News Article | April 27, 2017
VANCOUVER, BC / ACCESSWIRE / April 27, 2017 / Vangold Resources Ltd. ("Vangold") (TSX-V: VAN) (OTC PINK: VNGRF) is pleased to announce the closing of its acquisition of a 100% interest in the El Pinguico Property and historic mine located 10 km from the City of Guanajuato, Mexico (the "Acquisition") - see news release dated January 05, 2017. Under the terms of the acquisition, Vangold has acquired 100% ownership of rights and title to the El Pinguico mining claims #166665 and #165491, totaling 71 hectares. Pursuant to the Acquisition, the Company has paid US$100,000 and issued 5,000,000 common shares to the vendors, Exploraciones Mineras Del Bajio, SA de CV (EMDB) and will issue 662,500 common shares as a finder fee. All securities issued will be subject to a hold period expiring August 27, 2017. Cameron King, President and CEO, of Vangold said, "I would like to take this opportunity to personally thank EMDB for their continuous support in working towards the closing and bringing this valuable asset into Vangold. Our shareholders have also provided the Company great support and confidence in our corporate strategy of purchasing undervalued silver and gold properties with a focus of unlocking the true potential of these assets through continuous exploration and mine development." Once one of Mexico's most prolific silver and gold mines with grades over 9 g/t Au and over 900 g/t Ag, with a 15 g/t Au eq. cutoff grade, as documented assays found in the detailed mine development plans performed between 1906 to 1910. Technical reports issued in 1907 by experts in the different areas (geology, mining, metallurgy and finance) provide documented evidence of the once profitable producer. [Prof. Robert T. Hill, 1910, Report upon the Properties of The Pinguico Mines Company, The Securities Corporation Ltd. NY, NY]. In 1913, due to the Mexican Revolution, the El Pinguico Mine ceased operations, leaving behind several hundred thousand tons of broken ore in the underground stopes and the unmined vein system continuing at depth and length. Through several gold and silver cycles since the turn of the Century, The Pinguico mine has been a point of discussion to be put back into production. In 1959, an extensive geological assessment was undertaken, assays grade average of 2.72 g/t Au and 251 g/t Ag were reported, with various samples throughout the underground stock pile showing grades over 5 g/t Au and 500 g/t Ag (CRM Mexican Geological Survey 1959, ESTUDIO GEOLOGICO MINERO DE LA ZONA "EL PINGUICO" DISTRITO MINERO DE GUANAJUATO, GTO, Authors: Ing. Edgardo Meave T., Ing. Juan M Gómez, Ing. José Nava Arrieta). Not until 2012 was there additional work conducted in the mine, a sizeable assay program and mine plan development was led by Exploraciones Mineras Del Bajio and undertaken by Servicio Geologico Mexicano - SGM (Mexican Geological Survey), showing a potential underground broken ore with average grades of 1.6 g/t of Au and 143 g/t of Ag. [SGM, 2012, Certificacion de Reservas Mineral Quebrado en la mina "El Carmen-El Pinguico" Municipio de Guanajuato, Gto. For qualifications and key assumptions, see the Company's news release dated January 5, 2017]. In February 2017, Vangold performed a similar assay program under 43-101 protocols, realized an 8% improvement in grade at 1.75g/t Au and 184 g/t Ag. Of specific interest, assays from the north end trench samples F-001 to F-005, of the underground stock pile, report a range of 3.78 g/t Au and 558 g/t Ag to 15.70 g/t Au and 1,475 g/t Ag. These results are attributed to fines falling from the exposed Dos Estrellas vein stope onto the stock pile (Vangold 43-101 Report Feb. 28, 2017, Carlos Cham QP, filed on SEDAR April 27, 2017). Table 13 Assay Results for 2017 Trench Samples (Samples Collected by the Author) from El Pinguico Underground Stockpile The potential of el Pinguico claims is important, where the main targets are to explore the lower Pinguico vein below the existing old workings. Also, the potential intersection of the Pinguico vein with the Mother Vein, which has been the most important ore source of the area, producing over a billion ounces of silver since 1500's. In addition of these 2 main targets, the exploration and understanding of the existing exposed veins such as the San Jose vein, Pachuca vein, el Pirul vein, La Joya vein, and el Pino vein have been targeted for immediate exploration programs. Vangold is a development stage silver and gold company focused on production in Mexico. Vangold is aggressively pursuing its business plan of becoming a producer through the development of its existing mineral property assets and the pursuit through acquisition of additional mineral assets which contribute to Vangold achieving its aggressive corporate growth objectives. The disclosure of historical, scientific or technical information regarding the Property in this news release has been reviewed and approved by Mr. Hernan Dorado Smith, Director. Mr. Dorado is a Qualified Person (QP) by the Mining and Metallurgical Society of America (MMSA) as defined in National Instrument 43-101 and has reviewed and approved the contents of the news releases. ON BEHALF OF THE BOARD OF VANGOLD RESOURCES LTD., This news release includes certain "Forward-Looking Statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995 and applicable Canadian securities laws. When used in this news release, the words "anticipate," "believe," "estimate," "expect," "target," "plan," "forecast," "may," "schedule," and similar words or expressions, identify forward-looking statements or information. These statements reflect the Company's current views with respect to future events and are necessarily based upon a number of assumptions and estimates that, while considered reasonable by the Company, are inherently subject to significant business, economic, competitive, political and social uncertainties and contingencies. Many factors, both known and unknown, could cause actual results, performance or achievements to be materially different from the results, performance or achievements that are or may be expressed or implied by such forward-looking statements or information and the Company has made assumptions and estimates based on or related to many of these factors. Investors are cautioned against attributing undue certainty to forward-looking statements or information. Although the Company has attempted to identify important factors that could cause actual results to differ materially, there may be other factors that cause results not to be anticipated, estimated or intended. The Company does not intend, and does not assume any obligation, to update these forward-looking statements or information to reflect changes in assumptions or changes in circumstances or any other events affecting such statements or information, other than as required by applicable law. None of the securities anticipated to be issued pursuant to the Arrangement have been or will be registered under the United States Securities Act of 1933, as amended (the "U.S. Securities Act"), or any state securities laws, and any securities issued in the Arrangement are anticipated to be issued in reliance upon available exemptions from registration requirements pursuant to Section 3(a) (10) of the U.S. Securities Act and applicable exemptions under state securities laws. This press release does not constitute an offer to sell or the solicitation of an offer to buy any securities.
Hackley P.C.,U.S. Geological Survey |
Araujo C.V.,Petrobras |
Borrego A.G.,CSIC - National Coal Institute |
Bouzinos A.,54 Energy |
And 27 more authors.
Marine and Petroleum Geology | Year: 2015
Vitrinite reflectance generally is considered the most robust thermal maturity parameter available for application to hydrocarbon exploration and petroleum system evaluation. However, until 2011 there was no standardized methodology available to provide guidelines for vitrinite reflectance measurements in shale. Efforts to correct this deficiency resulted in publication of ASTM D7708: Standard test method for microscopical determination of the reflectance of vitrinite dispersed in sedimentary rocks. In 2012-2013, an interlaboratory exercise was conducted to establish precision limits for the D7708 measurement technique. Six samples, representing a wide variety of shale, were tested in duplicate by 28 analysts in 22 laboratories from 14 countries. Samples ranged from immature to overmature (0.31-1.53% Ro), from organic-lean to organic-rich (1-22wt.% total organic carbon), and contained Type I (lacustrine), Type II (marine), and Type III (terrestrial) kerogens. Repeatability limits (maximum difference between valid repetitive results from same operator, same conditions) ranged from 0.03 to 0.11% absolute reflectance, whereas reproducibility limits (maximum difference between valid results obtained on same test material by different operators, different laboratories) ranged from 0.12 to 0.54% absolute reflectance. Repeatability and reproducibility limits degraded consistently with increasing maturity and decreasing organic content. However, samples with terrestrial kerogens (Type III) fell off this trend, showing improved levels of reproducibility due to higher vitrinite content and improved ease of identification. Operators did not consistently meet the reporting requirements of the test method, indicating that a common reporting template is required to improve data quality. The most difficult problem encountered was the petrographic distinction of solid bitumens and low-reflecting inert macerals from vitrinite when vitrinite occurred with reflectance ranges overlapping the other components. Discussion among participants suggested this problem could not be easily corrected via kerogen concentration or solvent extraction and is related to operator training and background. No statistical difference in mean reflectance was identified between participants reporting bitumen reflectance vs. vitrinite reflectance vs. a mixture of bitumen and vitrinite reflectance values, suggesting empirical conversion schemes should be treated with caution. Analysis of reproducibility limits obtained during this exercise in comparison to reproducibility limits from historical interlaboratory exercises suggests use of a common methodology (D7708) improves interlaboratory precision. Future work will investigate opportunities to improve reproducibility in high maturity, organic-lean shale varieties. © 2014 Elsevier Ltd.
Garcia-Alonso D.,Autonomous University of Nuevo León |
Garcia-Alonso D.,National Autonomous University of Mexico |
Canet C.,National Autonomous University of Mexico |
Gonzalez-Partida E.,National Autonomous University of Mexico |
And 5 more authors.
Journal of South American Earth Sciences | Year: 2011
In the San Marcos ranges of Cuatrociénegas, NE Mexico, several sediment-hosted copper deposits occur within the boundary between the Coahuila Block, a basement high mostly granitic in composition and Late Paleozoic to Triassic in age, and the Mesozoic Sabinas rift basin. This boundary is outlined by the regional-scale synsedimentary San Marcos Fault. At the basin scale, the copper mineralization occurs at the top of a ∼1000m thick red-bed succession (San Marcos Formation, Berrisian), a few meters below a conformable, transitional contact with micritic limestones (Cupido Formation, Hauterivian to Aptian). It consists of successive decimeter-thick roughly stratiform copper-rich horizons placed just above the red-beds, in a transitional unit of carbonaceous grey-beds grading to micritic limestones. The host rocks are fine- to medium-grained arkoses, with poorly sorted and subangular to subrounded grains. The detrital grains are cemented by quartz and minor calcite; besides, late iron oxide grain-coating cement occurs at the footwall unmineralized red-beds. The source area of the sediments, indicated by their modal composition, is an uplifted basement. The contents of SiO2 (40.70-87.50wt.%), Al2O3 (5.91-22.00wt.%), K2O (3.68-12.50wt.%), Na2O (0.03-2.03wt.%) and CaO (0.09-3.78wt.%) are within the ranges expected for arkoses. Major oxide ratios indicate that the sedimentary-tectonic setting was a passive margin. The outcropping copper mineralization essentially consists in a supergene assemblage of chrysocolla, malachite and azurite. All that remains of the primary mineralization are micron-sized chalcocite grains shielded by quartz cement. In addition, pyrite subhedral grains occur scattered throughout the copper-mineralized horizons. In these weathered orebodies copper contents range between 4.24 and 7.72. wt.%, silver between 5 and 92. ppm, and cobalt from 8 to 91. ppm. Microthermometric measurements of fluid inclusions in quartz and calcite crystals from footwall barren veinlets gave temperatures of homogenization between 98 °C and 165 °C, and ice-melting temperatures between -42.5 °C and -26.1 °C. The primary copper mineralization formed during the early diagenesis, contemporary with the active life of the Sabinas Basin. The mineralizing fluids were dense, near neutral, moderately oxidized brines that originally formed from seawater that, driven by gravity, infiltrated to the deepest parts of the basin and dissolved evaporites. As a result, they became hydrothermal fluids of moderate temperature capable of leaching high amounts of copper. The source of this metal could be mafic detrital grains and iron oxides of the underlying Jurassic and Lower Cretaceous red-beds. Copper precipitation took place when the brines passed through the redox boundary marked by the transition from red- to grey-beds. The upward movement of the brines was promoted by a high heat flow that allowed their convective circulation and their ascent along the synsedimentary San Marcos Fault. © 2011 Elsevier Ltd.
Villasenor A.B.,Institute Geologia |
Oloriz F.,University of Granada |
Lopez Palomino I.,Servicio Geologico Mexicano |
Lopez-Caballero I.,Sede Institute Geologia
Revue de Paleobiologie | Year: 2012
Ten years after the publication of "Recent advances in Upper Jurassic (Kimmeridgian-Tithonian) ammonite biostratigraphy of north-central Mexico, based on recently collected ammonite assemblages", a working program based on bed-by-bed sampling of upper Jurassic sections in Mexico has allowed to improve information about known and new outcrops in northeastern, central-eastern and south-eastern Mexico. The present contribution provides an updating of the obtained information, a part of which has been published elsewhere. Of special relevance are new data concerning Oxfordian and latest Kimmeridgian/earliest Tithonian ammonites from central-east and south-eastern Mexico, which are considered as preliminar information of prime importance for correlation. A re-evaluation of registered ammonite assemblages is made in terms of faunal - ammonite - horizons of three orders of relevance for biostratigraphic correlation in Mexico. They integrate within the ammonite assemblages formally proposed previously, and their biochronostratigraphic meaning is only tentatively approached due to the incidence of endemism.
Vogt M.,University of Heidelberg |
Stinnesbeck W.,University of Heidelberg |
Zell P.,University of Heidelberg |
Kober B.,University of Heidelberg |
And 7 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2016
Here we provide a detailed description of the upper Campanian sediment succession at Las Águilas, southern Coahuila, northeastern Mexico, including the first absolute age dating for this interval, paleoenvironmental reconstructions and taphonomic observations on the abundant dinosaur remains at the locality. Stratigraphic investigations of the dinosaur-bearing succession at the Las Águilas vertebrate fossil area near Porvenir de Jalpa reveal a diverse vertebrate assemblage, including dinosaurs, crocodilians and turtles. New findings in adjacent sites include eusuchian crocodylomorphs, four different kinds of turtles, dromaeosaurids, lambeosaurines, pterosaurs and elasmosaurid plesiosaurs. Strontium isotope measurements on fossil oyster shells provide an absolute age of 73 ± 1 Ma for the lower part of the Las Águilas section. The locality is thus of late Campanian age. The vertebrate, invertebrate and plant materials as well as the sediment structures observed in a 50 m thick predominantly siliciclastic succession of the Cerro del Pueblo Formation suggest deposition in an extensive delta plain environment. The facies succession indicates a short-termed cyclicity of limnic, brackish and shallow marine environments during the late Campanian-early Maastrichtian Cerro del Pueblo Formation with numerous layers containing dinosaur fossil remains. Resumen: Aquí damos una descripción detallada de la sucesión de sedimentos del Campaniano Superior en Las Águilas, sur de Coahuila, noreste de México, incluyendo la primera datación absoluta para este intervalo, reconstrucciones paleoambientales y observaciones taxonómicas sobre la abundancia de restos de dinosaurios en la localidad. Investigaciones estratigráficas de los estratos con dinosaurios en el área fosilífera de Las Águilas cerca de Porvenir de Jalpa revelan un ensamblaje vertebrado diverso, incluyendo dinosaurios, cocodrilos y tortugas. Nuevos descubrimientos en sitios adyacentes incluyen crocodylomorfos eusuquios, cuatro diferentes tipos de tortugas, dromaeosauridos, lambeosaurinos, pterosaurios, y plesiosaurios elasmosauridos. Mediciones de isótopos de estroncio en conchas de ostiones fósiles proveen una edad absoluta de 73 ± 1 millones de años para la parte inferior de la sección de Las Águilas. La localidad es por lo tanto de edad Campaniana tardía. El material de vertebrados, invertebrados y de plantas así como las estructuras sedimentarias observadas en una sucesión predominantemente siliciclástica de 50 m de la Formación Cerro del Pueblo sugieren una depositación en un ambiente de una extensa planicie deltáica. La sucesión de facies indica una ciclicidad de periodo corto de ambientes limnicos, estuarinos y marinos someros durante el Campaniano tardío-Maastrichtiano temprano de la Formación Cerro del Pueblo con numerosos estratos conteniendo fósiles de dinosaurios.Palabras Clave: Las Águilas, sucesión de dinosaurios, Campaniano superior, ambientes deposicionales, Formación Cerro del Pueblo, Coahuila. © 2015 Elsevier B.V.
Madhavaraju J.,National Autonomous University of Mexico |
Gonzalez-Leon C.M.,National Autonomous University of Mexico |
Lee Y.I.,Seoul National University |
Armstrong-Altrin J.S.,National Autonomous University of Mexico |
Reyes-Campero L.M.,Servicio Geologico Mexicano
Cretaceous Research | Year: 2010
The elemental content (major, trace and rare earth elements) of 35 Aptian-Albian limestone samples from the Mural Formation has been determined to provide information on depositional conditions and provenance. The limestones of the Mural Formation show large variations in terrigenous and carbonate contents (1.2 to 42.3% and 57.7 to 98.8% respectively). Small variations are observed in CaO concentrations in the Tuape Shale, Cerro La Puerta and Mesa Quemada members whereas large variations are found in the Cerro La Ceja, Los Coyotes and Cerro La Espina members. The majority of the limestones show high values of Th, Sc and Zr. Large variations in ΣREE content are observed among different members of the Mural Formation. Most limestones from the Mural Formation record non-seawater-like REE+Y signatures. The limestones show large variations in Ce anomalies which may be due to mixing of sediment components (biogenic and authigenic phases) and detrital materials including Fe-colloids from fluvial input. Most of the limestones show positive Eu anomalies, but some samples show negative Eu anomalies (Eu/Eu*: 0.42 to 2.62).The large variations in terrigenous percentage, high Al2O3 and ΣREE contents, high LaN/YbN ratios, low Y/Ho ratios and non-seawater-like REE patterns suggest that the observed variations in ΣREE contents are mainly controlled by the amount of detrital sediments in the limestones of the Mural Formation. The limestones of the Mural Formation were deposited under both coastal and open shelf environments, and they exhibit non-seawater-like REE+Y patterns. The presence of terrigenous materials in these carbonates as contaminants effectively masks the seawater signature due to their high concentration of the REE. Thus, trying to decipher the palaeoceanographic conditions represented by ancient carbonate rocks should be done cautiously since limestones deposited under open marine environments may also be contaminated by some amount of terrigenous particles. The presence of small quantities of terrigenous materials in the limestones can also reveal source rock information. The La/Sc, La/Co, Th/Sc, Th/Cr, Th/Co and Cr/Th ratios suggest that the terrigenous materials present in the limestones were mainly derived from a nearby exposed basement of intermediate to felsic igneous rocks. © 2010 Elsevier Ltd.
Geochemical homogeneity of hydrothermal alteration of the orogenic gold belt of NW Sonora, Mexico: Mass balance study in host rocks of the mineralization [Homogeneidad geoquímica de la alteración hidrotermal del cinturón de oro orogénico del NW de Sonora, México: Estudio de balance de masas en rocas encajonantes de la mineralización]
Izaguirre A.,National Autonomous University of Mexico |
Iriondo A.,National Autonomous University of Mexico |
Iriondo A.,University of Texas at Austin |
Caballero-Martinez J.A.,Servicio Geologico Mexicano |
And 2 more authors.
Boletin de la Sociedad Geologica Mexicana | Year: 2012
A geochemical mass balance study, combined with petrography, bivariate Au and Ag geochemical analysis, and inclusion study in pyrites and native gold, was performed on a suite of hydrothermally altered host rocks and contemporaneous quartz veins from the Caborca Orogenic Gold Belt in NW Sonora, Mexico (COOC; by its abbreviations in Spanish: Cinturón de Oro Orogénico Caborca). These combined studies helped evaluating the geochemical homogeneity of the mineralizing fluids that formed the alteration envelopes and the auriferous quartz veins in the entire area occupying the COOC (~400 km long and ~60-80 km wide belt). The isocon statistical technique used in the mass balance study was applied on 20 pairs of mayor and trace element geochemical data of altered and fresh rock samples. The results show that the majority (>50 %) of the altered host rocks are enriched in K 2O, W, Cu, Pb, Mo, Tl, Be, Zn, V, Sb, Ag, Sn, SiO 2, Se, Ni and FeO, and are clearly depleted in Ca, Y, Na, Ho, Co, Sr, Yb, Mn, Dy, Er and Tb. The similar pattern of enrichment and depletion was shown by most of the studied samples suggesting a high degree of geochemical homogeneity of the mineralizing fluids. Petrography on both the altered and fresh rocks indicates that the hydrothermal alteration primarily consisted of silicification, sericitization, chloritization, epidotization and pyritization. The bivariate Au and Ag geochemical studies, done in auriferous quartz veins, show a strong positive correlation between these two elements and the enriched elements shown by the mass balance study on the altered host rocks. Therefore, these elements could be utilized as a geochemical exploration guide to targeting orogenic gold deposits in the region. Multiple inclusions of native gold and silver, galena, covellite, sphalerite, molybdenite, scheelite and tourmaline were encapsulated in pyrite and native gold grains in the quartz veins. Presence of these mineral occurrences explains most of the elemental anomalies obtained geochemically on the quartz veins and altered host rocks. In conclusion, the geochemical homogeneity of the mineralizing fluid, proposed in this study, implies that the mineralization (Au-rich quartz veins) and associated alteration assemblages were part of a large-scale event synchronous with the Laramide orogeny when compressional tectonism was active during Late Cretaceous to Early Tertiary time.
Rosas-Elguera J.,University of Guadalajara |
Reyes B.A.,National Autonomous University of Mexico |
Goguitchaichvili A.,National Autonomous University of Mexico |
Rocha M.,Servicio Geologico Mexicano |
And 4 more authors.
Studia Geophysica et Geodaetica | Year: 2011
For long time the western-central Mexico has been affected by oblique subduction caused by Farallon plate beneath North America. As result, smaller plates (e.g. Cocos Plate), several fault systems outlining crustal blocks (e.g. Michoacán block) and magmatic arcs (e.g. Paleocene-Early Oligocene magmatism and the Trans-Mexican Volcanic Belt) were developed. Still, no paleomagnetic data are available for Oligocene and Miocene. The principal aim of this study is to evaluate whether the tectonic rotations and relative motions of these blocks occurred before the Miocene. Here, we report a detailed rock-magnetic and paleomagnetic results from Tecalitlan area, located in the Michoacán block. Sixteen sites (about 150 oriented samples) were collected including one radiometrically dated diabase dike (35.0 ± 1.8 Ma). Rock-magnetic experiments permitted identification of magnetic carriers and assessment of the paleomagnetic stability. Continuous susceptibility measurements vs temperature in most cases yield reasonably reversible curves with Curie points close to that of magnetite. Reliable paleomagnetic directions were obtained for 12 sites. Inclination I and declination D of the mean paleomagnetic direction obtained in this study are I = 33.1°, D = 345.0°, and Fisherian statistical parameters are k = 25, α95 = 8.9°. The corresponding mean paleomagnetic pole position is Plat = 75.7°, Plong = 166.6°, K = 31, A95 = 8.0°. The mean inclination is in reasonably good agreement with the expected value, as derived from reference poles for the stable North America. Magnetic declination is not significantly different from that expected which is in disagreement with a counterclockwise tectonic rotation of about 20° previously reported for the studied area. Based on paleomagnetic results obtained in this study compiled with those currently available from the Michoacán Block, we propose a simple model suggesting that sometime in Eocene epoch the convergence vector of the Farallon plate relative to North America plate was normal to the trench before reaching an actual oblique convergence. © 2011 Institute of Geophysics of the ASCR, v.v.i.
Characterization of the bisbee group (Lower cretaceous) south of the Basómari Range, northeastern Sonora, Mexico [Caracterización del Grupo Bisbee (Cretácico Inferior) en el área al sur de la sierra Basómari, Noreste de Sonora, México]
Monreal R.,University of Sonora |
Cano-Corona I.,Servicio Geologico Mexicano |
Grijalva-Noriega F.J.,University of Sonora |
Montijo-Gonzalez A.,University of Sonora |
Almazan-Vazquez E.,University of Sonora
Boletin de la Sociedad Geologica Mexicana | Year: 2011
The Bisbee Group is the most important lithostratigraphic unit that identifies the Lower Cretaceous in southeastern Arizona and northeastern Sonora. In the sierra Basómari, this group is characterized by outcrops of the Morita, Mural and Cintura formations, which are strongly affected by folds of kilometric dimensions locally overturned, normal faults of Mesozoic age, and a Cenozoic normal faulting. These lithostratigraphic units are overlain by Tertiary volcanic and sedimentary rocks. In the study area the Morita Formation is constituted by thin- to medium-bedded fine-grained sandstone, with some horizons with fossil wood, intercalated with fossiliferous and marly thin- to medium- bedded limestone. The Mural Limestone is characterized by thin- to massive-bedded fossiliferous limestone, intercalated with thin- to medium-bedded sandstone and clayish sandstone beds. The Cintura Formation is mainly made up of thin- to massive-bedded sandstone intercalated with laminar to thin-bedded mudstone. The Bisbee Group rocks in the area of the sierra Basómari represent shallow- marine sedimentary environments: intertidal inner neritic, middle neritic with development of lagoonal and ooidal bank conditions, outer neritic (open marine platform) and pelagic.