The Wagner Basin (WB) is a shallow basin (depth < 225 m) belonging to the northernmost section of the Gulf of California rift system. Hydrothermal activity and high heat fluxes prevail in some regions of the WB. For this contribution, we report the first dataset of chemical (major and some trace elements) and isotopic compositions (δ¹⁸O, δD, ⁸⁷Sr/⁸⁶Sr, δ¹³C) from pore water sampled at the bottom of the WB, in areas affected by hydrothermal activity. The goals of the study are to determine the origin of the fluids emanating from the anomalous heat flow zones and to characterize the physical and chemical processes controlling their composition. The 18 pore water samples are classified into two groups: low temperature (LT) and high temperature (HT) samples, according to the sampling temperature (from 16.4 to 25.6 °C, and 32.5–99.6 °C, respectively). LT samples have chemical and isotopic (δ¹⁸O and δD) compositions similar to those of present-day seawater. On the opposite, HT cores are typically more enriched in Cl (26,100–37,074 mg L⁻¹) and other elements (Br, Na, K, Ca, B and Sr) than those of present-day seawater (Cl = 20,284 mg L⁻¹). HT samples are also strongly depleted in deuterium isotopes (up to −30.48‰). This characteristic could be related to the mixing between ancient evaporated seawater and Colorado river waters. Conceptually, the origin of a saline paleo-aquifer/reservoir can be related with the gradual marine flooding of shallow lagoons and depressions at the time Gulf of California was rifting (6–8 Ma) or during the Last Glacial Maximum (20–26 Ky). Additionally, it is not ruled out that some of the deuterium depletion observed in HT samples may be related to secondary processes (e.g., clays exchange, organic matter). Radiogenic ⁸⁷Sr/⁸⁶Sr signatures (0.70929–0.70997) of the HT samples likely reflect the leaching of radiogenic continental sediments from the Colorado River (filling the WB) and authigenic minerals (e.g., calcite or barite) precipitated from seawater. Solute geothermometry indicates that HT pore fluids underwent water-rock interactions at temperature of at least 220 °C. Finally high δ¹³C values (up to +10.5‰) in DIC from HT samples indicates partial equilibration of methane with DIC, or partial reduction of DIC.

瓦格纳盆地（WB）是属于加利福尼亚湾裂谷系统最北段的浅盆地（深度<225 m）。在WB的某些地区普遍存在热液活动和高热通量。对于这方面的贡献，我们报告化学（主要和一些微量元素）和同位素组成的第一数据集（δ ¹⁸ O，δD，⁸⁷ SR / ⁸⁶的Sr，δ ¹³C）在受水热活动影响的区域，从WB底部采样的孔隙水中提取。该研究的目的是确定从异常热流区流出的流体的来源，并表征控制其组成的物理和化学过程。根据采样温度（分别为16.4至25.6°C和32.5–99.6°C），将18个孔隙水样品分为两类：低温（LT）和高温（HT）样品。LT样品具有化学和同位素（δ ¹⁸ O和δD）类似于当今海水的组合物。相反，与当今的海水（Cl = 20,284 mg L）相比，HT岩心通常更富含Cl（26,100-37,074 mg L ^-1）和其他元素（Br，Na，K，Ca，B和Sr）。^-1）。HT样品中的氘同位素也极度贫化（高达-30.48‰）。该特征可能与古代蒸发海水和科罗拉多河水之间的混合有关。从概念上讲，盐碱古含水层/水库的起源可能与加利福尼亚湾裂谷之时（6-8 Ma）或最后一次冰期最大值（20-26 Ky）期间浅泻湖和洼地的逐渐海水泛滥有关。 ）。另外，不排除在HT样品中观察到的某些氘耗竭可能与次级过程（例如，粘土交换，有机物）有关。放射源⁸⁷ Sr / ⁸⁶HT样品的Sr标记（0.70929–0.70997）可能反映了科罗拉多河（充满WB）中放射性大陆沉积物的浸出和海水中沉淀的自生矿物（例如方解石或重晶石）的浸出。溶质地热测定法表明，HT孔隙流体在至少220°C的温度下经历了水-岩石相互作用。最后在高δ ¹³ C值（高达+ 10.5‰）在DIC从HT样品指示与DIC甲烷部分平衡，或DIC的部分还原。