Virgotrigonia peterseni
Alleman.-Petrification of a valve of a new genus of Trigonidae, a
lamellibranch mollusk of lower cretaceous (valanginian) age (135
million years). This specimen was collected and described by Vera
Allerman at Cerro La Virgen, Morro Solar, in the district of Chorrillos
in Lima. The name of the new species was given in honor of the
prominent geolist Georg Petersen in recognition of his efforts which
made possible the discovery and description of this new genius. Other
species of this genus are known in Chile and Argentina. The
fossiliferous formations at Morro Solar, Chorrillos, deserve to be
protected. Vera Alleman's collection, deposited at the Museum of
Natural History of the University Ricardo Palma. |
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Galena.- PbS, cubic system.
Location:Casapalca mine, Lima. The Casapalca mine is a producer of
lead, zinc and silver ores. It is located 130km east of Lima, at an
altitude of 4,495 m. Production of lead-zinc ores, rich in silver,
dates back to Spanish colonial time and continues to the present day.
The stratigraphic sequence consists of sedimentary and volcanic rocks
of upper cretaceous to quaternary age. This sequence was strongly
folded and intruded by various igneous bodies. The ore deposits consist
of persistent veins which cut the entire sequence. The economic
minelatization consists of galena, sphalerite, tetrahedrite and
chalcopyrite. Guido del Castillo's private collection. |
Scheelite.- CaWO4, tetragonal system.
Location: Turmalina mine, Piura. The Turmalina mine is situated in the
district of Canchaque, department of Piura.
The mineralization was deposited within a circular body of tourmaline
set in a large tonalite intrusive. The ore consists mainly of
molybdenite and chalcopyrite in the
upper part od the deposit, with pyrite, arsenopyrite, sphalerite,
wolframite and scheelite occupying the lower portion.
Mr. Guido del Castillo's private collection. |