Method for determining hydrothermal activity age of volcanic reservoir

Abstract

The invention discloses a volcanic rock reservoir hydrothermal activity age determination method, and relates to the technical field of volcanic rock identification. Comprising the following steps: acquiring a zircon sample target of a volcanic reservoir to be detected; carrying out laser Raman spectrum test to obtain zircon sample target Raman spectrum data; processing the data to obtain the peak position and the full width at half maximum of the vibration peak v3SiO4 of the zircon sample target; fitting the full width at half maximum of the vibration peak v3SiO4 and the position parameters of the center of the wave crest so as to determine the morphological characteristics and components of the inclusions in the zircon; performing isotope proportion and trace element composition analysis to determine the formation age of zircon; and constructing a full width at half maximum-time fitting curve, and judging the formation period of the hydrothermal mineral symbiotic with the zircon. The method not only can be used for dividing the zircon period in volcanic lava, but also can be used for better judging the formation cause of the zircon, and provides an important judgment basis for the volcanic reservoir suffered from the later hydrothermal / tectonic action event and the time of the later hydrothermal / tectonic action event.

Description

Technical Field

[0001] The present invention relates to the technical field of volcanic rock identification, and particularly relates to a method for determining the age of hydrothermal activity in volcanic rock reservoirs. Background Art

[0002] Zircon is the most important accessory mineral in magmatic rocks, sedimentary rocks, metamorphic rocks and lunar rocks, and has the characteristics of stable physical and chemical properties, low common lead content, high closure temperature, etc. Zircon U-Pb dating is the most commonly used method in isotope geochronology research and is an important means to limit problems such as hydrocarbon reservoir formation and later fluid transformation. The main zircon U-Pb dating methods include single-grain microthermal ionization mass spectrometry (TIMS), single-grain volcanic lava zircon evaporation method, ion probe mass spectrometry (SHRIMP), laser inductively coupled plasma mass spectrometry (LA-ICP-MS), and (U-Th) / He fission track dating method, etc. However, no matter which zircon U-Pb dating method is selected, the ultimate goal is to give a convincing and reasonable geological interpretation of the obtained U-Pb isotope age.

[0003] However, volcanic lava reservoirs are easily modified by later complex tectonic fluid actions, resulting in complex zircon genesis in volcanic lava. In addition to the main minerals such as albite, quartz, and calcite in the diagenetic minerals of volcanic lava reservoirs, hydrothermal accessory minerals such as titanite, zircon, apatite, and monazite are also found. Fluid inclusions are abundant in each diagenetic mineral, and a large number of various types of hydrocarbon inclusions (gaseous hydrocarbons, liquid hydrocarbons, methane, asphalt, etc.) are seen; at the same time, a large number of symbiotic mineral inclusions can be seen in hydrothermal minerals. Therefore, the use of zircon inclusions can limit the hydrothermal activity period, thereby accurately limiting the time of later transformation of volcanic lava reservoirs.

[0004] The publication number is CN112748139A, and the patent name is "A method for discriminating the genetic type of zircon by using zircon structure", which specifically includes: collecting rock and ore samples; selecting non-magnetic heavy mineral zircon and preparing an analysis sample target; collecting backscattered electron images and cathodoluminescence electron images of zircon samples; comparing the collected backscattered electron images and cathodoluminescence electron images of zircon with typical zircon for crystal morphology and internal structure feature comparison, so as to discriminate the genetic type of zircon. Another publication number is CN112748175A, and the patent name is "A method for discriminating the genesis of zircon by using the trace element composition of zircon", which specifically includes: preparing a zircon sample target; performing in-situ trace element composition analysis on zircon; using the chondrite-normalized rare earth element distribution curve combined with trace element characteristics to discriminate the genesis of zircon.

[0005] The defects of the above-mentioned existing technologies are: they all analyze the components of magmatic zircon and hydrothermal zircon to qualitatively analyze the genesis of zircon, and cannot judge the activity age of the hydrothermal fluid in the later volcanic rock reservoir. Summary of the Invention

[0006] Based on this, in view of the above technical problems, it is necessary to provide a method for determining the age of hydrothermal activity in volcanic rock reservoirs.

[0007] An embodiment of the present invention provides a method for determining the age of hydrothermal activity in volcanic rock reservoirs, including:

[0008] Obtaining a zircon sample target of the volcanic rock reservoir to be measured;

[0009] Performing laser Raman spectroscopy testing at a fixed position of the zircon sample target through a confocal Raman spectrometer to obtain Raman spectroscopy data of the zircon sample target; processing the Raman spectroscopy data of the zircon sample target through LabSpec software to obtain the peak position and full width at half maximum of the vibration peak ν3SiO4 of the zircon sample target; using the Lorentz or Gaussian algorithm to fit the position parameters of the full width at half maximum and the peak center of the vibration peak ν3SiO4 to determine the morphological characteristics and composition of the inclusions in the zircon;

[0010] Performing isotope ratio and trace element composition analysis at the same position of the zircon sample target through a laser ablation system and an inductively coupled plasma mass spectrometer to obtain the time corresponding to the vibration peak ν3SiO4 of the zircon sample target to determine the formation age of the zircon;

[0011] According to the age of the zircon, the composition and morphological characteristics of the inclusions in the zircon, constructing a full width at half maximum-time fitting curve to judge the formation period of the hydrothermal minerals symbiotic with the zircon.

[0012] Optionally, obtaining the zircon of the volcanic rock reservoir to be measured includes: after sticking the zircon sample on a target suitable for laser plasma mass spectrometry with double-sided tape, fixing it with colorless and transparent epoxy resin, and polishing the surface after curing to form a zircon sample target.

[0013] Optionally, the parameters of the confocal Raman spectrometer are set as laser wavelength 532nm, grating 1800l / mm, exposure time 10S, laser energy 10%, and accumulation times 2.

[0014] Optionally, when using the Lorentz or Gaussian algorithm to fit the position parameters of the full width at half maximum and the peak center of the vibration peak ν3SiO4, correcting the full width at half maximum of the zircon, and the calculation formula is:

[0015]

[0016] where b is the true full width at half maximum, bs is the measured full width at half maximum, and s is the Raman light resolution.

[0017] Optionally, the peak position and full width at half maximum values of the vibration peak ν3SiO4 include:

[0018] The peak position of the asymmetric stretching Raman peak ν3 is 1007cm -1Left and right, and the half-height width ≤ 5 cm -1 , and it is completely crystalline;

[0019] The peak position of the asymmetric stretching Raman peak ν3 is between 1000 and 980 cm -1 and the half-height width is 10 - 30 cm -1 , and it is metamict zircon;

[0020] The peak position of the asymmetric stretching Raman peak ν3 < 980 cm -1 and the half-height width > 30 cm -1 , and it is strongly metamict zircon.

[0021] Optionally, the time corresponding to the vibration peak ν3SiO4 of the obtained zircon sample target includes:

[0022] Judge whether the zircon age is less than 500 Ma, and judge the correlation between the half-height width of the zircon and the U-Pb dating result;

[0023] If the correlation > the correlation threshold, it is considered that the zircon correlation is strong, and the formation age of the zircon is determined by using the U-Pb dating result and the half-height width fitting regression equation of the zircon.

[0024] Optionally, using the U-Pb dating result and the half-height width fitting regression equation of the zircon to determine the formation age of the zircon includes:

[0025] t = 19.642e 0.313x

[0026] where x is the corrected half-height width and t is the fitting time of this sample.

[0027] The above method for determining the hydrothermal activity age of a volcanic rock reservoir provided by the embodiments of the present invention has the following beneficial effects compared with the prior art:

[0028] By coordinating the results of laser Raman spectroscopy measurement and analysis, isotope ratio and trace element composition analysis, the present invention can not only be used to divide the zircon stages in volcanic lava, but also has a good determination of the zircon origin, providing an important identification basis for the later hydrothermal / tectonic action events and time of the volcanic rock reservoir.

[0029] In addition, the present invention uses the Lorentz or Gaussian algorithm to fit the half-height width and the position parameters of the peak center of the vibration peak ν3SiO4, can determine the composition of the inclusions in the zircon, thereby inferring the formation period of this type of zircon, and combining the thin section observation and the isotope ratio result can judge the formation period of a certain stage of minerals. Description of the Drawings

[0030] Figure 1 It is a schematic flow chart of a method for determining the hydrothermal activity age of a volcanic rock reservoir provided in an embodiment;

[0031] Figure 2 Schematic diagram of the peak range of zircon Raman test for a method for determining the hydrothermal activity age of volcanic rock reservoirs provided in an embodiment;

[0032] Figure 3 Raman characteristic peak map of zircon inclusions for a method for determining the hydrothermal activity age of volcanic rock reservoirs provided in an embodiment;

[0033] Figure 4 Comparison diagram of ν3 peaks of zircons with different origins for a method for determining the hydrothermal activity age of volcanic rock reservoirs provided in an embodiment;

[0034] Figure 5 FWHM-time fitting curve graph for a method for determining the hydrothermal activity age of volcanic rock reservoirs provided in an embodiment;

[0035] Figure 6 Schematic diagram of the formation period of zircon mineral inclusions for a method for determining the hydrothermal activity age of volcanic rock reservoirs provided in an embodiment. Detailed implementation manners

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] Uranium U and thorium Th in zircon will continuously decay, accumulate in zircon and form Pb element; there is almost no common lead in zircon, so the source of lead in zircon can be considered to come from the radioactive decay of U and Th elements, and the daughter nuclei and α particles generated by radioactive decay will damage the crystalline structure of zircon and thus cause lattice damage. These lattice damages will gradually accumulate in the zircon crystal until it causes the complete metamorphism of zircon. Therefore, the lattice damage of zircon and the Pb element content can be considered as a function of time, and the total amount of zircon lattice damage can be obtained by a laser Raman instrument. There is a certain content of inclusions in some zircons, and some of the inclusion particles are small, which are difficult to judge by CL or a light transmission microscope. Laser Raman can be used for in-situ testing to analyze whether there are mineral inclusions at the pre-drilled points. Therefore, before LA-ICP-MS testing, laser Raman technology can be used to preliminarily judge and screen zircons in order to obtain better zircon dating data.

[0038] Radiation damage will affect the vibration characteristics of zircon molecules in volcanic lava. As the radiation damage increases, the Raman peak position shifts to a lower wave number, and the full width at half maximum (FWHM) of the Raman peak becomes wider. Laser Raman can measure the radiation damage of volcanic lava zircon. The spontaneous decay of radioactive nuclides releases alpha particles and the body of the radiated alpha particles, which will damage the nearby lattice, which is called the radiation damage Dα of volcanic lava zircon. When the zircon metacrystallization is high, the lattice is destroyed, and the zircon is easily transformed by hydrothermal fluids, which will cause the loss of Pb in the zircon, thus affecting the dating results. However, within a certain time range, the Raman half-width of zircon and the zircon crystallization time t are in a linear relationship. Therefore, the age of untested zircon can be inferred based on the existing zircon dating results combined with the Raman analysis results. Raman technology can determine the internal inclusions of zircon without damaging the zircon. Some zircons have many inclusions inside, and such zircons are usually not recommended for dating. Using the above method, the formation period of this type of zircon can be inferred, and the formation period of the zircon inclusion minerals can be determined. Combined with thin section observation and U-Pb dating results, the formation period of a certain period of minerals can be determined.

[0039] In one embodiment, a method for determining the age of hydrothermal activity in a volcanic reservoir is provided, such as Figure 1 As shown, the method includes:

[0040] Step 1: Sorting zircons in volcanic lava, randomly selecting at least 25 zircons to make zircon sample targets.

[0041] Step 2: Perform laser Raman spectroscopy test at a fixed point of the zircon sample target using a microscopic confocal Raman spectrometer to obtain Raman spectral data of the zircon sample target; process the Raman spectral data of the zircon sample target using LabSpec software to obtain the peak position and half-width of the vibration peak ν3SiO4 of the zircon sample target; use the Lorentz or Gaussian algorithm to fit the half-width of the vibration peak ν3SiO4 and the position parameters of the peak center to determine the morphological characteristics and composition of the inclusions in the zircon.

[0042] Step 3: Use a laser ablation system and an inductively coupled plasma mass spectrometer to analyze the isotope ratio and trace element composition at the same point on the zircon sample target, and obtain the time corresponding to the vibration peak ν3SiO4 of the zircon sample target to determine the formation age of the zircon.

[0043] Step 4: Determine the formation period of the hydrothermal minerals coexisting with zircons based on the age of zircons, the composition of inclusions in zircons, and their morphological characteristics.

[0044] In the step 1, the zircon samples (number ≥ 25) are adhered to a target suitable for laser plasma mass spectrometry with double-sided tape, and then fixed with colorless transparent epoxy resin. After curing, the surface is polished to form a zircon sample target.

[0045] In step 2, a Renishaw inVia-Qontor confocal Raman spectrometer was used to measure the composition. The laser wavelength was 532 nm, the grating was 1800 l / mm, the exposure time was 10 s, the laser energy was 10%, and the number of accumulations was 2. Before the laser Raman spectroscopy test of zircon, single-crystalline silicon was used for calibration (the Raman peak of single-crystalline silicon is 520.7 cm -1 ), and the offset of the Raman spectral characteristic peak was less than 0.01 cm -1 . The Raman characteristic peak of zircon collected in the experiment was the peak position and full width at half maximum of the asymmetric stretching Raman peak ν3.

[0046] Among them, the peak position of the asymmetric stretching Raman peak ν3 was about 1007 cm -1 and the full width at half maximum ≤ 5 cm -1 , which was completely crystalline; the peak position of the asymmetric stretching Raman peak ν3 was between 1000 - 980 cm -1 and the full width at half maximum was 10 - 30 cm -1 , which was metamictized zircon; when the peak position of the asymmetric stretching Raman peak ν3 < 980 cm -1 and the full width at half maximum > 30 cm -1 , it was strongly metamictized zircon. Strongly metamictized zircon was excluded using the ν3 peak and full width at half maximum of zircon. At the same time, by comparing the Raman characteristics and inclusion characteristics of the same zircon, the inclusion composition could be qualitatively judged using the inclusion characteristic peak.

[0047] In step 2, LabSpec software was used to process the Raman spectral data of the zircon sample target, and the peak position and full width at half maximum of the vibration peak ν3SiO4 were obtained. The Lorentz or Gaussian algorithm was used to fit the position parameters of the full width at half maximum and the peak center of the vibration peak ν3SiO4. And the full width at half maximum of zircon was corrected using equation (1):

[0048]

[0049] where b is the true full width at half maximum; bs is the measured full width at half maximum; s is the Raman light resolution.

[0050] Highly metamictized zircon was excluded using the full width at half maximum of the zircon sample target. Because the metamictized zircon was in a highly disordered state, Pb was extremely easy to diffuse, resulting in Pb loss, thus affecting the accuracy of U-Pb system dating; at the same time, zircons with fewer inclusions were selected for dating, as the elements in the inclusions themselves would affect the accuracy of zircon dating results and trace element contents.

[0051] In step 3, an Analyte Excite 193nm gaseous excimer laser ablation system or a GeolasPro laser ablation system is used in combination with an inductively coupled plasma mass spectrometer to analyze the in-situ isotope ratios and elemental compositions of U, Th, and Pb in the selected zircons.

[0052] In step 3 described above, zircon 207 Pb / 206 Pb, 207 Pb / 235 U, 206 Pb / 238 U and 208 Pb / 232 Th isotope ratios and 1sigma are used to calculate the U-Pb crystallization age of zircons.

[0053] In step 4 described above, after excluding the captured zircons, it is judged whether the zircon age is less than 500 Ma, and the correlation between the full width at half maximum of zircons and the U-Pb dating results is judged; if the correlation > the correlation threshold (0.7), it can be considered that the correlation of zircons in this sample is strong, and the U-Pb dating results of zircons and the full width at half maximum fitting regression equation can be used; the remaining zircons with more inclusions, belonging to semi-crystalline - crystalline but not U-Pb dated, are brought into this equation (2) to speculate the formation age of zircons.

[0054] In step 4 described above, the formation period of late hydrothermal minerals in the sample can be judged by using the composition and morphological characteristics of inclusions in zircons and the zircon age.

[0055] Exemplarily, step one, prepare a zircon sample target; petrological observations can be carried out on the corresponding sample thin sections. This sample is volcanic lava, which has been modified by late hydrothermal fluids. Quartz and calcite can be seen in the sample. The thin section identification results show that quartz precipitated earlier than calcite. There are accessory minerals such as titanite and apatite in the sample.

[0056] Fix the zircon samples (quantity ≥ 25) on a target suitable for laser plasma mass spectrometry with double-sided tape, and fix them with colorless transparent epoxy resin. After curing, polish the surface to the center of the zircons.

[0057] Step two, Raman characteristic analysis of zircons and inclusions;

[0058] Use a Renishaw inVia-Qontor confocal micro-Raman spectrometer to measure the composition of the sample target prepared in step one. The laser wavelength is 532 nm, the grating is 1800 l / mm, the exposure time is 10S, the laser energy is 10%, and the accumulation times are 2. Before performing laser Raman spectroscopy tests on zircons, single-crystalline silicon is used for calibration (the Raman peak of single-crystalline silicon is 520.7 cm -1), the Raman spectral characteristic peak shift is less than 0.01 cm -1 , and test the Raman spectrum of zircon inclusions. The spectral characteristics of zircon are as follows Figure 2 . A total of four types of mineral inclusions were identified in this sample, namely calcite, quartz, apatite, and asphalt. The spectral characteristics of these zircon inclusions are shown in Appendix Figure 3 .

[0059] Step 3: Analyze the in-situ trace element composition of zircon.

[0060] Use the Analyte Excite 193nm gaseous excimer laser ablation system or GeolasPro laser ablation system at the same point of the zircon tested by Raman in Step 2, and cooperate with an inductively coupled plasma mass spectrometer to analyze the isotope ratios and trace element compositions of U, Th, and Pb in zircon in-situ.

[0061] The zircon dating results, Raman spectra of zircon inclusions, and zircon Raman results are shown in Table 1.

[0062] Table 1 Zircon dating results, Raman spectra of zircon inclusions, and zircon Raman results

[0063]

[0064] In Step 3, captured zircon, magmatic zircon, and hydrothermal zircon exist in this sample. CL images show that these three types of zircon have similar aspect ratios, similar CL image colors, and oscillatory zoning. Using Raman analysis, it can be seen that there are significant differences in the full width at half maximum (FWHM) of these three types of zircon. Because the formation periods of these three types of zircon are different and the cumulative radiation damage amounts are different, the FWHM can be used to make judgments.

[0065] Step 4: After removing the captured zircon, judge whether the zircon age is less than 1500 Ma, and judge the correlation between the zircon FWHM and the U-Pb dating results; if the correlation > 0.7, it can be considered that the correlation of zircon in this sample is strong, and the zircon U-Pb dating results and the FWHM regression equation can be used; bring the remaining zircons with more inclusions, belonging to semi-crystalline - crystalline but not U-Pb dated, into this equation to estimate the formation age of zircon. The formation period of the late hydrothermal minerals in the sample can be judged using the composition and morphological characteristics of the inclusions in zircon and the zircon age.

[0066] For the age-FWHM fitted in this experiment, a regression equation is made to obtain the age fitting curve for this sample; for some zircons with more inclusions that have not been U-Pb dated and have a lower degree of devitrification, their formation ages can be estimated.

[0067] For this sample, the formation age of volcanic lava is in the range of 258 - 261 Ma, and the formation times of two hydrothermal periods are 159.6 ± 1.6 Ma and 24 - 77 Ma respectively. Correlation statistics were conducted on the full width at half maximum (FWHM), peak position, dating results, and trace elements in zircon of the sample. It can be seen that the relationship between the FWHM and age is relatively large, while the relationship between trace elements, the peak position of the vibration peak ν3SiO4, etc. and zircon is relatively small. Therefore, in this experiment, the fitting regression equation of zircon dating results - FWHM can be used, and the following results are obtained:

[0068] t = 19.642e 0.313x (R 2 = 0.74) ------- (Equation 2)

[0069] where x is the corrected FWHM and t is the fitting time of this sample. The results are shown in Table 2 and Figure 5 as follows.

[0070] Table 2

[0071]

[0072]

[0073] The formation time of mineral inclusions is as Figure 6 shown; Apatite is a common mineral inclusion in zircon. This type of mineral is widely distributed in magmatic zircon, captured zircon, and hydrothermal zircon, and cannot be used as a characteristic mineral for determining the origin in zircon; while quartz mainly exists in zircon formed between 25 - 175 Ma, calcite exists in zircon formed between 65 - 81 Ma, and bitumen is distributed in zircon formed between 80 - 161 Ma. It can be considered that the formation period of quartz is earlier, and the amount of quartz formed by hydrothermal is relatively large. Therefore, more quartz can be captured in zircon inclusions. According to the U - Pb dating results, it can be considered that quartz was formed in the hydrothermal of 159.6 ± 1.6 Ma; the formation period of calcite is later than that of quartz, mainly formed in the second - stage hydrothermal of 24 - 77 Ma, and bitumen is formed between the two - stage hydrothermal minerals. Therefore, the formation sequence of minerals in a certain area is quartz - bitumen - calcite, and this result also conforms to the thin - section observation results.

[0074] Since the trace - element composition of zircon in different geological bodies varies due to their formation geological environment. The discrimination of this type of zircon inclusion is for the same geological body (the same analysis sample), and zircon inclusions in different regions are different. There are differences in the Raman characteristics of zircon with different lithologies, and the fitting - curve results should be modified accordingly.

[0075] In summary, the present invention has the following advantages:

[0076] 1. The laser Raman technique obtains results faster and at lower cost compared to (U - Th) / He dating.

[0077] 2. Laser Raman testing of volcanic lava zircons does not damage the structure and composition of volcanic lava zircons. After the test, the volcanic lava zircons can be used for other experimental analyses; while in (U-Th) / He dating, the volcanic lava zircons need to be etched, which will completely destroy the volcanic lava zircons and they cannot be used for other experiments afterwards.

[0078] 3. Combining the results of laser Raman spectroscopy measurement analysis, isotope ratio and trace element composition analysis can not only be used to divide the zircon stages in volcanic lava, but also have a good determination of zircon genesis, providing important identification basis for the later hydrothermal / tectonic events and time suffered by volcanic rock reservoirs.

[0079] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A method for determining the age of hydrothermal activity in a volcanic reservoir, characterized in that: include: Obtain zircon sample targets from the volcanic rock reservoir to be tested; Laser Raman spectroscopy is performed at a fixed point of a zircon sample target using a microscopic confocal Raman spectrometer to obtain Raman spectral data of the zircon sample target; the Raman spectral data of the zircon sample target is processed using LabSpec software to obtain the peak position and half-width of the vibration peak ν3SiO4 of the zircon sample target; the half-width and peak center position parameters of the vibration peak ν3SiO4 are fitted using a Lorentz or Gaussian algorithm to determine the morphological characteristics and composition of inclusions in zircon; The isotope ratio and trace element composition were analyzed at the same point of the zircon target by laser ablation system and inductively coupled plasma mass spectrometry to obtain the time corresponding to the vibration peak ν3SiO4 of the zircon target and determine the formation age of the zircon. According to the age of zircon, the composition of inclusions in zircon and their morphological characteristics, a half-width-time fitting curve was constructed to determine the formation period of the hydrothermal minerals coexisting with zircon.

2. The method for determining the age of hydrothermal activity in a volcanic reservoir according to claim 1, characterized in that: The method of obtaining zircon from the volcanic reservoir to be tested comprises: sticking the zircon sample on a target suitable for laser plasma mass spectrometry with double-sided adhesive, fixing it with colorless transparent epoxy resin, and polishing the surface after curing to form a zircon sample target.

3. The method for determining the age of hydrothermal activity in a volcanic reservoir according to claim 1, characterized in that: The parameters of the micro-confocal Raman spectrometer are set as follows: laser wavelength of 532 nm, grating of 1800 l / mm, exposure time of 10 s, laser energy of 10%, and accumulation times of 2.

4. A method for determining the age of hydrothermal activity in a volcanic reservoir according to claim 1, characterized in that: The half-width of zircon is corrected when the half-width of the vibration peak ν3SiO4 and the position parameters of the peak center are fitted using the Lorentz or Gauss algorithm. The calculation formula is: Among them, b is the true half-width, bs is the measured half-width, and s is the Raman light resolution.

5. The method for determining the age of hydrothermal activity in a volcanic reservoir according to claim 1, characterized in that: The peak position and half-height width of the vibration peak ν3SiO4 include: The asymmetric stretching Raman peak ν3 is at 1007 cm -1 Left and right and half-height width ≤ 5cm -1 , which is completely crystalline; The asymmetric stretching Raman peak ν3 is between 1000 and 980 cm -1 Between and half-height width 10~30cm -1 , which is metamorphic zircon; Asymmetric stretching Raman peak ν3 peak position <980cm -1 And half height width>30cm -1 , which is a strongly metamorphic zircon.

6. The method for determining the age of hydrothermal activity in a volcanic reservoir according to claim 1, characterized in that: The time corresponding to the vibration peak ν3SiO4 of the zircon sample target is obtained, including: Determine whether the zircon age is less than 500Ma, and determine the correlation between the zircon half-width and U-Pb dating results; If the correlation is greater than the correlation threshold, the zircon correlation is considered to be strong, and the zircon formation age is determined using the zircon U-Pb dating results and the half-width fitting regression equation.

7. A method for determining the age of hydrothermal activity in a volcanic reservoir as claimed in claim 6, characterized in that: The method of determining the formation age of zircon by using zircon U-Pb dating results and half-width fitting regression equation includes: t=19.642e 0.313x Where x is the correction half-width, and t is the fitting time of this sample.

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