Authors: Robert M. Garrels Fred T. Mackenzie 1/20/10.

Slides:

Advertisements

Similar presentations

Phase Diagram for Water

Advertisements

GY1004 Principles of Physical Geography B

Dissociation and pH Dissociation of weak acids/bases controlled by pH Knowing the total amount of S and pH, we can calculate activities of all species.

Sub-solidus evolution. Mineral transformations Secondary minerals Fluids expulsion and movement –Pegmatite/aplite veins –Mineralized veins Hydrothermal.

Dissolution and Precipitation

Class evaluations.

Minerals A. Changing scales to looking at the elements of the earth and its crust (8 most common) B. Introduction to minerals that comprise rocks (11 most.

Six-sided, pyramidal Quartz Crystals.

Soil Chemical Properties

Sedimentary Materials

Redox and Eh From electrochemistry:  G R = -nF Eh – E° = -  G R ° / nF – For e - on left side of half-reaction; – If e - on right side: E° = +  G R.

Weathering Types: Physical or mechanical (increases surface area) Chemical (chemical transformations) –Congruent (complete dissolution) –Incongruent (solids.

Inverse Mass-Balance Modeling versus “Forward Modeling” How much calcite precipitates? 2% CO 2 atm CO 2 Forward Approach What is the strategy? What data.

Early martian surface conditions from thermodynamics of phyllosilicates Vincent F. Chevrier Workshop on Martian Phyllosilicates: Recorders of Aqueous Processes?

Atoms are the smallest components of nature

Lecture 9 – What Controls the Composition of Seawater

Summation of Biogeochemical Research of Sierra Nevada catchments Kate Samelson Kendra Morliengo-Bredlau Ben West Corey Lawrence.

Dissolution and Solubility Processes Dissolution-precipitation equilibria affect many soil processes, plant growth, etc Dissolution is the disintegration.

GES 430 Environmental Geochemistry Class 6 Acidity, Alkalinity + Buffering.

Atoms, Compounds, Minerals and Rocks. Atoms Atoms - the smallest unit of an element that retains the physical and chemical properties of that element.

Ch 5 – Weathering & Erosion

Bowen’s Reaction Series

1. Dissolved Inorganic Carbon (DIC) Initially, DIC in groundwater comes from CO 2 – CO 2(g) + H 2 O ↔ H 2 CO 3 ° – P CO2 : partial pressure (in atm) –

Chemical Weathering. I. Introduction Chemical Weathering I. Introduction II. Process of Decomposition A. Overview: Decomposition alters minerals into.

Acid-Base Reactions and Proton Accounting Lecture 20.

Rick's Cafe in Jamaica Keith Fairbrother Erosion Door County, WI Lizzy Schneider.

1 SGES 1302 INTRODUCTION TO EARTH SYSTEM LECTURE 14: Rock Cycle & Magmatism.

The name of biotite comes from the French physicist J. B. Biot

Weathering Mechanical Weathering Chemical Weathering Biological Weathering.

Chapter 3- Weathering Processes Two major categories Mechanical (or Physical) processes physical breakdown of larger particles into smaller particles Chemical.

Figure 9-1. Schematic representation of the hydrologic cycle. Numbers in parentheses are the volume of water (10 6 km 3 ) in each reservoir. Fluxes are.

MINERALS. Chemical composition of the Crust n Oxygen most abundant- 46.6% n Followed by silicon and aluminum n Iron, Calcium, Sodium, Potassium, Magnesium.

Chapter 4 – The Lithosphere Lithosphere (soils) affected by… composition of atm. gases (e.g. 4Fe  2Fe 2 O 3 ) atmospheric circulation climate.

Who Wants to be a Super Millionaire? IGNEOUS PROCESSES AND IGNEOUS ROCKS IGNEOUS ROCKS Cooled and crystallized from molten rock. Can occur at surface.

RIVERS: Major Components 1) water 2) suspended inorganic matter - major elements are Al, Fe, Si, Ca, K, Mg, Na and P 3) dissolved major spp. - HCO 3 -,

Soil Origin and Development

Ionic radius is related to the valence of the ion - ions that have lost electrons (cations) are smaller than their neutral state, ions that have gained.

Igneous rocks are further classified according to; Describes the appearance of an igneous rock, based on the size, shape and arrangement of interlocking.

Chapter 4 Magma, Igneous Rocks and Intrusive Activity

In general… High-temperature minerals + water = weathering products + dissolved ions Hydration/hydrolysis reactions. Depend on pH – acid vs. alkaline.

Mineral Colloids Continued. Na + K + K + Na + K + K + K + Cation Exchange Na +

Sedimentary Materials Sedimentary rocks cover 80% of the earth’s surface but only comprise ~1% of the volume of the crust (they are generally NOT dense.

Why is the ocean salty?. Rainfall and Rainfall Types Frontal Orographic Convective.

Chapter 9 Minerals Section 1 What is a Mineral? Notes 9-1.

Introduction to the Mineral Exploration Activity.

Fig 5.12 WHERE DO SEDIMENTS ORIGINATE? WEATHERING OF PRE-EXISTING ROCKS.

Mechanical Weathering

Igneous Rocks Intrusive and extrusive rocks formed from the cooling and crystallization of magma.

Solubility (cont.); Mineral Surfaces & Reactions Lecture 22.

Bjerrum plot showing the activities of inorganic carbon species as a function of pH for a value of total inorganic carbon of mol L -1. In most natural.

Soil Clay Minerals and CEC

Silicate Clays.

Three Types of Rock: Igneous, Sedimentary, Metamorphic Rock: A solid, cohesive aggregate of grains of one or more MINERAL. Mineral: A naturally occurring,

VolumeMass Crust 1% 0.5% Mantle83%67% Core16%32.5% (Outer core)15.5%31% (Inner core) 0.7% 1.5%

Physico-chemical and isotopic composition of some lakes and springs in the Bamenda Highlands, North West Cameroon Cameroon Japan CVL8 Workshop, July 28,

MINERALS ARE EVERYWHERE. WHAT IS A MINERAL? All Minerals share the following 5 characteristics: Naturally occurring: a mineral forms by natural geologic.

TRACE METAL TRANSFER FROM ROCKS TO THE PEDO- AND HYDRO- SPHERES.

Chapter 2 Minerals Section 1 & 2 Matter and Minerals Notes 2-1.

Soil Chemistry.

III. Atoms, Elements and Minerals

Lecture on Minerals

What are the 2 ways rocks are Weathered?

Figure 9-1. Schematic representation of the hydrologic cycle

Ocean chemistry strongly linked to land (chemical weathering),

Chemical Weathering SAPROLITE.

Set the composition of the initial fluid on the Basis pane.

Estimating Mineral Weathering Rates in Catskills Watersheds

Sedimentary Materials

Activity diagram showing the stability relationships among some minerals in the system K2O-Al2O3-SiO2-H2O at 25°C. The dashed lines represent saturation.

Presentation transcript:

Authors: Robert M. Garrels Fred T. Mackenzie 1/20/10

Introduction This paper explores the origin and composition of springs in the Sierras. -Sierra Nevada setting was chosen b/c of availability of careful water and soil analyses by Feth, et al. -Granitic rocks high in Feldspars, and quartz Two parts to this paper: -Weathering process/analysis, and reconstruction of original rock from observed dissolved solids -Evaporative concentrations of Sierra waters

-Sierra Nevada setting was chosen b/c of availability of careful water and soil analyses by Feth, et al. -Granitic rocks high in Feldspars, and quartz

Igneous rocks + soil waters This weather system is assumed to be closed, so there is little loss or gain of C02 or H20. Soil minerals + spring water

Composition of Ephemeral and Perennial Springs

Reconstruction of original materials Back react spring water w/ kaolinite (chief weathering product) and see if original rock minerals can be formed Cations and anions in snow water are removed from spring H2O solutes. ALL Na and Ca, and some HCO3 and Si02 react w/ kaolinite to form Plag. ALL Mg, and some K, HCO3, and Si02 react with kaolinite to form biotite, and k-spar.

Qualitative Aspects of weathering process -More silica in H20 than from only the breakdown of plag. Comes also from quartz, and the silica represents CO2 changed into HCO3 from weathering. -SiO2 and Aluminum concentrations and pH are reasonable for an alumino-silicate of the appx. stability of kaolinite. -80% of the dissolved solids in the ephemeral springs can be accounted for by the breakdown of plag.

“Pick up” of constituents by continued, deeper circulation A better idea of weathering occurring after initial “strong attack”, can be derived from subtracting out the ephemeral analyses from the perennial

- Next, Mg2+ and K+ are “used up” with kaolonite to from biotite mica and K-spar. - The remaining SiO2 was apportioned b/t reconstruction of both kaolinite and montmorillonite to plagioclase. -Considerable amounts of Ca2+ and HCO3- remain. It is postulated that during deep circulation the waters have lost their original aggressiveness and start to pick up Ca2+

Paths of water evolution

This was a great a analyses, but Garrels et al. want to take into account what occurs when springs are isolated from the parent rock and allowed to evaporate isothermally in equil. w/ the CO2 of the present atmosphere.

Evaporation changes water from a neutral Na-Ca-HCO3 to highly alkaline Na-HCO3-CO3

-Dissolved silica derived from incongruent solution of silicate minerals -Waters in equil. w/ atmosphere will eventually become highly alkaline if concentrated greatly

References Feth, J. H., Roberson, C. E., Polzer, W. L., U.S. Geol. Surv. Water Supply Paper , 170 (1964) Garrels, R. M., Mackenzie, F. T. Origin of the Chemical Compostion of Some Springs and Lakes