Discrimination method of marine and terrestrial sedimentary environment based on selectively extracted exchangeable strontium-barium ratio in terrigenous clastic sediments

Abstract

The invention relates to a method for discriminating marine and continental depositional environments by selectively extracting exchangeable strontium-barium ratios from terrigenous clastic sediments. The method is as follows: collect an appropriate amount of loose sediment, remove visible biological debris, dry it at low temperature and crush it to a size no larger than 100 mesh, weigh an appropriate amount of the sample and add a certain concentration of ammonium acetate or sodium acetate at a suitable solid-liquid ratio as the extraction method. Stir or oscillate (ultrasonic oscillation is also acceptable) under normal temperature and pressure conditions, perform solid-liquid separation after the reaction, and use the clear liquid for instrumental analysis (ICP-OES or ICP-MS, etc.) to determine strontium and barium, and the obtained The ion-exchangeable strontium-barium ratio is greater than 1.0 for marine depositional environment, and less than 1.0 for continental depositional environment. This method not only eliminates the interference of strontium barium in silicate minerals on the discrimination of marine and continental sedimentary environments, but also eliminates the interference of strontium and barium in provenance carbonate minerals on the identification of marine and continental sedimentary environments .

Description

technical field [0001] The invention relates to a method for discriminating marine and continental depositional environments by selectively extracting exchangeable strontium-barium ratios from terrigenous clastic sediments. Background technique [0002] Both strontium and barium belong to alkaline earth metals, and have many similar geochemical behaviors during the endogenous geological process, but due to the difference in their chemical properties during the deposition process, the geochemical behaviors diverge. During the transportation and deposition of clastic sediments from the river to the sea, due to the change of the geochemical environment (Eh, ph, salinity and other ion concentrations, etc.), especially in the estuary area where the sea-land interaction occurs, the river water presents The geochemical behaviors of strontium and barium transported in the ion state have differentiated, making continental sediments rich in barium and poor in strontium, and marine sed...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the above-mentioned problems, the applicant once invented the "Selective Extraction Method of Sedimentary Strontium and Barium in Terrigenous Detrital Sediments" to conduct selective extraction of Sedimentary Strontium and Barium in terrigenous clastic sediments and discrimination of marine and terrestrial depositional environments. The effect is greatly improved compared with the traditional total method, but in the actual application process, it is found that when the patented technology is applied to sediments with high carbonate content (such as loess), the extracted strontium is high due to the isomorphism of calcium and strontium. The ratio of strontium to barium in continental sediments is greater than 1.0, which affects the correct judgment of marine and continental sedimentary environments

[0006] The occurrence forms of strontium and barium in terrigenous clastic sediments are various, not only existing in rock-forming silicate minerals such as potassium feldspar, plagioclase, and hornblende, but also adsorbed or occurring in the process of weathering and transportation In the clay minerals formed, there are also in the authigenic minerals formed in the sedimentation process, and in the carbonate minerals transported in the form of clastic minerals; these strontium barium of different sources and origins are mainly available as ions The exchange state, carbonate-bound state, iron-manganese oxide-bound state, organic reduction-bound state, and silicate-bound state are endowed in terrigenous clastic sediments; although the invented patent method minimizes the non-sedimentary origin strontium and barium in the silicate minerals, but the strontium and barium of the proven carbonate were also extracted, which affected the correct judgment of the marine and continental depositional environment of the sediment

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