Download Origin Albania. Petrographic name Lithic arenite Type Siliciclastic

PIETRAFORTE
Origin
Albania.
Petrographic name
Lithic arenite
Type
Siliciclastic sedimentary rock.
Macroscopic description
Fine-grain clastic rock, grey in color with more yellowish portion (altered), without
veins of calcite.
Petrographic description under the microscope
Mineralogically immature and texturally mature sandstone composed primarily of
altered quartz, lithic and feldspar granules (including microcline and plagioclase). The
granules are well classed and have a maximum diameter of a few tenths of a millimeter. The
lithic component consists of micritic calcite clasts. The trace amounts of other minerals
present include granules of muscovite, chlorite, microcrystalline quartz, zircon and opaque
minerals.
Genetic environment
The rock was formed by the accumulation of clastic sediments well classed from
granulometric standpoint (absence of matrix). This characteristic indicate a transport agent
capable of selecting the granules based on their kinetic energy, so the environment of
formation refers both to a fluvial continental environment and a deltaic or coastal marine
environment. The composition of the clasts, the quartz and feldspar granules on the one hand and
the micritic carbonate granules on the other, indicate that the sediment derived from a mixed-feed
basin where both upper-crust carbonatic rocks and medium-lower-crust igneous and
metamorphic rocks (crystalline base) outcropped.
Results of chemical analysis (% by weight):
SiO2
TiO2 Al2O3 Fe2O3 MnO MgO
CaO
Na2O
K2O
P2O5
LOI
Tot
51.53
0.299
18.01
0.97
0.66
0.06
17.27
98.80
4.55
2.34
0.222
2.90
Photos under the petrographic microscope
The following photos were taken on thin sections.
PO-1000! .jpg – Panoramic of quartz , feldspar, and calcite crystals (nicols //)
PO- 10002.jpg – Panoramic of quartz , feldspar, and calcite crystals (nicols//)
PO- 10003.jpg – K- feldspar, muscovite clasts (nicols//)
PO- 10004.jpg – Chlorite (nicols//)
PO-10005 .jpg – Microcline clasts (nicols +)
PO- 10006.jpg – Zircon and plagioclase clasts (nicols+)
PO-10007 .jpg – Microcrystalline quartz clasts (top left) and plagioclase clasts (bottom right) (nicols+)
PO-10008 .jpg – Panoramic of quartz, feldspar, calcite and muscovite clasts (nicols +)
PO- 10009.jpg – Muscovite clast (nicols +)
Flexural strength UNI EN 12372/2001
The flexural strength test was performed according to UNI EN 12372/2001
standard on ten specimens.
The following are the minimum, maximum and arithmetic mean values of
flexural strength obtained on dry specimens (Rtf ):
a
Rtf min = 14.0 MPa Rtf
max = 19.4 MPa
a
a
mean Rtfa = 17.2 MPa
Freeze/thaw resistance UNI EN 1341/2003
The results of the flexure testing described above were compared with those of a
flexure test performed on ten specimens subjected to 48 freeze/thaw cycles..
The following are the minimum, maximum and arithmetic mean of the flexural
resistance test on specimens subjected to freeze/thaw cycles (Rtf ):
g
Rtf min = 12.5 MPa Rtf
g
max
=
17.9
g
MPa
mean Rtfg = 14.8 MPa
A comparison of the mean Rtfa values with those of Rtfg shows a slight decrease in
flexural strength, so it falls into Class 1, indicating a strength variation less than or equal to
20%, and the material can be described as “resistant” according to table 6 UNI EN 1341/2003.
Skid/slip resistance UNI EN 1341/2003
The test performed according to UNI EN 1341/2003 standard Appendix D on six
specimens provided the following mean value:
USRV = 80