W1 Intro Flashcards
Petrology is
the study of rocks
Petrography
description of rocks
Earths layers
crust, mantle, outer core, inner core
Earths crust and matle are made of
silicate minerals (mostly olivine)
most abundant mineral in earth
olivine
Earths core predominantl
nickel and iron
doesnt oxidize because it has nickel
earths core is an aloi
Maximum temperature of core
about 6000Kelvin
Distance to inner core
about 6371 km
Core mantle boundary
where very hot metals meet solid silicate
Main ROck Forming Mineral Group
Main Rock Forming Mineral Group The Rock Forming Minerals Felsic Minerals Feldspar Group - plagioclase, alkali-feldspar Quartz Feldspathoid Group - nepheline, leucite Mica Group - muscovite
Mafic Minerals
Mica Group - biotite
Amphibole Group - hornblende, oxyhornblende
Pyroxene Group - clinopyroxene, orthopyroxene
Olivine
olivine rock first found on mt dunn so now known as dunite
Mineral Abbreciations
lowercase
“ite” at end
name of rock
Centrysymmetrics
crystals and grains that habve a typical shape
there are some minerals with ittegular shape and holes
Igneous Rocks form
from crystallisation of a (usually) silicate melt
Magma
molten rock within the Earth
Lava
Molten Rock on Earths urface
Textures are
Relationships of minerals within a rock
Bimodal
small and big crystals melted together
Intrusive Igneous ROcks
Cooling and solidification of magma within the Earth forms
Intrusive igneous rocks
crystallize below Earth’s surface, and the slow cooling that occurs there allows large crystals to form.
Extrusive igneaous rocks
form when magma reaches the Earth’s surface a volcano and cools quickly.
form as small crystals
Clastic Sediments
made of detrital grains (grains that have been moved)
Carbonate Sediments
made of biogenic or precipitated CaCO3
Evaporites
precipitated salts
Calcite
major rock forming mineral in carbonates
Metamorphic Rocks form
form from the transformation of igneous or sedimentary rocks by changes in temperature and pressure
i.e. from heat of an igneous intrusion or form burial deep in the crust
can see movement in frozen rock even, show evidence of deformation
stretching or compression (banding is a very telltale sign of meta rocks)
Metamorphic rocks age
have more than one age as they form at different times
Marble
metamorphosed limestone, fossils are recrystallised and porosity is lost, therefore marble is much denser and harder than limestone
Unclassified rocks
some rocks fall in the middle and can’t really be put into one box/ rock type
Other rocks may form as precipitates of hot fluids, as sublimates from gases, from concentrations of organic minerals, etc. …
Ores precipitate in fractures from hydrothermal fluids
Age of Universe
universe was formed in the BIG BANG, ~ 13.7 billion years ago
Stellar Nucleosynthesis
Elements are formed in the stars
During the evolution of a star, different processes occur producing different suites of elements…
All the heavier elements are produced in stars
Big Bang Nucleosynthesis
H and He (plus negligible C) are the only elements formed during the Big Bang
Supernovae eruptions
Elements are distributed through supernovae eruptions
