A research presentation framework• Title, authors, affiliation • Abstract • Introduction • Previous work • Methods • Results • Discussion • Conclusions• Acknowledgements• Bibliography• Glossary

How to write a paper or organize a presentation

Most journal-style scientific papers are subdivided into the following sections: Title, Authors and Affiliation, Abstract, Introduction, Previous Work, Methods, Results, Discussion, Acknowledgments, and Literature Cited, and maybe a glossary if technical terms are used.

Metamorphic Zones in the Eastern Scottish Dalradian

George Barrow, BAKings College London

April 28, 2014

TitleWhat paper is aboutwhere, when it formed

Authors namesUniversity affiliationDate of presentation

Abstract• From 1884 to 1900 I conducted field work on metamorphic

rocks in the region south of Aberdeen. Rock samples were collected and thin sections were prepared for three SE to NW transects of thin outcrops of metamorphic rock types. Based on these studies, I recognized five metamorphic zones based on the first appearance of five minerals: Chlorite (adjacent to the Highland Boundary Fault) , Biotite, Garnet, Kyanite, and Sillimanite. The chlorite zone was furthest from granite and gabbro intrusions in the Dalradian, and the grade increases in the above order to the Sillimanite zone adjacent to the intrusions.

When, on what, where, methods, results, why

Introduction

• From 1884 to 1900 I conducted field work on metamorphic rocks in the region south of Aberdeen. Rock samples were collected and thin sections were prepared for three SE to NW transects of thin outcrops of metamorphic rock types.

Previous Work• Barrow would write: In 1910, Grubenmann advanced the hypothesis of the threefold division of the

earth’s crust into depth zones distinguished by the nature of the metamorphic processes: the kata, meso, and epi zones. These terms have been retained to the present but are used to designate not so much the depths of rock occurrence as the grades of metamorphism.

• Harker (1918) thought that crust pressure increases downward [along] with increasing temperature. He further thought that the maximum shearing stress a rock can withstand decreases with increasing temperature, so temperature is the only independent variable that controls regional [dynamothermal] metamorphism (Miyashiro (1994)). He thought that my earlier papers on the Dalradian (Barrow (1910) ) were examples of this type of metamorphism. Harker further thought that strong shearing stress produces such characteristic minerals as chlorite, almandine garnet, staurolite, and kyanite.

• On the other hand, Harker thought that the absence of stress in contact metamorphism produced such characteristic minerals as andalusite and cordierite.

• YOU WOULD WRITE ABOUT Volkert and Drakes opinions, discussions on the Cranberry Lake Map (“Stanhope Quadrangle”), the distribution of rocks and faults the mappers found, the minerals they found, what they thought the parent rock was and why, and later tests of their ideas, as well as any new ideas.

• YOU would also display and explain any pertinent tables or graphs related to the origin of your rock in the papers you found. For example, from Volkert and Drake

Use Cassi’s paper on additional laboratory tests of a Tonalite/Dacite origin for the Losee as a model for the type of previous work papers you are looking for.

The Dalradian Supergroup is a complex of metapelites bounded by the Highland Boundary Fault to the southeast, and by the Great Glen Fault to the Northwest.

The field area is in the northeast portion of Scotland.

Field Area Previous Work

You have much better previous work maps

These need to be labeled and cited in biblio, one is Stanhope Quad, other is NNJ Geologic

Keep the symbol box, but type out the description

Previous work Losee Ylo• Volkert and Drake (1999) plotted mineral modal analyses for

three types of Losee Orthogneisses. Potassium Feldspars were uncommon. Plagioclases were abundant and plotted nearer to the Albite end member. All Losee samples plotted in the Tonalite to Trondhjemite fields. ADD other papers results after this

Puffer, J. H.; Volkert, R. A. (1991) Generation of trondhjemite from partial melting of dacite under granulite facies conditions: an example from the New Jersey Highlands, USAPrecambrian Research, 51: 115 – 125http://pubs.er.usgs.gov/publication/70016646

Their discussion went like this: “New field and geochemical data place the Losee Metamorphic Suite (a tonalite/trondhjemite complex) of northern New Jersey into the context of a major Proterozoic Continental Arc represented by a discontinuous belt of northern Appalachian metadacite. Samples of Losee rock range from extremely leucocratic trondhjemite locally associated with amphibolite, to banded biotite, hornblende, pyroxene, and garnet-bearing tonalites. The major element and REE composition of the tonalite closely resembles dacite from continental are settings and model melts extracted from an eclogite residue by partial melting at 15 kbar. The REE composition of most Losee trondhjemite is enriched in REE, particularly HREE, compared with Losee tonalite, and is interpreted as the product of local anatectic melting of Losee tonalite (metadacite) that occurred in a granulite facies environment during the Grenville orogeny.”

USUALLY YOU WOULD SUMMARIZE ON A POWERPOINT SLIDE, with cues to remind you what to say.

Bibliography entry looks like this

Previous work Ymp

• Ymp metasediment• Volkert and Drake C13-C15 Fig. 12 and Table 8 .

“Clinopyroxene-quartz-feldspar gneiss [author: Ymp] typically contains 60 to 75 weight percent SiO 2, 10 to 14

weight percent Al2O3, 1 to 6 weight percent CaO, and appreciable Na2Oand K2O (table 8). This gneiss is slightly higher in CaO than hornblende-quartz-feldspar gneiss (table 7), but their major- oxide contents are otherwise similar. In figure 12, clinopyroxene-quartz-feldspar gneiss [Ymp] spans the fields of arkose, lithic arenite, and graywacke, reflecting variability in the sedimentary protoliths.” In other words, mixed sandstones

Previous work Ymp

Methods• Large hand samples were collected and thin sections prepared for localities from

(choose: A leucocratic Granulite “Losee Gneiss Ylo”; A Microcline-Clinopyroxene-Quartz Gneiss” metapsammite Ymp).

• Rock samples were cut in half on the _____ diamond saw. Half was relabeled and retained as a reference specimen and for photography, the other half cut into a 1 cm slab for thin sections. The slab was divided, relabeled, and marked for oriented thin sections. One specimen was sent to National Petrographic Services, Houston, for thin section preparation. The other half was prepared as a thin section in our lab using the Ingram thin section machines.

• Thin sections were examined on the Leitz and Olympus petrographic microscopes, then photographed and videographed under plane polarized and cross polarized light. Linear counts were made in 10 regions of each slide or photograph for Quartz, Plagioclase, Potassium Feldspars, Orthopyroxenes and Clinopyroxenes, Amphiboles , Micas, and Garnets.

• The counts were then converted to percent volumes.• Plagioclase compositions were calculated using the method of Michel-Levy

Extinction plots.• Based on these and plots of laboratory data from similar rocks, possible parent

rock types were determined

Both granitic and gabbroic intrusions caused the metamorphism discussed in this report.

The Chlorite zone is furthest away, followed by the biotite, garnet, kyanite and sillimanite zones.

RESULTS

Sequence of zones, typical mineral assemblage Chlorite zone. The metapelitic rocks are slates or phyllites and

typically contain chlorite, muscovite, quartz and albite Biotite zone. Slates give way to phyllites and schists, with biotite,

chlorite, muscovite, quartz, and albite Garnet zone. Schists with conspicuous red almandine garnet,

usually with Biotite, chlorite, muscovite, quartz, and Albite or Oligoclase

Kyanite zone. Schists with Kyanite, Biotite, Muscovite, Quartz, plagioclase, and usually garnet and Staurolite

Sillimanite zone. Schists and gneisses with Sillimanite, Biotite, Muscovite, Quartz, plagioclase, garnet, and perhaps Staurolite. Some Kyanite may also be present. Kyanite and Sillimanite are both polymorphs of Al2SiO5)

RESULTS

Chlorite Zone

Chlorite Zone along the Glen Esk River

http://www.esci.umn.edu/orgs/whitney/Barrovian_sequence.htm

Field Photographs• Barrow had many more areas than you have

Biotite Zone

Biotite Zone along the Glen Esk River

http://www.esci.umn.edu/orgs/whitney/Barrovian_sequence.htm

Garnet Zone

Garnet Zone along the Glen Esk River

http://www.esci.umn.edu/orgs/whitney/Barrovian_sequence.htm

Kyanite Zone

Kyanite in the Kyanite Zone

http://www.esci.umn.edu/orgs/whitney/Barrovian_sequence.htm

Sillimanite Zone

http://www.esci.umn.edu/orgs/whitney/Barrovian_sequence.htm

In the Sillimanite Zone

Thin Section Studies

• Barrow had multiple thin sections for each zone.

• You provide multiple views in one section• These will be the basis for your modal

analyses.

Chlorite Zone The Chlorite zone metapelites typically contained chlorite, muscovite, quartz and albite

Biotite Zonephyllites and schists, with biotite, chlorite, muscovite, quartz, and albite

Biotite Muscovite and Quartz

Garnet ZoneSchists with conspicuous red almandine garnet, usually with Biotite, chlorite, muscovite, quartz, and Albite or Oligoclase

Garnet-Mica Schist

Kyanite ZoneSchists with Kyanite, Biotite, Muscovite, Quartz, plagioclase, and usually garnet and Staurolite

Sillimanite Zone Schists and gneisses with Sillimanite, Biotite, Muscovite, Quartz,

plagioclase, garnet, and perhaps Staurolite. Some Kyanite may also be present.

Modal Analysis Methods• In as many microscope fields of view as you can manage

(magnification is Objective x eyepiece power) count the common mineral phases visible, calculate a multiplier, and get a % for each.

• For the Losee count quartz, plagioclase, garnet etc in the commercial slide. Determine and also count mafics for the slide we made.

• For Ymp count Microcline (tartans) , clinopyroxenes (higher int colors), Quartz (und .ext.) and Oligoclase (near Albite) plagioclases.

Ymp Published Lab Results

• 2. Ymp metasedimentsSample “692—Titanite [aka Sphene]-clinopyroxene-quartz-feldspar gneiss. [the remark “Interlayered with clinopyroxene-hornblende-plagioclase amphibolite” –THIS IS NOT IN YOUR SAMPLE]. North side of draw between ridge crests, Allamuchy State Park, 0.50 mi south of Strawberry Point, Cranberry Lake; Stanhope 7.5-min quadrangle.” This is the place we went to just south of your collection locality. We decided it looked exactly the same.Compare your mineral findings to this sample

Plot sample 692 on this. Use the oxides.

Conclusions: Parent Rock

• Discuss possible protolith sources for your respective rock.

Acknowledgements

• I thank my fellow geologists, J.B Hill, L.W.Hinxman, J. Horne, J.Linn, B.N Peach, H.Mitter, and W. Gunn. for helpful comments and help in the field and laboratory.

Literature Cited• George Barrow didn’t have much of a literature or geologic maps to refer to.• Grubenmann, Ulrich (1910) Die kristallinen Schiefer, 2nd ed., parts 1–2. Berne.• Harker, Alfred (1910) Geology for Students

• You have a vast literature at your disposal. An example citation:• 1. Puffer, J. H.; Volkert, R. A. (1991) Generation of trondhjemite from partial melting of dacite

under granulite facies conditions: an example from the New Jersey Highlands, USA Precambrian Research, 51: 115 – 125

http://pubs.er.usgs.gov/publication/70016646

2. Volkert, Richard A. and Drake, Avery (1999)Geochemistry and Stratigraphic Relations ofMiddle Proterozoic Rocks of the New Jersey HighlandsU.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1565–C. 77 pages.http://pubs.usgs.gov/pp/p1565c/p1565c.pdf

• If you have too much, you may wish to limit your literature discussions to studies that pertain to rocks most similar to your project rock and slide.