Skip to main content

Geochemistry of halloysite-7Å formation from plagioclase in trachyandesite rocks from Limnos Island, Greece

Buy Article:

$13.61 plus tax (Refund Policy)

Abstract:

Trachyandesite rocks, occurring over an area of about 1 km2 in the southwest part of Limnos Island, Greece, are altered mainly to halloysite. The samples were collected and analysed by polarizing microscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis. The alteration of plagioclase to halloysite follows seven discrete stages that are described in detail. The geochemical evaluation of the data shows enrichment of the light REE (LREE) over heavy REE (HREE) as expressed by the (La/Yb)n ratio. The ΣLREE range from 206.44 to 272.30, while the sum of HREE varies from 11.01 to 26.26. The (La/Yb)n ratio ranges from 9.72 to 27.64. Fractionation among LREE expressed as (La/Sm)n and between middle REE (MREE) and HREE is shown as (Tb/Yb)n ratios. The most altered rocks close to the fault zone have high (Tb/Yb)n ratios and low (La/Sm)n and Eu/Eu* ratios. Although mineralogy and clay mineral textures indicate hydrothermal genesis of halloysite, the geochemical data are not conclusive due to a secondary weathering effect.

Keywords: GREECE; HALLOYSITE FORMATION; HYDROTHERMAL ALTERATION; LIMNOS ISLAND; PLAGIOCLASE ALTERATION; REE FRACTIONATION

Document Type: Research Article

DOI: http://dx.doi.org/10.1180/claymin.2014.049.1.07

Publication date: March 1, 2014

More about this publication?
minsoc/cm/2014/00000049/00000001/art00007
dcterms_title,dcterms_description,pub_keyword
6
5
20
40
5

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
UA-1313315-23
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more