Study On Apatite Zoning Structure With The Method Of Laser Raman Spectroscopy

Accessory mineral apatite is a widely present in various types of rocks, it can remainstable over a wide range of temperature and pressure，so apatite is an important mineral in thestudy of low temperature geochronology and isotope tracer. In the growth process of theapatite, when the surrounding melt material composition, temperature and pressure conditionschange, apatite will internally generated chemical zoning. From the core of the Apatite to theedge, the content of trace elements regularly change, the structure of the zoning has recordedthe temperature and pressure conditions of the growth period. This paper attempts to applylaser Raman spectroscopy to test the ring of apatite, and analyze the differences of the Ramanspectra characteristic peak in different locations, according to the known experienced thermalhistory of the apatite, to discuss the Raman characteristic and dicipline of the differentspheres in the apatite zoning structure.It provides a basis for exploring new methods to studyapatite low temperature heat chronological.Cathodoluminescence is applied to identify the apatite zoning structure, the colour of theapatites in the CL images was mostly yellow,green,brown and purple.Apatite zoning structurewas found in the CL images of the apatite in eclogite and sandstone samples.We divided thezoning structure of the apatite into three types,each type is formed under different geneticconditions.Because the zoning structure is related to the distribution of the elements’content,we used the electron microprobe to study and explore the content of elements in theapatite profile characteristics.Elements in the section of apatite apears to be ups and downs,some elements content wave crest or trough coincided with the light and dark bands, but notuniversal.We used Laser Raman spectroscopy to test the apatites in eclogite and apatite sandstonesamples from core to rim,calculating the characteristic of the spectrum peak,shift intensityand half-height,we concluded that the spectra of Sulu eclogite samples arew more complex than that of the Songliao Basin samples.By the laser Raman experiments,we found that the peaks excursion in different zoing isnot significantly, but there is a slight variation in the intensity of the peak，it decreasedsubstantially, which may be caused by the apatite crystallization environment of hightemperature and high pressure.