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The largemouth bass (Micropterus salmoides) were fed diets with three experimental feeds, a control diet (Control, crude protein (CP): 54.52%, crude lipid (CL): 11.45%), a low-protein diet with lysophospholipid (LP-Ly, CP: 52.46%, CL: 11.36%), and a low-lipid diet with lysophospholipid (LL-Ly, CP: 54.43%, CL: 10.19%), respectively. The LP-Ly and LL-Ly groups represented the addition of 1 g/kg of lysophospholipids in the low-protein and low-lipid groups, respectively. After a 64-day feeding trial, the experimental results showed that the growth performance, hepatosomatic index, and viscerosomatic index of largemouth bass in both the LP-Ly and LL-Ly groups were not significantly different compared to those in the Control group (P > 0.05). The condition factor and CP content of whole fish were significantly higher in the LP-Ly group than those in the Control group (P < 0.05). Compared with the Control group, the serum total cholesterol level and alanine aminotransferase enzyme activity were significantly lower in both the LP-Ly group and the LL-Ly group (P < 0.05). The protease and lipase activities in the liver and intestine of both group LL-Ly and group LP-Ly were significantly higher than those of the Control group (P < 0.05). Compared to both the LL-Ly group and the LP-Ly group, significantly lower liver enzyme activities and gene expression of fatty acid synthase, hormone-sensitive lipase, and carnitine palmitoyltransferase 1 were found in the Control group (P < 0.05). The addition of lysophospholipids increased the abundance of beneficial bacteria (Cetobacterium and Acinetobacter) and decreased the abundance of harmful bacteria (Mycoplasma) in the intestinal flora. In conclusion, the supplementation of lysophospholipids in low-protein or low-lipid diets had no negative effect on the growth performance of largemouth bass, but increased the activity of intestinal digestive enzymes, enhanced the hepatic lipid metabolism, promoted the protein deposition, and regulated the structure and diversity of the intestinal flora. [ABSTRACT FROM AUTHOR]

The Gucheng area, located in the east of the Tarim Basin, is one of the important gas exploration targets, and the Upper Cambrian dolostone is the main pay layer. The dolostone is considered to be altered by hydrothermal fluids, but the hydrothermal altering degrees are still unclear. In this study we report the petrography and in situ trace elemental data, and try to discuss the hydrothermal fluids and their impact on the Upper Cambrian dolostones. Based on the petrography and CL properties, five types of dolomites are identified. MD1 and MD2 are the matrix dolomites. The crystal size of MD1 range from approximately 30 to 100 μm, while the MD2 is larger than 200 μm. Cement dolomite (CD) occurring only in vugs and fractures is subdivided into three types depending on the CL properties. CD‐zone1 is the core of CD with dull CL colours. CD‐zone2 comprises a bright red CL colour zone and a dull CL colour zone, and CD‐zone3 is the rim of CD dolomite with bright red CL colours. MD2 and CD‐zone1 show light rare earth elements (LREE) depletion, middle rare earth elements (MREE) enrichment and negative Eu anomalies. The REEY patterns of CD‐zone3 dolomite are marked by LREE enrichment and positive Eu anomalies. CD‐zone2 is the transitional mineral phase that shows slightly LREE depletion and negative Eu anomalies. The REEY patterns of CD‐zone1 suggest that CD‐zone1 is likely formed by local redistribution of older dolomites in a closed system. The REEY patterns of CD‐zone3 may indicate a magmatic associated hydrothermal fluid. Based on the petrography and in situ trace elemental data, the Permian magmatic fluid, which is recorded in CD‐zone2 and CD‐zone3 dolomites, may be only limited within fractures, while unlikely significantly altered the matrix dolomite in the Upper Cambrian. [ABSTRACT FROM AUTHOR]

The exploration of deeply buried hydrocarbon is still a challenge for the petroleum geology. The Shunbei area is a newly discovered oil fields, located in the center of the Tarim Basin. The oil is mainly yielded from the Middle–Lower Ordovician carbonate reservoirs with depth > 7000 m in the Shunbei No. 1 and No. 5 fault zones. Calcite cements filled in vugs (v-calcite) and fractures (f-calcite) are identified in limestones and dolostones of the carbonate reservoirs. F-calcites in the Shunbei No. 1 fault zone trap secondary inclusions in trails, which comprise liquid-dominated biphase aqueous inclusions, liquid-dominated biphase oil inclusions, and/or oil-bearing triphase inclusions. F-calcite and v-calcite in the No. 5 fault zone trap secondary inclusions in trails, which consist of liquid-only monophase aqueous inclusions, liquid-dominated biphase aqueous inclusions, liquid-dominated biphase oil inclusions, liquid-only monophase oil inclusions, and/or oil-bearing triphase inclusions. The ranges of the homogenization temperature ( T h ) and ice-melting temperature ( T m − ice ) in the Shunbei No. 1 fault zone are, respectively, 130–150°C and -2.1–-1.5°C. The coexistence of liquid-only and liquid-dominated aqueous inclusions in the Shunbei No. 5 fault zone indicates that the aqueous inclusions are trapped at low temperatures. The aqueous inclusions in the Shunbei No. 5 fault zone show a range from -0.4 to -0.2°C in T m − ice which is very close to the meteoric fluid. In the context of the burial-thermal history and the Cambrian source rock evolution, the charging process of hydrocarbon in the Shunbei No. 1 and No. 5 fault zones corresponds to the Silurian and Middle Ordovician, respectively. Results of fluid inclusions indicate a tightly coupling relationship between the hydrocarbon charging process and fault system evolution in the Shunbei area. This study reveals the application of fluid inclusion under the systemically petrographic constraints to decipher the charging history of hydrocarbon, especially for the deeply buried reservoirs. [ABSTRACT FROM AUTHOR]

The Shunnan (SN) area, located in the center of the Tarim basin, NW China, is a gas field discovered in 2013, where the gas is hosted from deeply buried Ordovician carbonate reservoirs with burial depth > 6000 m and temperature > 190 °C. The most important reservoir rocks in the SN area are silicified limestones, which are characterized by multiple generations/types of authigenic quartz (Qz1–Qz2) and coarse calcite cement (CC1–CC3), in addition to other diagenetic phases. Qz1 is a replacement quartz postdating burial stylolites in both limestone and strongly silicified limestone, and Qz2 are equant and bladed quartz cements developed in fractures or vugs in strongly silicified limestone, also postdating burial stylolite. CC1 is a coarse calcite cement found in the vugs, which postdates medium crystalline dolomite and predates saddle dolomite. CC2 (including CC2a, CC2b and CC2c) is the calcite postdating Qz1 and burial stylolites. CC2a is found in fractures in limestone or slightly silicified limestone. CC2b, CC2c and CC3 are only identified in strongly silicified limestone. CC2b fills intercrystalline pores of Qz1, and CC2c fills fractures, predating Qz2. CC3 is precipitated in remaining space left by Qz2c in fractures or vugs. Sr isotopes were analyzed in CC2a and CC2c. CC2a has 87 Sr/ 86 Sr ratios of 0.70890–0.70917. CC2c is characterized with 87 Sr/ 86 Sr ratios of 0.70949–0.70972. Fluid inclusions were studied in all the quartz and coarse calcite cements. Fluid inclusions in CC2a are characterized by T h values of 118–131 °C and salinities of 22.9–25.2 wt% NaCl + CaCl 2 . Fluid inclusions from Qz2a, Qz2b, CC2b and CC2c have T h values of 143–166 °C and salinities of 14.7–23.7 wt% NaCl + CaCl 2 . Fluid inclusions in Qz2c are characterized by T h values of 125–132 °C and salinities of 24.8–26.8 wt% NaCl + CaCl 2 , and those in CC3 by T h values of 86–101 °C and salinities of 22.9–25.2 wt% NaCl + CaCl 2 . The T h drop, from Qz2a, Qz2b and CC2c to Qz2c and CC3, cannot be explained by normal burial diagenesis, suggesting a hydrothermal event associated with the main phase of silicification. The relatively low temperature recorded by CC3 implies that the hydrothermal event possibly took place in the Devonian rather than Permian as previously thought. [ABSTRACT FROM AUTHOR]

The Shunnan area is a newly discovered hydrocarbon field in Shuntuoguole lower uplift, in which the host rocks are Lower–Middle Ordovician carbonates. The carbonate reservoirs are well affected by hydrothermal silicification with well‐preserved intercrystalline pore of replacement quartz and megaquartz cements. Based on the petrography, pore types, and diagenetic processes, this research evaluated the reservoir quality and re‐constructed the porosity evolution in different diagenetic stages. Samples are collected from 7‐cored wells distributed along NNE‐ or ENE‐trending sinistral strike‐slip faults. Nine types of lithofacies were identified in the study area, including mudstone, bioclast wackestone, peloidal bioclast packstone, boundstone, peloidal grainstone, ooid grainstone, slightly silicified limestone (silica less than 25%), strongly silicified limestone (silica around 50%), and chert. Chert has better porosity (average 21.3%) and permeability (average 44.7 mD) than other lithofacies. The main reservoir pores are mainly developed in forms of fractures, intercrystalline replacement quartz and dissolved vugs. The porosity evolution shows that the primary porosity was limited due to cementation and compaction, and the earlier secondary porosity was occlusive as a result of coarse calcite cementation. Therefore, the precursor limestones may be tight, and the reservoir quality of the Lower–Middle Ordovician carbonates was controlled by hydrothermal silicification. During the hydrothermal silicification event, the burial depth of the Lower–Middle Ordovician carbonates was more than 3,000 m and their stratum temperature was higher than 120°C, representing a deep burial condition. The statistical data of porosity‐depth/temperature trends for carbonates suggest that the early secondary pores would be significantly reduced when the burial temperature reaches 100°C (or depth of strata reaches 3,000 m). Therefore, the dissolved vugs in strongly silicified limestone or hydrothermal chert are caused by hydrothermal silicification and not inherited from precursor carbonate rocks. [ABSTRACT FROM AUTHOR]

In this paper, the authors have summarized and analyzed the petrology and isotope and trace element characteristics of host rocks and calcite cements in the Yingshan and Yijianfang formations of Lower-Middle Ordovician in the Shunbei area of the Tarim Basin. The result successfully reveals four types of limestones and four types of calcite cements, such as the sparry grainstone (SG), the microcrystalline grainstone (MG), the micrite (MC), the silicified limestone (SL), the calcite coexisting with silicon in SL (C1), the calcite which develops in fractures or between the broken siliceous breccias (C2), the calcite which fills between the broken particles (C3), and the calcite filling the fractures of all the host rocks and cements (C4). The high U/Th and Sr/Ba ratios of all the calcite cements indicate that the fluids that formed them were of comparatively higher salinity in burial environments, and the differentiation of their Sr-isotopes, Fe, and Mn contents clearly shows two types of diagenetic fluids: the fluid forming C2 and C3 is the inherited seawater closely related to the host rocks, and the fluid forming C1 and C4 is the silica-rich hydrothermal fluid from the lower strata and flowed through the possible clastic strata. [ABSTRACT FROM AUTHOR]

The Lower Triassic Jialingjiang Formation, characterised by a carbonate–evaporite succession, is one of the important pay layers in the eastern Sichuan Basin. Several diagenetic events were identified in this study, including meteoric dissolution, dolomitisation, anhydrite/gypsum replacement/cementation, TSR, BSR, and multiple calcite cementation (C1–C3). Dolomitisation and anhydrite/gypsum replacement/cementation are the major diagenetic events affecting reservoir porosity. The dolostone is composed of D1, D2, and D3 dolomite. D1 dolomite is very finely crystalline, dominating in the low-energy, restricted depositional facies. D2 dolomite is finely crystalline, constituting a major portion of the dolostones. D3 dolomite is depositional fabric retentive dolomite, including dolo-wacke-/packstone, dolo-grainstone, and dolo-boundstone. Four types of anhydrites (A1–A4) were identified in the core and thin sections. A1 is stratabound anhydrite. A2 is the anhydrite in dolostones, filling in the interparticle spaces in dolo-grainstone and the intraparticle spaces in dolo-wackestone. A3 is the anhydrite in limestones, which occurs non-fabric-selectively. A4 is the anhydrite filling in the fractures. The diagenetic anhydrites (A2–A4) are interpreted to postdate to major dolomitisation. D1 and D2 dolomites are characterised by δ13C VPDB values of −3.4–+7.3 ‰ and δ18O VPDB values of −4.7−-2.4 ‰. The REE patterns of D1–D3 dolomites are characterised by light rare earth element (LREE) depletion relative to heavy rare earth elements (HREE) ((Pr/Tm) N of 0.54–1.16, 0.81 ± 0.20), middle rare earth elements (MREE) enrichment (BSI values of 1.06–1.38, 1.26 ± 0.10), and negative Ce anomalies (Ce/Ce* ratios of 0.74–0.94, 0.83 ± 0.07). The diagenetic anhydrites (A2–A4) show δ34S V-CDT values of +25.9–+45.7 ‰, similar to those of the stratabound anhydrite (+29.6–+43.0 ‰). The large variations in the δ13C VPDB values of D1 and D2 dolomites are attributed to methanogenesis and BSR. The δ18O VPDB values and REE characteristics of D1–D3 dolomites suggest that the carbonates are dolomitised by the mesohaline fluid. The δ34S V-CDT values of A1–A4 indicate that the diagenetic anhydrites are formed by redistribution in a closed system. The petrographical and geochemical data suggest that the Jialingjiang carbonate evolved in a closed system during burial diagenesis. Primary pores dominate in the Jialingjiang carbonate reservoirs, and the boundstone and grainstone show the best porosities based on the porosityversus lithofacies data. Therefore, we propose that the lithofacies, instead of the diagenetic events, are the key factors of the Jialingjiang carbonate. The resisting compaction of dolomitisation helps preserve the reservoir porosity, and anhydrite is the major diagenetic event destroying the reservoir porosity. • Lithofacies are the key factor of the reservoir qualities. • Petrography and geochemical work suggest the closed diagenetic systems. • Jialingjiang carbonate is dolomitized by mesohaline fluids predating diagenetic anhydrite. • Anhydrite selectively replace calcitic part in Jialingjiang carbonate. [ABSTRACT FROM AUTHOR]

Various degrees of dolomitization are widely present in the Yingshan Formation in the Gucheng area of the Tarim Basin. To determine the petrological characteristics and origin of the massive dolomites present, a rich combination of tools was well used, including previous research results, core and thin-section samples, cathodoluminescence, carbon (C-) and oxygen (O-) isotopes, strontium (Sr-) isotopes and content, and burial-thermal history data. The results of this analysis successfully reveal three primary matrix dolomites and three special cements, as follows: (1) microcrystalline to very fine crystalline nonplanar-a dolomite (MD1); (2) very fine to fine crystalline planar-s to planar-e dolomite (MD2); (3) medium to coarse crystalline nonplanar-a to planar-s dolomite (MD3); (4) coarse crystalline nonplanar-a saddle dolomite cement (SD) and (5) medium to coarse crystalline calcite cements (C1 and C2). Among them, MD1 precipitated from the reflux of mildly evaporated seawater, and MD2 was formed by the first significant recrystallization of MD1 in shallow burial environments. In particular, some MD3 was formed by the second significant recrystallization of MD1 in medium-burial environments. The others, even SD, were likely the products of the third significant recrystallization and cementation in deep-burial environments that precipitate under the action of a hydrothermal fluid mixture composed of mantle-derived fluid and Cambrian thermal brine. In addition, C1 and C2 would form close to the times in which the Himalayan and Late Caledonian–Early Hercynian hydrocarbon charging events occurred, respectively. • The origin of the dolomites of the Yingshan Formation in the study area was analysed systematically for the first time. • MD had undergone dolomitization and varying degrees of recrystallization by two different sources of fluids. • C1 and C2 formed during the Himalayan and Late Caledonian–Early Hercynian orogenic periods respectively. [ABSTRACT FROM AUTHOR]