A study of dispersion of heavy minerals in sedimentary formations of Mesohellenic basin

Doctoral Dissertation uoadl:1309075 1017 Read counter

Unit:
Τομέας Ορυκτολογίας - Πετρολογίας
Library of the School of Science
Deposit date:
2014-04-07
Year:
2014
Author:
Μπάμπος Πέτρος
Dissertation committee:
Βλάχου-Τσιπούρα Μαρία Επίκ. Καθηγήτρια ΕΚΠΑ (επιβλέπουσα), Μαγγανάς Ανδρέας Καθηγητής ΕΚΠΑ, Σταματάκης Μιχαήλ Καθηγητής ΕΚΠΑ
Original Title:
Μελέτη της διασποράς των βαρέων ορυκτών σε ιζηματογενείς σχηματισμούς της Μεσοελληνικής αύλακος
Languages:
Greek
Translated title:
A study of dispersion of heavy minerals in sedimentary formations of Mesohellenic basin
Summary:
Mesohellenic basin (MHB) is spreading over areas of north-western Greece and
located between Pindos mountain chain from the west, to Pelagonia
microcontinent eastward. This intramontane basin, which was constructed in the
midst of Alpine Orogeny, contains five molassic Formations, from bottom to top:
Kranea (Upper Eocene), Eptahorion (Upper Oligocene), Pentalofos (Aquitanian),
Tsotylion (Aquitanian – Burdigalian) and Odria (Burdigalian - Langhian). The
aim of this effort was the discovery of the provenance of these molassic units
along with the temporal and spatial development of MHB. During the field work,
many sand and conglomerate samples were collected from all over the
investigated area. The directions of paleocurrents were measured, as well. The
next step was the processing of the samples collection. Using the technique of
sieving, the samples were separated into four fractions: 4,0mm-1,0mm,
1,0mm-0,250mm, 0,250mm-0,063mm and <0,063mm. The heavy mineral grains were
isolated from the fraction of 0,250mm-0,063mm by applying the technique of
gravity separation, sinking the grains into heavy liquid tetrabromoethane
(d=2,96). A polarized microscope has been used thereafter for identification of
heavy mineral grains after registration of their optical properties, and a
scanning electron microscope (SEM) for microprobe analyses of garnet grains.
Various geostatistical techniques were applied on the data have been taken
during the field and laboratory work (e.g. method of moments, cluster analysis,
principal component analysis, etc). The aforementioned molassic Formations and
the modern sand covers of MHB were studied with the help of three analyses:
sieving analysis, analysis of paleocurrents and analysis of heavy minerals.
Among the conclusions were the following: 1. There are indications for the
existence of a mechanism that caused vertical motion of the fragments that
surrounded the MHB. This motion reminds the passage of a wave from east to
west. 2. The pioneer sediments from Pelagonia (from east to basinward) built
the Kranea Formation. 3. The sources of clastic material turned round from east
(Pelagonia) to west (Pindos), during Upper Aquitanian times, because of the
emerging
mountain chain. 4. The clastic material of Kranea, Eptahorion and Pentalofos
derived from Pelagonia (first cycle of sedimentation), while of Tsotyli and
Odria from Pindos (second cycle). 5. The emersion of MHB took place step by
step, with a direction from south-east to north-west. 6. There is strong
evidence that ΜΗΒ behaved evolutionary like a submarine basin, having the
background of a remnant ocean basin system.
Keywords:
Mesohellenic Basin, Sieve Analysis, Paleocurrents, Heavy minerals, Garnets
Index:
No
Number of index pages:
0
Contains images:
Yes
Number of references:
291
Number of pages:
390
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