Crystals of suspended marine barite in the eastern equatorial Pacific:processes of dissolution and e

• 作 者: 孙晓霞 杨作升 范德江 李云海
• 机 构: College of Marine Geosciences,Ocean University of China,Key Laboratory of.Submarine Geosciences and
• 出 处: Chinese Journal of Oceanology and Limnology
• 发表日期: 2015年01期
• 关键词: dissolution equatorial suspended eastern arrow preservation contained dispersive

Suspended paniculate substances were sampled in the eastern equatorial Pacific in water column from surface to near bottom in five stations in 2005,from which 868 barite crystals were recovered.The barite crystals were examined under scanning electron microscopy.About 61%of the total barites crystals contained detectable Sr by energy dispersive X-ray spectrometry.Barite crystals could be classified into four groups based on their morphology:1) bladed;2) ovoid or rounded;3) arrow-like;and 4) irregularly shaped.The arrow-like barite crystals in natural environment has never been reported before.In addition,about a half of the studied crystals showed features of dissolution as cavities or holes inside of the crystals or around their edges.We found that differential dissolution of barite crystals is consequence of heterogeneous Sr distribution in barite crystals.Our results would help in understanding the biogeochemical processes of marine barite formation and preservation in seawater and marine sediments.

Suspended paniculate substances were sampled in the eastern equatorial Pacific in water column from surface to near bottom in five stations in 2005, from which 868 barite crystals were recovered. Barite crystals were examined under scanning electron microscopy. About 61% of the total barites crystals contained detectable Sr by energy dispersive X-ray spectrometry.Barite crystals could be classified into four groups based on their morphology: 1) bladed; 2) ovoid or rounded; 3) arrow-like; and 4) irregularly shaped.The arrow- like barite crystals in natural environment has never been reported before. In addition, about a half of the studied crystals showed features of dissolution as cavities or holes inside of the crystals or around their edges. We found that differential dissolution of barite crystals is consequence of heterogeneous Sr distribution in barite crystals. Our results would help in understanding the biogeochemical processes of marine barite formation and preservation in seawater and marine sediments.