FTIR spectroscopy of Ti-chondrodite, Ti-clinohumite, and olivine in deeply subducted serpentinites and implications for the deep water cycle
FTIR spectroscopy of Ti-chondrodite, Ti-clinohumite, and olivine in deeply subducted serpentinites and implications for the deep water cycle
复制标题
深俯冲蛇纹岩中钛球粒陨石、钛斜腐石和橄榄石的 FTIR 光谱及其对深水循环的影响
DOI：
10.1007/s00410-014-0992-8
复制
发表时间：
2014-07
影响因子：
3.5
通讯作者：
Chen Jing
中科院分区：
文献类型：
--
作者：
Shen Tingting;Hermann Jorg;Zhang Lifei;Padron-Navarta Jose Alberto;Chen Jing
采用非偏振透射式傅里叶变换红外光谱分析了深俯冲蛇纹岩化辉绿岩(西天山超高压带长屋子，中国)中分离出的橄榄石颗粒，并用LA-ICPMS测定了钛含量。橄榄石光谱中的主要谱带与钛斜辉石具有显著的相似性，并被解释为片层中的OH。要量化薄层中的水分含量，需要对这些波段的红外吸收进行校准。我们通过Val Malenco的一个大单晶，通过三个正交面上的偏振傅里叶变换红外光谱测量，得到了钛的新的吸收系数为0.125+/−，0.017×ppm/cm2，它的已知含水率为1.53wt%。使用这个校准因子得到的橄榄石中的水分含量在440到2600ppm之间，并与钛含量在130ppm到1400ppm之间呈正相关。为了定量测定与橄榄石共生的钛软骨矿和钛斜方辉石中的水含量，我们建立了衰减全反射傅立叶变换红外光谱分析方法。钛软骨矿和钛软骨矿在~3,562，3,525和~3,583~3,586 cm−-1处具有相似的红外吸收峰。与橄榄石一样，钛斜长石和钛软骨矿的水分和钛含量呈正相关，表明它们是共生的，这一点已被透射电子显微镜分析所证实。我们的结果证实了以前的观点，即超镁铁质岩石的钛含量与它们在俯冲带中水的输送能力之间存在很强的相关性，而不是在水合相稳定的条件下。
Separated olivine grains from a deeply subducted serpentinized wehrlite (Changawuzi in the western Tianshan ultrahigh-pressure belt, China) were analysed with unpolarized transmission FTIR and the Ti contents were determined using LA-ICP-MS. The major bands in the olivine spectra display striking similarities to Ti-clinohumite and are interpreted as OH in lamellae. The quantification of the water content in lamellae requires calibration of the IR-absorption for such bands. We have obtained a new absorption coefficient for Ti-clinohumite of 0.125+/−0.017 ppm cm2based on polarized FTIR measurements on three orthogonal sections through a large single crystal of Ti-clinohumite from Val Malenco, which has a known water content of 1.53 wt%. The resulting water content in olivine using this calibration factor ranges from 440 to 2,600 ppm and correlates positively with the Ti content that ranges from 130 to 1,400 ppm. For the quantification of the water content in Ti-chondrodite and Ti-clinohumite that are associated with olivine, we developed a new method using attenuated total reflectance FTIR spectroscopy. Ti-chondrodite and Ti-clinohumite display similar IR bands at ~3,562, 3,525 and ~3,583–3,586 cm−1. As in olivine, the water content and Ti content correlate in both Ti-clinohumite and Ti-chondrodite, indicating an intergrowth of these minerals, which has been confirmed by TEM analyses. Our results confirm previous suggestions that there is a strong correlation between the Ti content of ultramafic rocks and their capacity to transport water to the deeper mantle in subduction zones beyond conditions where hydrous phases are stable.
登录
查看更多内容
DOI：
--
发表时间：
2007
期刊：
--
影响因子：
--
作者：
D. IrrrNcrn;Gnoncr R. RossunN
通讯作者：
D. IrrrNcrn;Gnoncr R. RossunN
影响因子：
1.5
作者：
J. Liou;R. Y. Zhang
通讯作者：
J. Liou;R. Y. Zhang
影响因子：
--
作者：
A. Walker;A. Walker;J. Hermann;A. Berry;H. O’Neill
通讯作者：
A. Walker;A. Walker;J. Hermann;A. Berry;H. O’Neill
影响因子：
3.9
作者：
V. Soustelle;A. Tommasi;S. Demouchy;D. Ionov
通讯作者：
V. Soustelle;A. Tommasi;S. Demouchy;D. Ionov
影响因子：
--
作者：
Z. Li;Cin-Ty A. Lee;A. Peslier;A. Lenardic;S. Mackwell
通讯作者：
Z. Li;Cin-Ty A. Lee;A. Peslier;A. Lenardic;S. Mackwell