A Cretaceous Desert-Playa Sedimentary System Controlled the Potash Formation in the Simao Basin

Objective The Simao Basin in Yunnan Province has developed Cretaceous evaporite-bearing clastic deposits, including the Mangang and Mengyejing Formations which were originally interpreted as fluvial and lacustrine deposits. The Mangang Fm. composed of well-rounded quartz sandstones, were commonly considered as the bottom part of the Mengyejing salt series. Dttring last decades,

High resolution continuous sedimentary records of Upper Cretaceous obtained from the continental drilling(SK-1) borehole in Songliao Basin:Sifangtai and Mingshui Formations

The Sifangtai and Mingshui formations were continuously cored in the SK-1 n borehole（China Cretaceous Continental Scientific Drilling-SongKe1-the north borehole）.The core is 767.96 m long,and the recovery is 94.7%.The ages of the formations range from middle Campanian to Danian.The sequence and process of lithology-lithofacies and cyclic stratigraphy were described in detail.Eight litho-types compose the Sifangtai Formation,and 15 litho-types compose the Mingshui Formation.Deposition was predominantly in meandering river and lacustrine environments,including 10 microfacies in the Sifangtai Formation and 15 microfacies in the Mingshui Formation.The complete sequence is composed of 535 m-scale cycles（sixth-order cycle）,152 fifth-order cycles,42 fourth-order cycles and five third-order cycles.The centimeter-scale description of the section revealed some previously unknown horizons such as a special type of mudstone,marl,volcanic ash and favorable sand reservoirs in the formations.The new-found evidence is very important for the interpretation of the evolution of the basin,conditions such as lake oxic events,the K/Pg boundary,tectonism in the late sag basin stage,and the reservoir-cap rock assemblages in the shallow stratigraphy.

Sedimentary characteristics and processes of the Paleogene Dainan Formation in the Gaoyou Depression, North Jiangsu Basin, eastern China

In this paper,the type,vertical evolution,and distribution pattern of sedimentary facies of the Paleogene Dainan Formation in the Gaoyou Depression of the North Jiangsu Basin are studied in detail.Results show that fan delta,delta,nearshore subaqueous fan,and lacustrine facies developed during the Dainan Formation period and their distribution pattern was mainly controlled by tectonics and paleogeography.The fan delta and nearshore subaqueous fan facies predominantly occur in the southern steep slope region where fault-induced subsidence is thought to have created substantial accommodation,whereas the delta facies are distributed on the northern gentle slope which is thought to have experienced less subsidence.Finally,the lacustrine facies is shown to have developed in the center of the depression,as well as on the flanks of the fan delta,delta,and nearshore subaqueous fan facies.Vertically,the Dainan Formation represents an integrated transgressiveregressive cycle,with the E2d1being the transgressive sequence and the E2d2being the regressive sequence.This distribution model of sedimentary facies plays an important role in predicting favorable reservoir belts for the Dainan Formation in the Gaoyou Depression and similar areas.In the Gaoyou Depression,sandstones of the subaqueous distributary channels in the fan delta and the subaqueous branch channels in the delta are characterized by physical properties favorable for reservoir formation.

Extensional Tectonics, Rifting, Formation of Sedimentary Basins, Cretaceous Volcanism, Emplacement of Dyke Swarms and Development of Hydrocarbon Pools: Case Studies from Peninsular India and Indian Ocean Region

Prolonged extensional regime in peninsular India resulted in formation of rift and grabens,elongated basins and Gondwana sedimentation along them.Downward progression of rift related faults caused decompression

Formation of the Devonian Fengtai Hydrothermal Brine Basin and the Metallogeny of Gold and Lead-Zinc Mineralizations in Shaanxi

The study of the relationships between the hydrothermal sedimentary formations and the gold and lead-zinc mineralizations in the Devonian Fengtai basin in Shaanxi shows that there was a hydrothermal brine sedimentary event which was inserted into the normal sedimentary background from the late Middle Devonian to the early Late Devonian. This event is closely related to gold and lead-zinc mineralizations in this area.

Hydrological Modeling of Aquifers and Their Ground Water Potentials: Implications for Water Resources Planning and Management in Parts of Obio/Akpor L.G.A, Rivers State, Nigeria

This study examined the hydrological modeling of aquifers and their ground water potentials for the purposes of water resources planning and management. This was done using the electrical resistivity method employing the schlumberger electrode configuration at randomly selected stations to obtain the thicknesses and resistivities of each layer and depth to the presumably conglomeratic sand stone and its resistivity. Findings showed that the top soil layer resistivity values vary from 59.3 to 248.4 ohm-m and thickness of 0.6 to 3.9 m. The second layer has resistivity values ranging from 45.0 to 743.5 ohm-m and a thickness range of 1.5 to 13.8 m. The wet sand is characterized by resistivity values ranging from 144.8 to 1930.2 ohm-m and a thickness range of 3.8 to 65.8 m. The conglomeratic sand/sand stone has resistivity values ranging from 55.8 to 7719.8 ohm-m. The depth to this bottom layer varies from 6.6 to 89.5 m. Findings indicate that the entire profile is a sedimentary formation represented by lithological units of sand and clayey sand which make for a good groundwater potentials. However, the groundwater potential zones of the study area in terms of transmisivity revealed four distinct classes representing “very good” (Mgbuosimini, Rumuigbo, Okporo, Rumuomasi and Rumuodara), “good” (Alakahia, Rumuodomaya, Oginigba and Rumuola), “moderate” (Aluu, Rumuekeni, Rumuokoro, Rumuobiakani and Rumueme), and “low” (Ogbogoro, Ozuoba, Akpajio, Elelenwo, Eliozu, Rumuepirikon, Rumuokwuta, Rumuebekwe and Rumurolu) groundwater potential in the area. Well logging should therefore be incorporated in borehole development process for safe and sustainable yield of groundwater in Obio/Akpor.