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Isla San Pedro Nolasco as a Late Miocene intrusive record at the eastern margin of the gulf of california:Insights from geological,geochemical and geochronological studies

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Geoscience Frontiers 2022年第3期13卷 100-114页

作者： L.A.Velderrain-Rojas J.R.Vidal-Solano L.M.Alva-Valdivia R.Vega-Granillo M.López-Martinez Departamento de Geología División de Ciencias Exactas y NaturalesUniversidad de SonoraC.P.83000 HermosilloSonoraMexico Laboratorio de Paleomagnetismo Instituto de GeofísicaUniversidad Nacional Autónoma de MéxicoCircuito de la Investigación CientíficaC.P.04510 MéxicoD.F.Mexico Departamento de Geología División de Ciencias de la TierraCentro de Investigación Científica y de Educación Superior de EnsenadaBaja CaliforniaMexico

Isla San Pedro Nolasco(ISPN)is a structural high bounded by inactive dextral oblique-slip faults in the east-central part of the gulf of california rift zone and is composed of intrusive rocks not exposed on other gulf of california islands.Here we present the reconnaissance results from geological mapping,as well as first geochemical and geochronological data for the ISPN intrusive complex.The intrusive rocks compose a sheet-like body of intermediate and felsic composition intruded by an intermediate and acidic dike swarm.All intrusive rocks(host and dikes)range in age from ca.9 Ma to 10 Ma(^(40)Ar/^(39)Ar)and show a hydrous ferromagnesian mineral association(amphibole and biotite)with a calc-alkalic and transitional affinity.This hydrated mineralogical association has not been recognized in the coeval rocks along the onshore western margin of the North American plate(coastal Sonora).However,such hydrous mineralogical association is found in the coeval rift transitional volcanic rocks from the Baja california Microplate at Santa Rosalía and Bahía de LosÁngeles–Bahía de LasÁnimas.The ISPN continental block,at least 40 km long,has been pulled apart by transtensional faulting of the late Miocene gulf of california shear zone before the westward migration of the North America-Pacific plate boundary at ca.3–2 Ma.Eventually,ISPN became isolated as an island during the late Miocene flooding of the gulf of california seaway.

关键词： PAC-NAM plate boundary gulf of california Intrusive rocks Isla San Pedro Nolasco

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Variability in the Light Absorption Coefficient by Phytoplankton,Non-Algal Particles and Colored Dissolved Organic Matter in the Northern gulf of california

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Open Journal of Marine Science 2018年第1期8卷 20-37页

作者： Stella P.Betancur-Turizo Adriana G.González-Silvera Eduardo Santamaría-Del-Angel Roberto Millán-Núnez Eduardo Millán-Núnez Héctor García-Nava Víctor M.Godínez Laura Sánchez-Velasco Facultad de Ciencias Marinas Universidad Autonoma de Baja CaliforniaEnsenadaMéxico Grupo de Investigacion en Oceanología Facultad de Oceanografía FísicaEscuela Naval de Cadetes“Almirante Padilla”Barrio BosqueSector ManzanilloCartagena de IndiasColombia Departamento de Ecología Marina CICESEEnsenadaMéxico Instituto de Investigaciones Oceanológicas Universidad Autónoma de Baja CaliforniaEnsenadaMéxico Departamento de Oceanografía Física CICESEEnsenadaMéxico Departamento de Plancton y Ecología Marina CICIMAR-IPN.Av.Instituto Politécnico Nacional s/nLa PazMéxico

Variability of the optical properties of the northern gulf of california (México) were analyzed for the first time based on six cruises performed from spring to summer (March to September) between 2008 and 2013. The changes observed in the absorption by three seawater components (phytoplankton, detritus and chromophoric dissolved organic matter or CDOM) were analyzed in relation to changes in bio-optical regions and composition of the phytoplankton community (determined based on phytoplankton pigments). Two regions with unique bio-optical characteristics were identified separated by a narrow transition zone: the Upper gulf of california (UGC) and Northern gulf of california (NGC). Despite the temporal changes in their spatial distribution they maintained particular characteristic. UGC is characterized by an average Chla of 1.78 mg/m3, the dominance of microphytoplankton (diatoms and dinoflagellates) and a stronger contribution of detritus to total light absorption. NGC is characterized by an average Chla of 0.7 mg/m3 and the predominance of picophytoplankton, characterized by the dominance of zeaxanthin (marker pigment for cyanobacteria) and/or chlorophyll b (marker pigment for green algae), along with a co-dominium by CDOM and phytoplankton to light absorption. Results indicate that Case II waters can be very different when evaluating the individual contribution by phytoplankton, detritus and CDOM to total light absorption what has to be considered for the selection of bio-optical models for each specific region what can also help to a better definition of the related uncertainties.

关键词： Light Absorption Phytoplankton CDOM Detritus Ocean Color gulf of california

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Comparing the biogeochemical functioning of two arid subtropical coastal lagoons:the effect of wastewater discharges

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Ecosystem Health and Sustainability 2021年第1期7卷 49-60页

作者： Julio Medina-Galván Carmen Cristina Osuna-Martínez Gustavo Padilla-Arredondo Martín Gabriel Frías-Espericueta Ramón Héctor Barraza-Guardado JoséAlfredo Arreola-Lizárraga Facultad de Ciencias del Mar Universidad Autónoma de SinaloaMazatlánMéxico Programa de Planeación Ambiental y Conservación Centro de Investigaciones Biológicas del NoroesteS.C.GuaymasMéxico Departamento de Investigaciones Científicas y Tecnológicas de la Universidad de Sonora HermosilloMéxico

Nutrient flux,net metabolism,and N2 fixation and denitrification processes were estimated and compared in two semi-arid subtropical coastal lagoons in the gulf of california:El Soldado(ES),where no wastewater is discharged,and El Rancho(ER),where shrimp farm effluents are regularly discharged.Biogeochemical processes were evaluated with the LOICZ model.Flushing time was<2 days in both systems.Nutrient fluxes were higher in ER than in ES and both systems acted as nutrient sinks for most of the year.ER showed a larger nutrient flow rate in the summer and autumn due to the input of shrimp-farm effluents.Nitrogen fluxes increased in both ER and ES in the winter in response to the increased nutrient supply from coastal upwellings.ER and ES both showed autotrophic metabolism and N2 fixation in the spring,autumn,and winter,but heterotrophic metabolism and denitrification in the summer.Denitrification dominated in ER(−2.21 mmol m^(2)day^(−1))and values were higher than those estimated in ES(−0.45 mmol m^(2)day^(−1)).The comparative analysis between ES and ER evidenced the significant changes in its biogeochemical performance caused by the input of anthropogenic nutrients,and can orient the environmental management of coastal lagoons.

关键词： Coastal lagoons nutrient budgets net ecosystem metabolism gulf of california

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The Disappearing Colorado River: Historic and Modern Attempts to Manage the Lifeline of the United States Southwest

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Open Journal of Soil Science 2021年第11期11卷 538-566页

作者： Kenneth R. Olson James M. Lang Department of Natural Resources Urbana Illinois USA Department of Crop Sciences College of Agricultural Consumer and Environmental Sciences University of Illinois Urbana Illinois USA

Historic Native American and modern civilizations have been forcing the unstable use of the Colorado River and adjacent land resources for centuries. Much can be learned from past Native American cultures that created irrigation systems to offset low rainfall. These lessons learned can be applied to our modern civilization. We can learn a lot from their previous behavior and experiences and could apply the lessons learned to our current disappearing Colorado River situation. Little of the Colorado River water flow reaches the international border with Mexico near Yuma, Arizona. Intensive consumption, mostly in the United States, has dried up the lower 160 km of the river. Since the 1960s, the Colorado River has rarely flowed into the gulf of california and when it does it becomes is a major international news event. The Colorado River Delta is drought prone and its headwater tributaries are a vital source of water for 40 million people. The Colorado River has whitewater rapids, canyons, and many United States National Parks. The tributary and river flow is managed by an extensive system of dams, aqueducts, and reservoirs. Most years the entire Colorado River flow is used for United States agricultural irrigation and domestic water supply purposes. The agricultural and urban needs in the United States are continuing to grow and it appears the days of Colorado River flowing into Mexico and the gulf of california are numbered and declining every decade. The Colorado River is disappearing and restoration efforts appear to be too little too late. If the Colorado River valley is ever going to recover management lessons and failures learned from the Native Americans, including the Hohokam, must be applied. A balanced approach to water management is needed and must include aggressive conservation and efficiency measures.

关键词： Grand Canyon Hohokam Mexico-American War gulf of california Salton Trough Hoover Dam Glen Canyon Dam

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