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Dr.Thrivikramji.K.P.thrivikramji@gmail.com

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Light bulb

After: Hochella Jr. (2008)

Scale in Nanoscience

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Laterite profile, ThenmalaWeathering of Charnockite

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Microcline dissolution

Dissolution of ilmenite,OffshoreDissolution of ilmenite,Offshore

Progressive weathering

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Etch pits:

a. Hypersthene,

B Hornblende

C Augite

D Augite

AJSci,282, Oct.1982

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A S-s Hy

B e-e, Dio

C s-s Aug

D e-e Aug

All etch pits

B AJSci,282, Oct.1982

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AugiteDiopside

Hornblende Hornblende

AJSci,282, Oct.1982

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AugiteHornblende

Clay in Hyp Clay in HbCourtesy: AJSci,282,Oct.1982

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Carbonate cement

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Opy to TalcA,B&C Opy to Talc

D&E Opy to Smectite

AJSci,282, Oct.1982

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OPy to Smectite and Talc AJSci,282, Oct.1982

13Weathering of Opy to amorphous material

AJSci,282, Oct.1982

14Random Aggregation of pyrite, Veli Kayal, Tvm (1992)

15Pyrite framboid, Cretaceous Austin Chalk, Texas, coll. B Woods (Folk, 2005)

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The LycurgusCup- The Roman nano-technology.Tiny amounts of colloidal gold and silver in the glass gives a dichroicproperty- green in day light & red under candlelight.

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vary

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NANOSCIENCE plays out in

the critical zone of the Earth. Jordan (2001) defines in a NRC book entitled Basic

Research Opportunities in Earth Science , as the place where the land meets the fluid

envelopes of the Earth, i.e., the hydrosphere & atmosphere. Fresh water, agriculture & many vital natural resources such as most mineral

deposits & timber are here. Geo & bio aspectsmake it most heterogeneous.

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Based on Physical, geochemical, and biologic processes, four principal & overarching categories identified.

1) biologic2) weathering,

3) fluid transport, &4) near-surface tectonics.

Boundary of Nanogeoscience & life science fuzzy.

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1) Biologic Activity: Due to organism s nutritional

requirements, drives a significant amount of chemical cycling within & between

water, soil, rocks &atmosphere; 2) Weathering:

Constantly at work in the critical zone, generating soil, destroying & producing minerals in the process & redistributing elements among water, rocks, & organic

materials

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3) Fluid transport: the critical component in water

resources supply & management, as well as everything from flooding to

landform development4) Near-surface tectonics:

shapes the land surface through faulting, subsidence, uplift & mass

movement

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Transport of metals & organics in near surface environment;

Global geochemical & climate cycles (+carbon);

Ore genesis & exploitation; soil science; microbial geochemical action; origin of life; space weathering & planetary

surfaces; aerosol transport & ice nucleation; even deep earth processes.

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Nanoscale phenomena involving nano-sized geomaterials-

Processes of elemental distribution; Biologic abiotic Earth interaction; Heterogeneous catalysis; Reaction pathways & mineral growth; Mineral

Transformation & weathering.

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Where are Nanominerals & mineral nanoparticles?

Noticed widely & commonly in atmosphere, oceans, ground &

surface waters & soils.Also in/on most living organisms &

even within proteins like ferritin- iron storing protein in body tissue.

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Why Nanogeoscience?Nutrients limit Oceanic Productivity;

Iron a chief nutrient, reaches ocean as dissolved inorganic and organic

complexes..Nanoparticles of 2 to 20 nm range

has good amount of iron.Oceanic Iron flux via Fe-containing nanoparticles far exceeds riverine

input. Phytoplankton does 50% photosynthesis

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Importance of Nanogeoscience1. Iron in mineral nanoparticles is bioavailable to various species of marine phytoplankton making them more important source of Oceanic iron.

2. Also in toxic-metal transport in Earth s near-surface terrestrial environment - Radionuclide transport by groundwater over several kilometers in short periods of time defies thermodynamics based predictions

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Importance of Nanogeoscience

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Why Nanogeoscience?Contamination of an area of 1600 km2 by

Cu, Zn, As, Pb, and Cd due to 11/2 century of mining - the largest Superfund site - in

western Montana,USA. Metals moved many hundreds of km down

the hydrologic gradient & across floodplains in the Clark Fork River basin.

Carried chiefly by nanominerals and mineral nanoparticles of manganese and iron oxyhydroxides (Hochella et al. 2005).

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Nanogeoscience, Why?Currently mechanical properties much less studied; so impact on working of Earth less

known; so an area of exciting future research in mineralogy.

Natural production of mineral nanoparticles by mechanical grinding associated with earthquake-

generating faults in shallow crust & Earth s surface is known.

Large volumes of mineral fragments of 10 20 nm in size noticed in pulverized rock in fault zones of

up to 100 m width. Suggesting importance of mineral nanoparticles in fault mechanics

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Why Nanogeoscience ?Nanoparticles of high-pressure silicates (e.g., ringwoodite and wadsleyite) may have key role in deep-focus earthquakes (300 700 km depth) in Earth s mantle.

Mineral nanoparticles fill anticracks (planes of weakness that need not dilate to make empty space), in contrast to a normal crack.

As nanoparticles easily move past each other without mechanical shearing of individual grains (like talc) high pressure does not restrict the movement.

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NATURAL AMORPHOUS NANOMATERIALS

Far less known due to:Limited diffraction informationHard to interpret Spectroscopic

measurements Highly variable chemistry and formBut growing recognition of natural

abundance and importance.

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1.Zhu et al. (2006) reported thick amorphous silica-rich (leached from feldspar or from ground water)

layers of nanofilms (10 50 nm) on feldspar surfaces in the Jurassic Navajo Sandstone, Black

Mesa, Arizona, USA.

Weathering rate of K-feldspars is 10E5 times slower under natural conditions than under

similar conditions in weathering experimentsNanofilm study explains difference the rate

weathering in the lab and under nature.

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TL, K feldspar grain-amorphous over layer , 10-50 nm thick; TR, Weathered basalt with clay precursors; BL- Zn sulfide nanoaggregates, Clark fork River bed sediment, Montana (After:Hochella,2008)

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Several year-long leaching experiments:

Amorphous nanofilms on uranium-containing pyrochlore (a calcium

titanate considered for immobilizing fissile elements), slows release of U

(Stubbs et al. 2008). May play a crucial role in dictating

uranium s mobility through the vadose zone

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The Clark Fork riverbed and Floodplains, MoReducing zones of river bed with amorphous, aggregated Zn-sulfide nanoparticles.Their environmental role almost completely unknown a research opportunity.

Amorphous, metal-bearing, naturally occurring nanomaterials still undocumented or completely unknown.

Recent studies showed secondary amorphous silica with toxic heavy metals are relatively common.

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NANO-MATERIALS OUTSIDE EARTH:(

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Chondritic meteorites & Interplanetary Dust Particles.

Diamond nanoparticles of average 2 to 3 nm dia and grains as small as 1 nm

(<150 carbon atoms) in minute quantities.

Nanodiamonds separated by multistepacid digestion process or burning

down the haystack to find the needle .

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Nanopores and Mesopores?

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A vast array of structures & mechanisms symbolize Inorganic nanosystems (+ living

things).Nanoscale physics & chemistry basis of

Nanobiomachines (molecular motors). For better knowledge of inorganic systems and to better appreciate nanogeo and nanobio

interactions.Better perception of

characteristics and behavior of natural nanoscale biological properties.

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Highly confined pores & tubes greatly modify mineral fluid interface reaction

pathways & kinetics compared to reactions at unconfined mineral fluid

interfaces. Such changes affect sorption, desorption and diffusion,

greatly affecting precipitation, weathering & transport phenomena.

(e.g. Hochella and Banfield 1995; Wang et al. 2003).

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Surface charge, cluster growth characteristics, stability & fluid dynamics

principles dictate aggregation/dis-aggregation behavior of natural

nanoparticles in air & water (e.g. Gilbert et al. 2007).

A combination of experiments & modeling will help researchers to infer the characteristics & behavior of the

nano-aggregates.

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The mineral kingdom is more complex than previously thought. Nanogeoscience is at a relatively early stage of development, and

large gaps exist in our knowledge. The next few years and decades will

be an exciting time of new realizations, discovery, and change .

(Hochella JR, 2007)

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TL- High-resolution TEM images of 2 3 nm nanodiamonds recovered from the Murchison meteorite; TR - interplanetary dust particles (After: Hochella Jr, 2008)

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Potential applications of nanoscience

include: ultra-small sensors & devices, including transducers for

force, pressure & chemical compounds; molecular gears,

motors & actuators. Now is the time to plan

for applications & shape the future with

groundbreaking innovations

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62Pyrite Framboids of cube-octahedron crystals

63Pyrite Framboids of octahedron crystals

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66Folk (2003)

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Folk (2003)

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Folk ( 2003)

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Folk (2003)

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