamirka Rojas‐Agramonte acknowledges support by the Deutsche Forschungsgemeinschaft (DFG) grant RO4174/3‐3 and Antonio Garcia‐Casco acknowledges support by the Agencia Estatal de Investigación (AEI) grant MICINN PID2019‐105625RB‐C21. This is UTD Geosciences contribution #1682. Open access funding enabled and organized by Projekt DEAL

Dose response curves for blood-feeding behavior on permethrin-, etofenprox-, deltamethrin-, and DDT-treated uniforms with <i>Ae</i>. <i>aegypti</i> mosquitoes of the susceptible Orlando (ORL) strain (A) and pyrethroid-resistant Puerto Rico (PR) strain (B).

<p>The axes indicate the relationship between percent bite protection (right y-axis) and the log of the concentration in milligram per centimeter squared (x-axis) of insecticide-treated fabric. The left y-axis has been converted to a probit scale for clearer presentation. Error bars indicate SEM.</p

Review of Geochronologic and Geochemical Data of the Greater Antilles Volcanic Arc and Implications for the Evolution of Oceanic Arcs

Abstract The Greater Antilles islands of Cuba, Hispaniola, Puerto Rico and Jamaica plus the Virgin Islands host fragments of the fossil convergent margin that records Cretaceous subduction (operated for about 90 m.y.) of the American plates beneath the Caribbean plate and ensuing arc‐continent collision in Late Cretaceous‐Eocene time. The “soft” collision between the Greater Antilles Arc (GAA) and the Bahamas platform (and the margin of the Maya Block in western Cuba) preserved much of the convergent margin. This fossil geosystem represents an excellent natural laboratory for studying the formation and evolution of an intra‐oceanic convergent margin. We compiled geochronologic (664 ages) and geochemical data (more than 1,500 analyses) for GAA igneous and metamorphic rocks. The data was classified with a simple fourfold subdivision: fore‐arc mélange, fore‐arc ophiolite, magmatic arc, and retro‐arc to inspect the evolution of GAA through its entire lifespan. The onset of subduction recorded by fore‐arc units, together with the oldest magmatic arc sequence shows that the GAA started in Early Cretaceous time and ceased in Paleogene time. The arc was locally affected (retro‐arc region in Hispaniola) by the Caribbean Large Igneous Province (CLIP) in Early Cretaceous and strongly in Late Cretaceous time. Despite multiple biases in the database presented here, this work is intended to help overcome some of the obstacles and motivate systematic study of the GAA. Our results encourage exploration of offshore regions, especially in the east where the forearc is submerged. Offshore explorations are also encouraged in the south, to investigate relations with the CLIP