Week 4-5 Flashcards
completely or partly molten rock, which on cooling solidifies to form an igneous rock composed of silicate minerals
Magma
It is the liquid component of magma composed of mobile ions of the common elements in the Earth’s crust
Melt
Gaseous components of magma
Volatiles
A process where cooling reverses the ecent of melting and ions pack more closely as temperature and rate of movement slows
Crystallization
The basic building block of silicate minerals
Silica Tetrahedron
Most abundant elements of igneous rocks
Silicon, Oxygen
Most abundant mineral group
Feldspars
Rocks between granitic and basaltic compostions are said to be
intermediate or andesitic
describe the overall appearance of rock based on size, shape, and arrangement of mineral grains
Texture
Rocks that consist of unordered ions that are frozen randomly in place are referred to as
glass
The various igneous textures result mainly from_________ whereas the minerology of an igneous rock is the consequence of _________
different cooling histories; the chemical makeup of its parent magma.
Large crystals in a porphrytic texture is called ______
Phenocrysts
The three components of magma
Liquid Component (Melt)
Solid Component
Gaseous Phase (Volatiles)
Common volatiles in magma
Water Vapor
Carbon Dioxide
Sulfur Dioxide
Common dark silicate minerals in the crust
Olivine, pyroxene, amphibple, biotite mica
Common light silicates
quartz, muscovite mica, feldspars
Factors that influence igneous texture
> cooling rate
silica content
amound of dissolved gases
Define polymerization
Union of two or more molecules of given structure to form a new compound with the same elemental proportions but with different properties and a higher molecular weight.
What are pegmatites
rocks composed of interlocking crystals all larger than a centimeter in diameter
What is pele’s hair
strands of volcanic glass from lava fountains
A pyroclastic rock can be classified a volcanic breccia if
pyroclastic fragments are greater than 2 mm
Define geothermal gradient
The increase in temperature as one goes down beneath the earth
Mineral assemblage of diorite
Sodic Plagiocalse, amphiboles, biotite
Ways for magma to generate
> increase of temp
decrease in pressure in constant heat
introduction of volatiles
Minerals under the discontinous series
olivine, pyroxene, amphibole, biotite, K-Feldspar, muscovite, quartz
Define Magmatic differentiation
Formation of one or more seconadary magmas from a single parent magma
Define magmatic assimilation
Incorporation of host rock by migrating magma
Assiilation v Magma mixing
> Assimilation involves disologing blocks of foreign host rock, melting it and then mixes with the intruding melt
Mixing of two chemically different magmas; younger buoyant magma overtakes and mix with the older existing magma.
If intrusive rocks form underground, why can geologists aquire such samples.
Observable intrusive rocks are observed at surfaces where uplifting and erosions stripped away overlying rocks
How does pegmatites form
> Form late in magma crystallization
unsually high percentage of volatiles in melt, encouraging enhanced ion migration
abnormally large crystals form
Granite has a variety of colors such as red and light gray. Why?
> reddish : k-felds dominant and dark pink
light gray: white to gray feldspars mized with small amounts of dark silicates
In a field, how would you distinguish grayish granite from diorite
> granite would have an absence of visible qtz in contrast to diorite
Explain decompression melting
> confining pressure increases rock melting temp
occurs in areas of mantle upwelling; lower pressure zones; divergent plate boundaries
removal of pressure lowers melting temp
decompression melting happeneds when confining pressure drops
How does volatiles induce melting?
> by causing rock to melt at lower temperatures; can be magnified by increased pressure
How is magma generated at subduction settings
> water is brought to the mantle via subducting lithosphere slabs
fluids migrate at the overlying mantle
addition of volatiels reduve melting temps of peridoite; generating melt
magma rises towards surface
in continental settings: ponding beneath crustal rocks; evolution from mafic to felsic magma
Explain and Illustrate Bowens Reaction Series
> an idealized sequence of mineral crystalization starting from basaltic magma under certain temperature regimes
The minerals biotite, sodic plagioclase, and amphibole belongs to the same temperature regime in the bowens rxn series. What does this imply?
> these minerals are found together in the same igneous rock particularly andesites or diorite
How is crystal settling relevant to magmatic differentiation?
> ferromagnesian minerals are dense and sinks below magma chamber
the resulting settling of minerals causes a difference in composition (mafic lower, felsic upper)
A melt produced via partial melting would be ____ compared to its parent magma. Why is that?
> richer in silica
partial melting causes felsic minerals to melt first while the mafic mineral stays in its solid form; mainly due to the difference in melting temperatures
the difference causes melt to be enriched in silica
Largest mineral group and most abundant in the crust
Silicates
Mineral with metal + oxygen combination
Oxides
The minerals iron chromiaum oxide, titanium dioxide, and hydrogen dioxide are known as
chromite , rutile, ice
minerals are are characterized with metallic luster, high density, and low hardness
a. Sulfides
These group of minerals are commonly found in evaporitic settings
Halides, Sulfates, Carbonates
The mineral the comprises the teeth and bones of living organisms
Apatite
O:Si of Cyclosilicates
[3:1]
O:Si of Nesosilicates
[4:1]
O:Si of Phyllosilicates
[2.5:1]
Most important parameters for mineral classification
> chemical composition
internal crystal structure
Classificaitons based on the Nickel-Strunz
Native Elements
Sulfides
Halides
Oxides
Nitrates
Carbonates
Borates
Sulfates
Phophates
Silicates
Organic compounds
Three types of closed rings found in cyclosilicates
> 3 tetrahedrons sharing an oxygen
6 tetrahedrons sharing an oxygen
4 tetrahedrons sharing an oxygen
Describe Inosilicates
> two oxygens atoms from each tetrahedrons bond to form open chains
Examples of tectosilicates
feldspars, quartz ,feldspathoids, zeolite group
essential mineral v accessory mineral
Essential: minerals forming the essential components of a rock
Accessory: minerals present in trivial amounds
Enumerate pyralspite
Pyrope, Almadine, Spessartine
Enumerate ugrandites
Uvarovite, grossularite, andradite
What is the Goldschmist Classification of elements
geochemical classification of elements groups the chemical elements according to their preferred host phases within the Earth
Types of chemical bonds
Ionic, Covalent, Metallic, Van der waals, Hydrogen
Minerals under K-feldspar series
Orthoclase, Microline, Sanidine
Minerals under plagioclase series
Albite, Bywotonite, Labradorite, Andesine, Oligoclase, Anorthoclase
How would you differentiate amphiboles from pyroxenes under PPL
Cleavage:
Px : 90 degrees
Amphi: 60 and 120 degrees
Can magmas be dominated by compositions other than silica (SiO2)
Yes. An example would be carbonatites which is rich in carbonate components.
How are trace elements dominant if they consitiute a small fraction of the magma compositions
They provide clues to the origin of igneous rocks.
Why is it that a magma with rich felsic composition is not expected to crystallize minerals such as olivines and pyroxenes.
> rich in silica, qtz, k-felds, sodic plag, are expected crystllizations
felsic magma depleted of Mg and FeO
How does SiO2 content relate to silicate structure and mineral strength
> more SiO2 = greater polymerization = greater mineral strength
Why does rising mantle plume pools at the moho discontinuity before rising further through the lithosphere
> rising mantle plume loses its density as when it reaches the moho
crystallization and differentiation of melt would increase its buoyancy and rise through lithosphere
Relate undercooling to the degree of crystalinity
> undercooling refers to magma cooling faster than it can crystallize
large undercooling results in high nucleation, low crystalinity
small undercooling results in lowe nucleation, high crystalinity
A thin section sample is found to be fine grained dominated by microlaths of plagioclases and volcanic glass. Phenocrysts of olivines, plagioclases, and pyroxenes generally have a feathery/skeletal texture and shows zoning. What would be its implications regarding its formation and its rock id.
> Mineral assemblage is characteristic to a mafic igneous rock
Dominance of volcanic glass and plag microliths indicate a aphanitic texure
Skeletal/feathery textures and zoning indicates rapid cooling rates
Rock may be Basalt
An outcrop far inland features pillow basalts overlain by intercalated limestones and sandstones. What would be its implication regarding its past environment.
> Sandstones usually form in terrestrial environment
Limestones form in shallow marine waters
Pillow basalts form when mafic magma extrudes and comes in contact with water
marine environment, mutiple episodes of transgression and regression
triple junction
a point at which three plates meet,
this triple juction is always stable
ridge-ridge-ridge
the approximation of the earth’s magnetic field
dipole field
difference between the Earth’s magnetic field and the best dipole field
non-dipole field
Inclination of the earth’s magnetic axis to the geographic axis
11.5 degrees
location of geomagnetic north
79 deg N, 71 deg W
the line along which the magnetic field is horizontal and has no vertical component
magnetic equator
constant stream of ionized particles emitted by the Sun
solar wind
produced where the solar wind is slowed by interaction with the Earth’s magnetic field.
bow shock
Two triple juctions that are always unstable
fault–fault–fault and fault–ridge–ridge junctions
What is space weather
active processes and interactions which take place between the magnetosphere and the solar wind
Define magnetosphere
region of space surrounding Earth where the dominant magnetic field is the magnetic field of Earth, rather than the magnetic field of interplanetary space
Define magnetosheath
region of space between the magnetopause and the bow shock of a planet’s magnetosphere
Define magnetopause
the boundary between the planet’s magnetic field and the solar wind.
What are the van allen radiation belts
zones of charged particles trappe by the Earth’s magnetic field
Define the Curie point
temperature at which certain magnetic materials undergo a sharp change in their magnetic properties
A rock below blocking temperature means that
the magnetized grains of a cooling rock cannot be reoriented
Define thermoremanent magnetization
The alignment of a cooling igneous rock’s magnetic moment to the direction of the earth’s magnetic field.
depositional or detrital remanent magnetization (DRM) vs chemical remanent magnetization (CRM)
DRM: Alignment of small grained detritus deposited in still water
CRM: acquired in situ after deposition during the chemical growth of iron oxide grains, as in a sandstone
Curie temperatures for Iron, Magnetite and Hematite
770◦C, 580◦C, 680◦C
What is Induced Magnetization
Magnetization of a rock induced by the earth’s magnetic field
What makes a triple juction stable
> plate motion and the position of boundaries does not cause the change of configuration over time
How are the Northern and Southern lights made
> changes in solar wind causes charged paticles in the van allen belts to enter the upper atmosphere
particles lose enery, electrons drop back to lower energy state, and releases light
What causes magnetic storms
Major sunspot activity causes changes in the solar wind, which in turn result in short-term fluctuations in the magnetic field
How can sedimentary rocks acquire remanent magnetization
by either DRM where grains aligns in still water as they deposit or CRM where developing iron oxides orients after rock formation.
Explain the Vine-Matthews Hypothesis
> strips of seafloor parallel to MORs are magnetized in opposite directions due to the magnetic reversals of the earth
How did geophysicists were able to track plate movement via paleolatitudes
> Rocks record the magnetic latitude on where it was formed
If that certrain rock moved it would have a different latitude from where it presently is
Basalt flow at 47◦N, 20◦E.
Angle of inclination = 30◦
Calculate the magnetic latitude of this site at the time the basalt was magnetized
tan I = 2 tan λ
tan 30 = 2 tanλ
λ = 16.1
Why is the study of triple junctions important
> provide valuable information about the geological evolution of regions over time
Earth’s Age
4.6 bya
upward swelling of soil due to the formation of ice during freezing conditions.
frost heave
great reduction in pressure that occurs
when the overlying rock is eroded away
unloading
curved or domed structures that form when layers of material are peeled off or separated in a non-uniform manner.
exfolation domes
the kind of fracture that is produced by contraction during the cooling of igneous materials, and tectonic forces during mountain building, often forming a definite pattern
joints
In chemical weathering, what do plant roots, fungi, and lichens produce that promotes decomposition?
Acids
What is the most important agent of chemical weathering?
Water
Most abundant products of feldspars
Clay minerals
A common boundary where different systems interact
interface
refers to the proportions of different particle sizes of soils
Soil texture
a layer of rock and mineral fragments produced by weathering
Regolith
Soil usually forms as clumps refered to as
Peds
Examples of external processes
Weathering, Mass Wasting, Erosion
Examples of internal processes
Orogenic and Volcanic Activity
Weathering?
physical breakdown (disintegration) and chemical alteration (decomposition) of rocks at or near Earth’s surface
Mass Wasting?
the transfer of rock and soil downslope under the influence of gravity
Erosion?
The physical removal of material by mobile agents such as water, wind, or ice
Mechanical Weathering?
accomplished by physical forces that break rock into smaller and smaller pieces without changing the rock’s mineral composition
Chemical Weathering?
involves a chemical transformation of rock into one or more new compounds.
Important processes that fragments rock
Frost wedging, salt crystal growth, sheeting, biologic activity
End points of the soil texture diagram
Sand, Silt, Clay
Differential Weathering?
The weathering of landforms in different rates due to composition, structure and resistance to weathering
Four basic soil structure (peds)
platy, prismatic, blocky, spheroidal
Residual soils v Transported soils
Residual : parent material is bedrock
Transported: parent material is loose sediment
What would be the general relationship of time to soil formation
> the longer a soil forms, the less it resembles the parent material
What would be the optimum terrain for soil development? Its opposite?
> flat to undulating upland surface
steep slopes
The basic controls of soil formation
> Parent material, time, climate, Plants and animals, topogrphy
The five horizons that forms the soil profile
O, A, E, B, C,
Why are weathering, mass wasting, erosion are considered as external processes
> occur at or near Earth’s surface and are powered by energy from the Sun.
Frost wedging process
> water can expand 9% when freezing
freezing water enters cracks
expands and enlarges cracks
Salt crystal growth process
> sea spray from breaking waves or salty groundwater penetrates rock crevices and pore spaces
water exaporateds and salt crystrals form
crystal growth pushes rock, weakening it
Sheeting process
> process generating onion like layers when large igneous rocks are exposed to weathering;
How do plant roots contribute to weathering by growing into fractures?
They wedge the rock apart
What is the role of burrowing animals in weathering
They break down rock by moving fresh material to the surface
What does chemical weathering involve in terms of altering minerals
Removing and/or adding elements to alter internal structures
What is the result of the transformation in chemical weathering?
Original rock decomposes into substances stable in the surface environment
The chemical equation for limestone dissolution
CaCO3 + CO2 + H2O –> Ca(HCO3)2
The vegetation at Mount Hamiguitan is a dwarf forest composed of miniature trees. What does it imply for soil composition and parent rock.
> the soil is composed of ferromagnesian minerals
parent rock is likely mafic in composition
How does the chemical weathering of granite lead to chert nodules
> silica dissolved by water
silica enriched water is transported and eventually precipitates in pore spaces of sediment grains
Why is quartz resistant to chemical weathering`
> Hardness of quartz in Mohs Scale (7)
Qtz is inert and chemically stable
Framework strcurture provides stability
Cassiterite chemical composition
SnO2
chalcocite chemical composition
Cu2S
chalcopyrite chemical composition
CuFeS2
cinnabar chemical composition
HgS
chromite chemical composition
FeCr2O4
% An of Bywotonite
70-90
% An of Anorthite
90-100
Calcic endmember of plagioclase
Anorthite
Sodic endmember of plagioclase
Albite
Cobalt Ores and chemical composition
Cobaltite, CoAsS
Linnacite, Co3S4
Smaltite, CoAS2
Erythrite, Co3As208-8H20
Iron Ores and chemical composition
Hematite, Fe2O3
Magnetite, Fe3O4
Goethite, FeO(OH)
Limonite, FeO(OH)-nH2O
Siderite, FeCO3
Shield Volcano characteristics
> gentle upper slopes ans steeper lower slopes
formed by low viscosity lava flows
non explosive eruptions
has a central vent
Stratovolcano characteristics
> steeper slopes (6-10 deg on flanks; 30 deg near top)
interlayering of lava flows and pyroclastic material
andesitic to rhyolitic in composition
Tephra Cones characteristics
> Small volume cones formed from tephra produced by strombolian eruptions
Basaltic to Andesitic
Cone slopes are controlled by angle of repose (25-35 deg)
Layered strucuture due to varying intensities of past explosions ans subsequent deposits
Maars characteristic
> Created from phreatic or phreatomagmatic eruptions,
Water is blasted by heated steam which forms a tephra cone with gentle slopes, resulting crater fills with water to form a lake
Lava Domes characteristics
> extrusion of highly viscous and gas poor andesitic-rhyolitic magma
lava piles up over the vent due to high viscosity
brecciated flanks
Crater v Caldera
> Craters: Circular depressions less than 1km, formed from explosions
Calderas: larger depressions, circular to elliptical, diameters ranging 1-50 km, formed from structural collapse
Mofette vs Solfatara
Moffette: fumarole that emits CO2
Solfatara: fumarole that emits sulfurous gases
Hotspring vs Geysers
Hotspring: areas where hot water surfaces
Geysers: a hotspring with a plumbing system that allows the accumulation of steam
Lava Dome vs Resurgent Dome
Lava domes: extrusion of viscous magma, piles up to form a dome
Resurgent dome: Resurging domes when magma is reinjected to existing calderas
Stoping vs Shouldering
Stoping: Host rock breaks into pieces and settles into the intruding magma
Shouldering: The explotation of mamga between layers of host rock, creating fractures
Explain the Phase Rule
> dictates the number of phases that can coexist in any system
P=C+2-F
P = number of phases
C = min number of chemical components
F = degrees of freedom or variance
Explain the Lever Rule
> used to locate positions on a phase diagram
SiO2 Polymorphs and respective crystal structure
Alpha Qtz - hexagonal
Beta Qtz - hexagonal
Tridymite - Monoclinic
Cristobalite - Cubic
Coesite - Monoclinic
Stishovite - Tetragonal
Exaplin the Three common types of equilibria
Invariant: neither P or T cant change
Univariant: P or T can be changed independently
Divariant: P and T are free to change without changing the stability of the system
How does basaltic magma form
-1000 - 1250 deg C
-partial melting of peridotite into basaltic magma
-triggered by a reduction in confining pressure (adiabatic melting)
-in subduction zones; water from descending slab promotes partial melting
How does andesitic magma form
- basaltic magma undegoes magmatic differentiation as it rises
- rising basaltic magma assimilate silica rich crustal rock
The mechanisms that leads to the development of Lopoliths
-meteorite impact and associated crustal melting
-normal faulting ang crustal melting
-a sill like structure that receives upwelling magma from a conical feeder tube,
How did volcanic necks form?
- ancient conduit pipes that funneled magma upward to a volcano that has long since been removed by erosion.
Why is columnar joinitng in basalts possible
- contraction of lava as it cools
- formation and development of cracks perpendicular so surface
- slower cooling rate at bottom; fgaster at top
The IRR of RA 9275
DAO 2005-10
Provides the legal framework for the establishment and mangement of protected areas in the PH
RA 7586
The section in the Constitution which states the protection and right of the people to a balanced and healthful ecology
Section 16, Article 2
What doctrine does the PH has in regulating mineral resources
Regalian Doctrine
a global agreement to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances
Montreal protocol
RA 8371 is also known as
Indigenous people act of 1997
RA 7942 is also known as
Philippine Mining act of 1995
RA 7076 is also known as
People’s Small-scale Mining Act of 1991
What is the Revised Implementing Rules and Regulationg of RA 7942
DAO 2010-21
Briefly explain the primary objective of the RA 9275
To protect the waterbodies of the PH and ensure acess to clean water for Filipinos
Enumerate the Freshwater classifications under DAO 2016-08 and briefly explain
Class AA : unhinhabited watersheds and declared protected areas
Class A: suitable potable water
Class B: safe for recreational activities
Class C: aquaculture, irrigation and livestock watering
Class D: navigable waters
Categories of Protected areas under NIPAS law
Strict Nature Reserve
Natural Park
Natural Monument
Wildlife Sanctuary
Protected Landscapes and Seascapes
Resource Reserve
Natural Biotic Areas
What is the Regalian Doctrine in the contect of mineral resources
A doctrine that espouses that the state is the sole owner of the mineral resources found in its territory
Ancestral Doman VS Ancestral Land
Ancestral Domain: all areas generally belonging go ICC/IPs communally or individually since time immemorial continually to the present
Ancestral Land: land occupied, possessed and utilized by ICC/IP individuals, family and clans since time immemorial
What does FTAA stand for
Financial Technical Assistance Agreement
What does MPSA stand for
Mineral Production Sharing Agreement
Explain the concept of Free & Prior Informed Consent
consent obtained that is free from coercion, manipulation or intimidation
consent that is sought in advance of any activities/decision
individual/members had adequate and timely information about the proposed activity/decision
Areas closed to mining applications
Protected areas under NIPAS law
Old Growth/Virgin Forests
Forest and other government reservations unless with clearance
Built up Areas
Ancestral Domains/Lands unless with FPIC from IPs/ICCs
Other areas espressly prohibited by law
Kinds of Mineral Agreements
Mineral Production Sharing Agreement (MPSA); Co-Production Agreement (CA); and
Joint Venture Agreement (JVA)
How would a Sand and Gravel Permit issued by DENR-MGB differ from one that is issued by the LGU
The hectare of the project area issused by the DENR-MGB would be 5-20 ha while LGU can only give permits for less than 5 ha
What are the kinds of tenements issued by the DENR-MGB
- Exploration Permit (EP)
- Mineral Agreements
- Financial or Technical Assistance Agreements (FTAA)
- Mineral Processing Permits (MPP)
- Industrial Sand and Gravel Permits (>5 to 20 hectares)
- OTPs/MOEPs
How does other agencies work with the main institutional mechanism in implementing the clean water act
DPWH: sewage + sanitation facilities
Coast Guard: enfore quality standards in marine envi
DA: agricultural wastewater management
DOH: formulate revise and enforce quality drinking water standards
DOST: pollution prevention and production tech
How would the government encourage private sector participation in preserving the water resources
Section 21 of RA 9275 mandates LGUs to come up with incentives for proceedures/technologies that would will preserve and protect our water bodies
How does the ENIPAS act improve upon the NIPAS act.
Newer Classifications for national parks (94 vs 13)
Inclusion of private lands as buffer zones
Adminstration and mangement by BMB rather tan PAWD
E-nipas includes land and water use plans while nipas only includes land use plan
All projects/activities whether or not included in the mngt plan must have EIA under the E-nipas
E-nipas would give more rights to ICC/IPs
A landower is under scrutiny by a certain IP community due to conlifcting claims of a certain area. According to IPs it belonged to them since it is a part of ancestral land. However, the land was already titled prior to is declaration as an ancestral land. Which claimant would have the better claim and why.
The landowner since the area was already titled to him. Ancestral Domain/Land is only applicable to areas without a tite.
A significant Cu-Au porphy is discovered on a certain area which promts Company A to make plans to mine the area in the forseeable future. However, portions of that area is wihtin an ancestral domain. How could the mining company legally conduct mining activities with these conditions in mind.
The mining company would at least pay a set amount of royalties to the owning IP/ICC
The said company needs to have free and prior informed consent from the IP/ICC along with other social corporate responsibilities in order for a mining permit to be issued.
A certain Juan aspires to make a difference in the mining industry. To do that he/she must at least be a Qualified Person. What would qualify him/her as one?
-Filipino Citizen
-Legal age
-financially and technically capable
What factors would make mining activities as responsible
development of the country’s mineral resources is based on technical feasibility, environmental sustainability, social acceptability, and financial viability.
In what situations would a FTAA be more preferrable than a MPSA?
-100% owned by a foriegn corporation
-area not more than 81 000 ha onshore or 324 000 offshore
-large scale exploration exploration, development and utilization of mineral resources. Usually with techonologies beyond the capabilities of local companies, hence the bidding of foreign ones.
Under the RA 10121, which agency would take the lead in a disaster and under which criteria
Barangay Affected: BDC
Multiple Brgy: CDRRMC/MDRRMC
Multiple Municipalities/Cities: PDRRMC
Multiple Provinces: Regional DRRMC
Multiple Regions: NDRRMC.
