Petrographic, Geochemical, and Geophysical Well Log Assessment of the Precambrian Basement in Eastern Ohio a Thesis Presented To

Home , Syenogranite

Petrographic, Geochemical, and Geophysical Well Log Assessment of the Precambrian

Basement in Eastern Ohio

A thesis presented to

the faculty of

the College of Arts and Sciences of Ohio University

In partial fulfillment

of the requirements for the degree

Master of Science

Eric W. Gibbs

August 2020

This thesis titled

Petrographic, Geochemical, and Geophysical Well Log Assessment of the Precambrian

Basement in Eastern Ohio

ERIC W. GIBBS

has been approved for

the Department of Geological Sciences

and the College of Arts and Sciences by

Daniel I. Hembree

Professor of Geological Sciences

Florenz Plassmann

Dean, College of Arts and Sciences 3

ABSTRACT

GIBBS, ERIC W., M.S., August 2020, Geological Sciences

Petrographic, Geochemical, and Geophysical Well Log Assessment of the Precambrian

Basement in Eastern Ohio

Director of Thesis: Daniel I. Hembree

This study evaluated the use of geophysical well logs to interpret igneous and metamorphic lithologies from the Precambrian basement in east-central Ohio.

Geophysical well logs are a staple of the oil and gas industry, but are designed and calibrated for use in sedimentary rocks. Thin-section petrography and X-ray

Fluorescence were used to analyze 13 and 16 basement sidewall core samples, respectively, from two wells in Noble and Coshocton counties. The samples were separated into two broad groups on a standard Quartz-Alkali-Plagioclase plot. The Noble county samples were predominantly syenogranites with minor monzogranite and quartz syenite. The Coshocton county samples were more mafic falling into the tonalite, quartz gabbro/anorthosite, and diorite/anorthosite fields. The responses of a suite of geophysical well logs from both wells were compared to the geochemical data in order to determine whether or not the tool response could identify the different crystalline rocks. Gamma- ray, bulk density, and photoelectric logs were used due to their distinctive responses in sedimentary rocks. Mann-Whitney nonparametric comparisons of well responses showed that the gamma-ray and bulk density responses could delineate lithologies whereas the photoelectric log values could not.

DEDICATION

To my mother, for allowing my childhood self to chisel rocks from our sidewalk. 5

ACKNOWLEDGMENTS

I would like to express many thanks to Eastern Mountain Fuel for providing the sidewall core sample materials and geophysical well logs used in this thesis research.

TABLE OF CONTENTS

Page

Abstract ...... 3

Dedication ...... 4

Acknowledgments ...... 5

List of Tables ...... 8

List of Figures ...... 9

Chapter 1: Introduction ...... 10

Chapter 2: Previous Work ...... 13

2.1 Introduction ...... 13

2.2 Geology of the Ohio Basement ...... 13

2.3 Geophysical Well Logs ...... 15

Chapter 3: Methods ...... 19

3.1 Well Logs ...... 19

3.2 Petrology ...... 19

3.3 Geochemistry ...... 22

Chapter 4: Results ...... 24

4.1 Petrographic Analysis ...... 24

4.2 X-Ray Fluorescence ...... 27

4.3 Well Log Response and Cuttings ...... 33

4.4 Statistical Analysis of Well Log Data ...... 36

Chapter 5: Discussion ...... 42 7

Conclusions ...... 52

References ...... 53

Appendix 1 ...... 57

Appendix 2 ...... 59

Appendix 3 ...... 62

Appendix 4 ...... 106

LIST OF TABLES

Page

Table 3.1: Table of Sidewall Core Samples ...... 21

Table 4.1: Point Counting Results ...... 25

Table 4.2: Bulk Geochemical Results ...... 28

Table 4.3: Supplemental Geochemical Classifications ...... 32

Table 4.4: Geophysical Well Log Tool Responses ...... 34

Table 4.5: Results of Mann-Whitney Test of Density Log Response ...... 41

Table 4.6: Results of Mann-Whitney Test of Gamma Log Response ...... 41

Table 4.7: Results of Mann-Whitney Test of PE Log Response ...... 41

LIST OF FIGURES

Page

Figure 1.1: Borehole Locations in Ohio ...... 11

Figure 2.1: Locations of Supplemental Well Data...... 14

Figure 4.1: Examples of Typical Thin Section Samples in this Study ...... 25

Figure 4.2: Samples Plotted onto QAP Diagram ...... 26

Figure 4.3: Iron Index Results ...... 29

Figure 4.4: Modified Alkali-Lime Index Results ...... 30

Figure 4.5: Aluminum Saturation Index Results ...... 31

Figure 4.6: Alkali Feldspar/K2O vs. Gamma Response ...... 38

Figure 4.7: Fe2O3 vs. Photoelectric Response ...... 39

Figure 4.8: Ferromagnesian Minerals vs. Photoelectric Response ...... 40

Figure 5.1: Felsic Bulk Density vs. Gamma Response ...... 46

Figure 5.2: Mafic Bulk Density vs. Gamma Response ...... 47

Figure 5.3: Mafic Photoelectric Response vs. Bulk Density Response ...... 48

Figure 5.4: Mafic Photoelectric Response vs. Gamma Response ...... 49

CHAPTER 1: INTRODUCTION

The bedrock geology of Ohio consists of Paleozoic strata that range in age from the Ordovician to the Permian (Baranoski, 2002). Below this cover are Precambrian units that have been sampled in a non-systematic manner by oil and gas wells and imaged in several seismic programs. Seismic studies have shown that Ohio is underlain by two large Precambrian assemblages, the Granite-Rhyolite province to the west and the

Grenville province in the central and eastern portion of the state. The former consists of unmetamorphosed granitic rocks, whereas the latter is composed of a complex assemblage of granitic and mafic rocks (Bass, 1960).

Two recently drilled wells located in east-central Ohio (Fig. 1.1) penetrated 610 feet (186 m) of crystalline basement in Noble county (Noble Olive A-1) and 90 feet (28 m) in Coshocton county (Cosh Mill Creek A-1). Sidewall cores from the Precambrian and a suite of geophysical well logs were collected by the well operator of both wells.

The data, which were made available for study by Eastern Mountain Fuel, allow a geochemical characterization of the basement to determine the rock types present that could then be used to compare to the well log data. The latter is of interest because the downhole tools were designed and calibrated to be used in sediments and it is not clear what the response of some of the tools will be in metamorphic and igneous rocks. A better understanding of the type and distribution of the different basement rocks in Ohio will improve the interpretation of seismic data and provide a better assessment of the nature of basement structures. 11

Figure 1.1. Locations of Cosh Mill Creek A-1 (MC A-1) and Noble Olive A-1 (O A-1) in Ohio.

The primary goals of this study were: (1) to characterize the mineralogy and composition of the Ohio basement rocks using the sidewall cores, and (2) to determine the best geophysical tools for identifying the rocks present.

The hypotheses tested are:

1. The core from both wells will have the same types of rock present.

Where it is exposed on the Canadian Shield the Grenville province is a complex assemblage of both mafic and felsic igneous and metamorphic rock types intercalated on a range of spatial scales (Montreuil and Constantin, 2010). The mineralogy and rock type of the core samples of this study were determined using standard petrographic classifications after data are collected by thin-section petrography and X-Ray fluorescence.

2. The geophysical well logs that are most responsive to changes in lithology in

sedimentary rocks (gamma-ray, bulk density, and photoelectric factor) can also

identify the similarities (or differences) in crystalline rock types.

The well logs used in the petroleum industry are designed and calibrated for use in sedimentary rocks. Nevertheless, rock properties such as natural radioactivity and bulk density can be measured in all rock types. Cross-plots of well log responses show differing clusters in sedimentary rocks and this grouping should also occur in crystalline rocks. Similarly, the photoelectric log, which is generally considered to be the best tool for determining lithology (Serra, 1984), should also be useful in differentiating between mafic and felsic rock types. The log signatures from the rock types determined using petrology and geochemistry were compared using non-parametric statistics to determine if the log signatures can discriminate rock types at a level of significance of at least 0.05.

CHAPTER 2: PREVIOUS WORK

2.1 Introduction

There is comparatively little detailed work on the well log responses of crystalline rocks in comparison to the studies done on sedimentary rocks. After a brief summary of the Precambrian geology in the subsurface of Ohio, a general overview is presented of the logging tools used in this study and the responses those tools record in sedimentary lithologies. Finally, there is a summary of the primary literature sources used for comparison to the data in this study.

2.2 Geology of the Ohio Basement

The two major basement provinces in Ohio are the Granite-Rhyolite province to the west and the Grenville province to the east (Figure 2.1; Baranoski, 2002; Harbi,

2005). The approximate depth-to-basement ranges from 2,500 feet (762 m) in western

Ohio to 13,000 feet (3,963 m) in eastern Ohio (Baranoski, 2002). The Granite-Rhyolite province consists of sedimentary and volcanic rocks of the East Continent Rift Basin, which is underlain by granitic igneous rocks (Baranoski, 2002). The Grenville province consists of intermediate to high-grade metamorphosed granitic rocks (Baranoski, 2002).

The lithologies within the Grenville province are mainly amphibolites and gneisses with scattered examples of schist/hornfels/marble, intermediate rocks, and granites (Figure

2.1).

Samples from wells located near the basement boundary in Fayette county (Fig. 2.1) were used to obtain geochronologic Rb-Sr analyses of feldspar and mica that yielded ages 14

Figure 2.1. Distribution of wells across the state of Ohio from which data was used. Lithologies (if available) are listed, and specific wells are labeled. The age dates from Fayette County are in the red circle with the tan infill, and other dated samples are in the black circle with the purple infill. The two wells used in this study are labeled O A-1 and MC A-1. The thick N-S line represents the boundary between the Granite-Rhyolite and Grenville Provinces (Bass, 1960; McCormick, 1961; Root, 1996; Harbi, 2005).

ranging from 898 ± 40 to 1242 ± 46 Ma, suggesting that the lithologies near this study area are of Grenville (1250-980 Ma) origin (Bass, 1960; Hofmann et al., 1972).

The previous data sets used to study the basement composition largely have been restricted to incomplete sidewall cores and drill cuttings (Bass, 1960; McCormick, 1961; 15

Root, 1996). These data were found to have limited vertical penetration of basement material. For example, the sample suites used by Bass (1960) and Hofman et al. (1972) represented less than a total of 61 m of penetration, which prevented the construction of detailed subsurface maps.

2.3 Geophysical Well Logs

Modern geophysical well logs are used by petroleum companies to identify rock and fluid types. The most common log types measure natural radioactivity, electrical conductivity or resistivity, sonic velocity, density, and neutron capture. The types of logs provided for this study are described below.

One of the most commonly deployed tools is the gamma ray, which measures the natural radioactivity of rocks. Rocks emit gamma rays as a result of the spontaneous disintegration of potassium, thorium, and uranium. Potassium is the most common, but lowest energy, of the three elements (Serra, 1984). In sediments an increase in gamma- ray response generally indicates an increase in shale content. However, sediments with a large number of feldspar grains, such as an arkose, also have high gamma-ray values.

The data are presented on the left track of a well log in American Petroleum Institute

(API) units that increase in magnitude to the right. The gamma ray tool has a vertical resolution of two feet, and records 75% signal within approximately one foot of the borehole sidewall.

The density tool emits gamma rays. The interaction of the gamma rays with the atoms in the host rock results in the production of secondary gamma rays that are measured by the tool. The variations in gamma ray response are indicative of bulk 16 electron density within the area of measurement (Rider, 2002). With a standard equation, which assumes that Z/A (electron density divided by atomic number) is equal to 0.5, electron density is converted to bulk density. The bulk density of the rock is presented on the right-hand track of a log in units of g/cm3 with the values increasing to the right.

Calibration of the log to a known lithology and fluid allows the conversion of the bulk density value to % porosity. Where porosity values are shown, the values vary from -

15% to +30% (limestone calibration) or from to 0% to 60% (sandstone calibration). In both cases the calculation of porosity can yield negative values if the host lithology has a greater bulk density than the lithology used for calibration. The tool attains 80% of data from within a 4-inch depth of the borehole and has a vertical resolution of 3 feet, however, high density lithologies, such as siderite nodules, can produce a response even in samples as small as a few inches (Beyer and Clutsom, 1978).

The photoelectric effect refers to the response of the host rock to low energy gamma rays produced by Compton scattering (Timur and Toksöz, 1985). The photoelectric response measured by the tool is a function of the mean atomic number of the target rock. Because this response is insensitive to porosity within the target rock, this tool is widely considered the best indicator of lithology. Tool response is presented on the right-hand track in units of barnes/electron with values increasing to the right, and has the same bed resolution/depth of penetration as the bulk density tool.

The neutron tool emits fast neutrons from a radioactive source (Rider, 2002). The neutrons lose energy as they collide with atoms in the borehole rock until they can be captured by an atom. That capture results in the emission of a gamma ray which is 17 measured by the tool. The capture of the neutrons is most efficient when the target atoms have the same mass. The result in that the tool is effectively a measure of the amount of hydrogen in the rock. Since hydrogen is most commonly present as water in the pore spaces the tool is a means to measure porosity. The tool is calibrated to the same lithology and fluid as the density tool and the % porosity is presented on the right-hand track with values increasing to the left. The neutron porosity tool gathers data within a

10-inch vertical window and penetrates 6-10 inches into a formation under typical logging speeds. Vertical resolution is slightly greater than 1 m (Rider, 2002).

Resistivity tools measure the response of the host rock to either an applied or induced current. The response of sedimentary rocks to this tool depends on lithology, porosity, pore geometry, and fluid type. The fluids in the subsurface vary from good conductors (brines) to good insulators (oil). The effect of the lithology is summed into a term known as the Formation Resistivity Factor (F). It has been experimentally shown that F varies as the inverse of porosity raised to a power between 2 and 2.15, but which is commonly assumed to be 2 (Lyons, 2010). The value of F can vary between 5 and 500.

The value is low for porous sandstones (10) and very high for low porosity limestones

(300-400). Therefore, the log response varies over several orders of magnitude and is displayed on the right-hand track using a log scale. Tool response is presented as ohm*m with values increasing to the right.

The depth of penetration in resistivity logs is proportional to the separation between electrodes and can vary from millimeters to several meters. Resistivity tools routinely sample at least two different depths. The reason is that the drilling process 18 results in invasion of the host rock by drilling fluid termed mud filtrate. The invasion closest to the borehole, which is termed the flushed zone, drives out all of the original formation fluid and most of any hydrocarbons that might have been present. Beyond the flushed zone is the invaded zone where formation fluids and mud filtrate mix. This invaded zone varies in thickness depending on parameters such as permeability and the rate of formation of mudcake on the borehole walls. Mudcake is the term applied to the buildup of solids from the mud on the borehole that occurs as the filtrate enters the formation. The depth of invasion is reduced by rapid mudcake buildup in regions of higher permeability in a formation. Comparison of log responses from all three zones provides information on depth of invasion, fluid type, and porosity (Serra, 1984).

CHAPTER 3: METHODS

3.1 Well Logs

Geophysical well logs available for the Noble Olive A-1 and Cosh Mill Creek A-

1 wells consisted of caliper, gamma-ray, neutron porosity, density porosity, bulk density, photoelectric potential, and resistivity. Those chosen for comparison were gamma-ray, bulk density, and photoelectric logs. The caliper and porosity tools were not considered to be diagnostic in crystalline rocks due to similar tool response amongst samples and tool calibration. Resistivity response was also considered unreliable, as fractures within the rock were found to significantly increase resistivity response (Löfgren, 2004).

Gamma-ray response was used as a proxy for the relative presence (or absence) of potassium feldspar, as significant variability of this mineral type was expected between boreholes. Both bulk density and photoelectric potential log response were used as a basis of comparison due to the increased tool response to heavier elements. Mafic lithologies should exhibit a higher bulk density/Pe response than common felsic mineral assemblages (Serra, 1984; Pechnig et al., 2005).

The well log response at depths from which the petrologic samples were taken were compared using the Mann-Whitney test and a 0.05 level of significance to determine if the differences in well log response between the lithologies was significant.

This nonparametric statistical test was used because of the low sample numbers.

3.2 Petrology

Core samples from two different borehole sidewalls (Table 3.1) were obtained for analysis in this study. Sidewall cores are circular samples retrieved in situ from the 20 borehole wall. The core samples were thoroughly washed using hot tap water and a brush in order to remove any drilling mud or debris on the surface. Once clean, the samples were dried and lithologic descriptions of each core section were made using a 10x hand lens in order to determine which samples to thin section. It should be noted that whole sidewall cores were unable to be collected for samples: O-10333, O-10426, MC-7332, and MC-7347.

Thirteen crystalline basement sidewall cores were chosen to be made into thin sections by Applied Petrographic Services, Inc.. The cores were cut vertically into approximately 0.64 cm-wide pieces using an Isomet 11-1180 low speed saw. The Isomet saw was used in order to insure minimal sample loss, due to the small size of the sample suite. The sample billets were then sent to Applied Petrographic Services, Inc. for thin sectioning. Once returned to Ohio University, thin sections were observed using a petrographic microscope with plane-polarized light (PPL) and cross-polarized light

(XPL).

Minerals were identified under PPL and XPL using 10x magnification, and a

Bernoulli sampling process (grid distance > grain size; adjacent grains independent; x =

0.5 mm/ y = 1 mm), and optical properties such as pleochroism, relief, extinction characteristics, birefringence, twinning, and interference figures (Neilson and Brockman,

1977) were noted. After the minerals were identified and point counts of 800 points were recorded, the mineral data were normalized and plotted onto a Quartz-Alkali Feldspar-

Plagioclase (QAP) ternary diagram.

Table 3.1. Sidewall core samples from the two wells in this study. Samples beginning with O = Noble Olive, those beginning with MC = Cosh Mill Creek.

Sample Name Total Depth (ft) Hand Sample Description O-10094 10094 Quartz, Pyroxene/Hornblende

O-10165 10165 Quartz, Pyroxene/Hornblende

O-10190 10190 Quartz, Pyroxene/Hornblende, Feldspar

O-10234 10234 Quartz, Pyroxene/Hornblende, Feldspar

O-10243 10243 Quartz, Pyroxene/Hornblende

O-10251 10251 Quartz, Pyroxene/Hornblende

*O-10333 10333 Quartz, Pyroxene/Hornblende, euhedral mafics

O-10356 10356 Quartz, Feldspar, Pyroxene/Hornblende, red oxide

O-10385 10385 Quartz, Feldspar, Pyroxene/Hornblende

*O-10426 10426 Quartz

O-10459 10459 Quartz, Feldspar, Pyroxene/Hornblende

MC-7286 7286 Pyroxene/Hornblende, Quartz

MC-7300 7300 Pyroxene/Hornblende, Quartz, Feldspar

MC-7313 7313 Quartz, Pyroxene/Hornblende

*MC-7332 7332 Pyroxene/Hornblende, Quartz

*MC-7347 7347 Quartz, Pyroxene/Hornblende *No thin section made, insufficient sample material.

3.3 Geochemistry

Bulk rock composition was determined using the Rigaku Supermini 200

Wavelength Dispersive X-Ray Fluorescence (XRF) spectrometer at Ohio University. In order to perform X-Ray Fluorescence Spectrometry (XRF) analyses, all 16 basement sidewall core sections were first wrapped in paper to prevent metal contamination during crushing. Then, the sections were broken into pea-sized pieces on a metal plate using a clean rock hammer. Pieces were then crushed into powder using an Angstrom TE250 ring pulverizer and tungsten carbide mill. Glass beads were prepared for XRF analyses from powders using a 7:1 dilution (7 parts Li-borate flux to 1-part sample powder (Table

3.2), and the XRF Scientific Fusion Phoenix machine located at Ohio University. The

7:1 dilution method allows more accurate determination of selected trace elements (V,

Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Ce) as well as analysis of major element oxides (Kansai,

2008).

The weight percentage of major element oxides (SiO2, TiO2, Al2O3, Fe2O3, MgO,

CaO, Na2O, K2O, and P2O5), along with the trace elements (ppm) were measured. X-ray intensities were converted to concentrations using the Fundamental Parameters method and calibrated against 12 standards (AGV-2, BCR-2, BHVO-2, BIR-1a, DNC-1a, DTS-

2b, GSP-2, QLO-1, RGM-2, SDC-1, STM-2, and W-2a) obtained from the United States

Geological Survey (Sprang, 2000). The element concentrations of the standards are shown in Appendix 1. A qualitative scan of 0.18 – 6 angstroms (Å) was also carried out to evaluate whether any other elements not measured during the routine analytical setup were present above the 10 ppm detection limit, however none were present. The results 23 were then used to compare samples between the wells in this study. After point counting and bulk geochemical data were collected, both were compared to geophysical well log response.

CHAPTER 4: RESULTS

4.1 Petrographic Analysis

Thin section observations of samples from the Noble Olive A-1 and Cosh Mill

Creek A-1 wells showed distinct differences between the boreholes (Table 4.1, Appendix

4). It should be noted that the alteration minerals reported in Table 4.1 consist of titanite, opaques, tourmaline, apatite, zircon, and accessory minerals. All the samples were phaneritic with crystal sizes of 1-30 mm. Samples from both boreholes exhibit a similar subhedral, seriate, phaneritic texture (Figure 4.1), with a more prominent foliation of mafic minerals in the Cosh Mill Creek A-1 well. The point counts of thin sections showed that the largest variations between boreholes were the increased amount of quartz

(mean = 25.77%) and alkali feldspar (mean = 47.64%) in the Noble Olive A-1 sections and the greater modal percentages of biotite (mean = 1.96%), plagioclase feldspar (mean

= 68.06%), and hornblende (mean = 8.6%) in the Cosh Mill Creek A-1 sections (Table

4.1).

The modal data were plotted on a Q-A-P (no feldspathoids present) ternary diagram for plutonic felsic rocks using normalized quartz, alkali feldspar, and plagioclase values (Le Bas and Streckeisen, 1991; Figure 4.2). Six of the Noble Olive A-1 samples plot in the syenogranite field, two in the monzogranite field, and one in the quartz syenite field. In contrast, the Cosh Mill Creek A-1 samples plot in the diorite, quartz diorite, and tonalite fields (Figure 4.2).

Table 4.1 Modal mineralogy of basement samples from thin section point counts. Samples beginning with O = Noble Olive, and MC = Cosh Mill Creek. Q = quartz, Pl = plagioclase, K-Fl = alkali feldspar, M = muscovite, B = biotite, Hbl = hornblende, Opx = orthopyroxene, Cpx = clinopyroxene, and At = alteration.

Sample Q Pl K-Fl M B Hbl Opx Cpx At Name MC-7286 2.4 77.2 1.6 0.0 2.9 5.2 0.8 2.8 6.6 MC-7300 10.5 66.3 0.6 0.0 1.3 17.7 0.0 0.0 3.3 MC-7313 26.2 60.7 3.1 0.0 1.7 2.9 0.0 0.0 4.9 O-10094 21.4 31.5 40.2 0.0 0.0 0.0 0.0 0.0 6.9 O-10165 28.0 19.1 48.1 0.0 1.6 1.0 0.0 0.0 2.2 O-10190 25.3 26.2 48.0 0.0 0.0 0.0 0.0 0.0 0.3 O-10234 28.1 14.6 51.0 0.0 0.2 1.9 0.0 0.0 3.4 O-10243 30.1 14.2 44.7 0.0 0.0 6.3 0.0 0.0 4.4 O-10251 27.5 20.6 48.6 0.0 1.9 0.0 0.0 0.0 1.1 O-10356 30.3 18.2 45.1 0.0 0.0 2.2 0.0 0.0 3.9 O-10385 23.4 24.0 46.4 0.0 0.0 3.0 0.0 0.0 2.8 O-10459 17.8 17.8 56.7 0.0 0.3 5.0 0.0 0.0 2.0 25

5 mm

Figure 4.1. Scans of thin sections from a typical sample in each well under crossed polarized light. Both show a similar subhedral seriate porphyritic texture across. Compositional banding, shown here, is more prevalent in MC-7300 compared to O- 10165. 26

Figure 4.2. QAP ternary diagram showing all the normalized mineral modal data obtained from thin section point counting of the Noble Olive A-1 (red circles) and Cosh Mill Creek A-1 (green circles). The separation of the data indicate two separate parent rocks (Streckeisen, 1974).

4.2 X-Ray Fluorescence

Bulk geochemical results are reported in Table 4.2 as weight-percent and parts per million (ppm) for major and trace elements, respectively. The Fundamental Parameters method inherently validates results and produces an accuracy within the 99th percentile

(De Boer et al., 1993). Due to this inherent validation, results are not reported with 1σ error. The geochemical classification of the samples was carried out using the classification scheme of Frost and Frost (2008).

The type of intrusive or volcanic rock present was determined by first calculating the Fe-Index, which was then supplemented by the Modified Alkali-Lime Index (MALI), and the Aluminum Saturation Index (ASI). The Fe-Index is determined using

FeO/(FeO+MgO) values and the results are classified as Ferron or Magnesian. Six of 10 samples in the Noble Olive A-1 well fell into the magnesian category with the four remaining samples plotting in the ferroan field (Figure 4.3). Analysis of the Cosh Mill

Creek A-1 samples resulted in all but one sample (MC-7300) plotting in the magnesian field of the Fe-index.

The Modified Alkali-Lime Index (MALI) was then used to separate rocks into alkalic, alkali-calcic, calc-alkali and calcic suites by plotting Na2O+K2O-CaO against weight-percent Si (Frost and Frost, 2008). The Cosh Mill Creek A-1 data plot in the alkali-calcic to calc-alkalic fields, whereas the Noble Olive A-1 data vary from alkalic to calc-alkalic (Figure 4.4).

Table 4.2 Major and trace element rock XRF geochemistry results from the two wells. Values of major elements expressed as oxides are in wt%, whereas trace elements are in ppm. b.d. = below detection. Note sample O-10426 was described as quartz in hand sample.

SiO2 TiO2 Al2O3 Fe2O3 MgO MnO CaO Na2O K2O P2O5 Ba Ce Rb Sr Y Zr Sample #

O-10094 69.42 0.21 13.04 3.18 0.21 0.02 0.58 4.49 4.47 0.09 424 129 104 34 23 285 O-10165 72.74 0.27 13.49 2.06 0.48 0.06 0.60 4.98 4.36 0.05 16 155 54 14 24 425 O-10190 76.11 0.08 11.56 0.26 0.12 0.02 0.30 3.82 4.51 0.04 350 146 83 27 b.d. 67 O-10234 72.80 0.43 11.52 4.21 0.42 0.08 0.85 3.07 5.19 0.08 288 146 101 32 72 656 O-10243 72.17 0.46 11.80 3.80 0.60 0.07 1.33 4.07 4.28 0.08 237 223 74 45 85 644 O-10251 71.64 0.29 14.42 1.93 0.39 0.02 0.33 4.68 5.36 0.05 293 162 69 18 22 480 O-10333 75.91 0.15 13.56 0.96 0.20 0.02 0.74 6.88 1.07 0.06 97 124 24 60 45 146 O-10356 62.47 0.44 17.70 4.46 2.00 0.06 5.41 5.67 0.67 0.19 309 181 b.d. 765 b.d. 85 O-10385 71.67 0.23 13.75 2.18 0.21 0.03 1.14 4.92 4.48 0.06 204 220 85 69 94 100 O-10426 97.49 0.06 0.76 0.04 0.01 0.01 0.06 0.07 0.38 0.04 b.d. 218 17 b.d. b.d. 42 O-10459 70.08 0.46 13.98 2.53 0.07 0.05 1.19 3.53 7.11 0.07 651 185 130 22 102 727

MC-7286 56.15 0.82 18.59 7.52 3.40 0.09 5.65 5.82 0.83 0.31 235 173 4 648 15 128 MC-7300 73.78 0.44 12.22 3.58 0.34 0.05 1.47 5.26 2.32 0.08 231 203 48 44 103 609 MC-7313 65.19 0.42 16.92 3.91 1.60 0.05 4.43 5.43 0.84 0.16 371 144 3 661 b.d. 92 MC-7332 59.33 0.61 17.91 5.61 2.79 0.09 5.97 5.44 1.09 0.24 183 151 6 735 b.d. 110 MC-7347 56.79 0.73 18.08 6.16 4.21 0.07 4.75 5.12 1.31 0.27 170 111 19 648 b.d. 134

1.1 Fe-Index

1.0

) weight % 0.9 total Ferroan rocks 0.8

0.7 /(MgO + FeO /(MgO total 0.6 Magnesian rocks Cosh Mill Creek A1 FeO Noble Olive A1 0.5 45 50 55 60 65 70 75 80 SiO2 weight % Figure 4.3. Plot showing the results of the Fe-Index vs SiO2 calculated for both wells. The samples being predominately magnesian also show a distinct bimodal distribution between wells, as well as a similarity to the transitional convergent-margin magma signatures of Frost and Frost (2008). Values of FeOtotal were determined using [Fe2O3]*0.8998.

Modified Alkali-Lime Index 12

4 CaO weight % CaO weight

- 2 O 2 0 O + K O 2

Na -2

-4

-6 Cosh Mill Creek A1 Noble Olive A1 -8 45 50 55 60 65 70 75 80

SiO2 weight % Figure 4.4. Modified Alkali-Lime Index (MALI) plot showing the results of both Noble Olive A-1 and Cosh Mill Creek A-1. A noticeable bimodal distribution suggests a significant difference in lithology between boreholes. Two samples from Cosh Mill Creek exhibit greater silica content and one sample from Noble Olive has a lower silica content than the rest of the samples in the respective groups (Frost and Frost, 2008).

The Aluminum Saturation Index (ASI) was calculated using the formula Al/(Ca-

1.67P+Na+K). A plot of ASI versus SiO2 (Figure 4.5) can determine if the rocks are peraluminous (ASI > 1.0), metaluminous (ASI<1.0 but molecular Na+Kmolecular Al). The Noble Olive A-1 samples have ASI values ranging from 0.865-1.306 (sample O-10426), and Cosh Mill

Creek A-1 samples showed similar ASI values of 0.866-0.996 except for sample O-

10426, which was not used (see Table 4.3). Using all three indices, the samples in the

Noble Olive A-1 plot as syenogranite, whereas the Cosh Mill Creek A-1 well samples are tonalite/dioritic gneiss (Frost and Frost, 2008) (Table 4.3).

Aluminum Saturation Index 2

Peraluminous

1 1.67*P)+Na+K)molar - Metaluminous Al/((Ca Noble Olive A-1 Cosh Mill Creek A-1 0 45 55 65 75

SiO2 Weight %

Figure 4.5. Bivariate plot of ASI vs. SiO2. Samples from Noble Olive and Cosh Mill were predominately metaluminous, or aluminum deficient and silica saturated. O-10251 was the only peraluminous sample (Frost and Frost, 2008). 32

Table 4.3 Aluminum Saturation Index, Iron Index, and Modified Alkali-Lime Index results. Samples beginning with O = Noble Olive, those beginning with MC = Cosh Creek. Samples labeled N/a could not be used due to mineralogy/geochemistry (O-10426), and/or the lack of thin sections.

Sample ASI Fe-Index MALI Lithology O-10094 0.990 0.930 Alkalic Monzogranite

O-10165 0.968 0.793 Alkalic Syenogranite

O-10190 0.990 0.662 Alkali-Calcic Syenogranite

O-10234 0.951 0.899 Alkali-Calcic Syenogranite

O-10243 0.865 0.850 Alkali-Calcic Syenogranite

O-10251 1.028 0.816 Alkalic Syenogranite

O-10333 0.986 0.813 Calc-Alkalic Syenogranite

O-10356 0.900 0.668 Calc-Alkalic Syenogranite

O-10385 0.919 0.905 Alkali-Calcic Syenogranite

O-10426 1.306 0.787 N/a N/a

O-10459 0.897 0.765 Alkalic Syenogranite

MC-7286 0.912 0.665 Alkali-Calcic Diorite

MC-7300 0.890 0.905 Calc-Alkalic Quartz Diorite

MC-7313 0.956 0.688 Calcic Tonalite

MC-7332 0.866 0.644 Calc-Alkalic N/a

MC-7347 0.996 0.568 Alkali-Calcic N/a

4.3 Well Log Response and Cuttings

Comparison of geophysical well log responses in both wells showed unexpected variations. The lithological variation should be most noticeable in the gamma-ray, density, and photoelectric logs. Variations in resistivity are also related to rock properties, but mainly as a function of the geometry of the pore connections (e.g., Rider,

2002). The resistivity tool is also affected by the amount of porosity and the type of fluid filling the pores. The neutron tool is primarily a function of the presence of water in the rock.

The gamma-ray tool response at the depths from which the samples were collected varied from 110 to > 400 American Petroleum Institute (API) units in the Noble

Olive A-1 well and from 30-48 API units (ave.43±7) in the Cosh Mill Creek A-1 well

(Table 4.4). Variability within the data from the Noble Olive well shows what will be considered three separate groups. Group 1 contains two samples which exceed 400 API,

Group 2 contains samples with gamma responses from 150 - < 400 API, and Group 3 is comprised of samples with responses < 150 API. Units from Group 1 and Group 2 likely contained some amount of higher energy thorium or uranium, and gamma responses from

Group 3 shows an expected response if only potassium was present. Due to the average gamma response of Group 3 (122 API), the data suggest a higher percentage of potassium in the Noble Olive A-1 well.

The bulk density responses at the sample depth intervals in the Olive A-1 well varied from 2.57 - 2.70 g/cm3, with the exception of the reading opposite sample O-

10234, which is much lower (Table 4.4). The increase in hole width registered by the 34 caliper tool opposite sample O-10234 and the shallow depth of penetration of the density tool mean that this value is invalid and was not considered in further analyses. The bulk density values in the Mill Creek well vary from 2.75 - 2.80 g/cm3. The photoelectric potential values at the sampled depth intervals varied from 1.85 - 3.20 barnes/electron in the Noble Olive well and 3.00 to 3.90 in the Mill Creek well (Table 4.4). The PE value opposite

Table 4.4 Geophysical Well Log Responses for Noble Olive and Cosh Mill Creek Well Samples. Samples beginning with O = Noble Olive, those beginning with MC = Cosh Creek. Bit diameter was 7.88 inches in both holes. No reading = n.r.

Sample Gamma Caliper Density PE Neutron Resistivity (API) (inches) gm/cc (barnes/ (% (ohm-m) electron) porosity) O-10094 >400 8.20 2.60 2.10 -1.00 4,000 O-10165 115 8.00 2.60 2.90 -1.00 >100,000 O-10190 110 8.10 2.70 2.50 -1.00 >100,000 O-10234 120 9.20 2.09 3.20 4.50 190 O-10243 395 8.30 2.64 3.00 -1.00 12,000 O-10251 382 8.30 2.60 2.00 -1.00 6,000 O-10333 135 8.20 2.65 3.10 -1.00 80,000 O-10356 130 8.20 2.65 3.20 -1.00 60,000 O-10385 >400 8.40 2.57 2.90 0.20 9,000 O-10426 355 9.10 2.55 1.85 -1.90 90,000 O-10459 262 8.50 2.60 3.10 -1.00 >100,000 MC-7286 30 8.50 2.75 3.00 0.50 40,000 MC-7300 42 8.75 2.80 3.90 1.00 30,000 MC-7313 45 8.20 2.75 3.00 1.00 6,000 MC-7332 48 8.10 2.80 4.50 2.00 35,000 MC-7347 42 7.50 n.r. n.r. n.r. ~10,500 35 sample O-10234 was also removed from further analysis because of the impact of hole rugosity on the caliper tool response.

The neutron porosity measurements in both wells were low. The range in the

Olive A-1 well was -1.0 to 0.2 porosity units (pu) with one exception. The negative neutron porosity values were unexpected. The tool was calibrated to limestone and the negative responses found in Noble Olive A-1 suggest the material contains less hydrogen than a dry (i.e., 0% porosity) matrix. The negative values, therefore, indicate that the tool is miscalibrated for the lithologies present in the Olive well and the values cannot be used for evaluation. The neutron readings in the Mill Creek A-1 range from 0.5-2 pu. The consistently low neutron porosity values within both wells indicates very low hydrogen concentration in pores or bound within crystals.

The resistivity tool provides several curves with different depths of penetration and vertical resolution depending on the sensor separation. The MLR1C resistivity measurements have the closest electrode spacing and therefore the shallowest penetration and greatest vertical resolution, which means the values are most like the sampled core locations. The resistivity values for the MLR1C log in the Noble Olive well ranged from

190->100,000 Ωm (excluding value opposite sample O-10234, which was also affected by borehole rugosity). The Cosh Mill Creek responses ranged from 6,000-40,000 Ω-m.

The accuracy of the higher responses is problematic (Löfgren, 2004).

4.4 Statistical Analysis of Well Log Data

Statistical tests were applied to the different data sets to determine if: (1) the data from the two wells could be shown to be significantly different, and (2) to see if the well log responses can differentiate the rock types found. The null hypothesis (Ho) is that the two samples are from the same population. Statistical analyses of the bulk density, gamma-ray, and PE responses are shown in Appendix 2. Significance results are then reported in Tables 4.5, 4.6, and 4.7 for bulk density, gamma, and PE, respectively.

Results from the statistical analyses show that the null hypothesis was rejected for the density tool at a 1-tail significance of 0.025 and 0.05 (Table 4.5). Geophysical well log response of the gamma tool were found to reject the null hypothesis at all levels of comparison (Table 4.6), and well log response of the photoelectric log were found to be unable to reject the null hypothesis (Table 4.7). The rejection of the null hypothesis indicates a unique relationship between the data, and shows which tools are able to accurately delineate lithology.

Bivariate plots of well log responses to certain minerals and elements were constructed to determine if those minerals had an effect on log response. The gamma-ray values in both wells were compared to K-feldspar modal percent and wt% K2O (Figure

4.6). The Pe log values were plotted vs. Fe2O3 wt% (Figure 4.7) and total Ferromag mineral (hornblende+biotite+pyroxenes+opaques) (Figure 4.8) content since Fe is known to strongly influence Pe response (Serra, 1984).

Results from a comparison between K-feldspar/K2O and Gamma tool response show segregation between the Cosh Mill Creek and Noble Olive wells. However, six 37 samples showed similar values in relative weight-percent K2O and a gamma response range of 30-355 API, showing weight-percent K2O was unable to explain the spread of values. Figures 4.7 and 4.8 also show similar PE response in six samples, and the inability to explain the spread of values with respect to ferromagnesian minerals/weight- percent Fe2O3 and photoelectric tool response.

Alkali Feldspar vs. Gamma Response 60.0

50.0

40.0

30.0

20.0

Alkali Feldspar %)(Modal Feldspar Alkali 10.0 Cosh Mill Creek Noble Olive Group 1 Noble Olive Group 2 Noble Olive Group 3 0.0 0 100 200 300 400 500 Gamma Response (API) K O vs. Gamma Response 8.0 2 Cosh Mill Creek Noble Olive Group 1 7.0 Noble Olive Group 2 Noble Olive Group 3 6.0

5.0

4.0

O (Weight %) O (Weight 3.0 2

K 2.0

1.0

0.0 0 100 200 300 400 500 Gamma Response (API) Figure 4.6. Bivariate plots of modal-percent alkali feldspar (top) and weight-percent potassium oxide (bottom) plotted against gamma tool response. Segregation of data suggests the gamma tool is capable of delineating lithologies due to relative potassium and the presence of alkali feldspar (Pechnig et al., 2005). 39

Iron Oxide vs. PE Response 5.0 Cosh Mill Creek 4.5 Noble Olive Group 1 Noble Olive Group 2 4.0 Noble Olive Group 3

3.5

3.0

PE PE (Barnes/Electron) 2.5

2.0

1.5 0 2 4 6 8 Fe2O3 (Weight %) Figure 4.7. Bivariate plot of Fe2O3 weight-percent vs. photoelectric response in both wells. Iron content can significantly influence Pe response (Serra, 1984) no significant relationship exists between log response and iron oxide content. Overlap in Pe response suggests that this tool may be ineffective in delineation of lithologies between wells. 40

Ferromagnesian Minerals vs. PE Response 4.50

4.00

3.50

3.00

2.50

PE PE (Barnes/Electron) Cosh Mill Creek Noble Olive Group 1 2.00 Noble Olive Group 2 Noble Olive Group 3 1.50 0.0 5.0 10.0 15.0 20.0 25.0 Ferromagnesian Minerals (Modal %) Figure 4.8. Bivariate plot of modal-percent ferromagnesian minerals vs. photoelectric response in both wells. Iron content can significantly influence Pe response (Serra, 1984), and no significant relationship exists between log response and iron oxide content. Overlap in Pe response suggests that this tool may be ineffective in delineation of lithologies between wells. 41

Table 4.5

Significance of Mann-Whitney Statistical Analysis for Density Response

1-Tail 2-Tail Ucrit Result

0.001 0.002 0 Accept Ho

0.01 0.02 3 Accept Ho

0.025 0.05 5 Reject Ho

0.05 0.1 7 Reject Ho

Table 4.6

Significance of Mann-Whitney Statistical Analysis for Gamma Response

1-Tail 2-Tail Ucrit Result

0.001 0.002 2 Reject Ho

0.01 0.02 7 Reject Ho

0.025 0.05 9 Reject Ho

0.05 0.1 12 Reject Ho

Table 4.7

Significance of Mann-Whitney Statistical Analysis for PE Response

1-Tail 2-Tail Ucrit Result

0.001 0.002 0 Accept Ho

0.01 0.02 3 Accept Ho

0.025 0.05 5 Accept Ho

0.05 0.1 7 Accept Ho

CHAPTER 5: DISCUSSION

Mineralogical and bulk geochemical analysis of sidewall core samples from

Noble Olive A-1 and Cosh Mill Creek A-1 has allowed for the classification of lithology at depth. Samples from Noble Olive A-1 were found to be predominately ferroan and magnesian syenogranite. Sidewall core samples from Cosh Mill Creek A-1 were found to be magnesian diorite, quartz diorite, and tonalite (with increasing depth). Based on previous research of the Ohio basement by Bass (1960), McCorkmick (1961), Gonterman

(1973) and Baranoski (2002), variability between boreholes was expected to be minimal considering the sample locations.

Bass (1960) and Gonterman (1973) identified several different lithologies at depth within the Grenville province of Ohio: mid-to-high grade amphibolites and gneisses.

Geochemical and point counting analysis of samples from Noble Olive A-1 substantiate these findings within the Ullman well by Gonterman (1973) with the presence of potassium feldspar, plagioclase feldspar, quartz, hornblende, and biotite. These findings also agree with Figure 4.2, and the geochemical results of samples retrieved from Noble

Olive A-1. Analysis of samples recovered from Cosh Mill Creek A-1 also support the findings of Gonterman (1973) within the Lee well with plagioclase comprising the majority of the mineral mode, and the presence of potassium feldspar, quartz, alteration minerals, and other mafic minerals. Gamma ray tool response in both Noble Olive (aside from zones > 400 API) and Cosh Mill Creek is also consistent with the mineralogy of the

Ullman and Lee wells (Gonterman, 1973), with a greater tool response present in the

Noble Olive well compared to the response in Cosh Mill Creek. 43

Bartetzko et al. (2005) aimed to constrain geophysical well log response of mafic igneous and metamorphic rocks, and Pechnig et al. (2005) studied the effect on well log response due to compositional variation in felsic rocks. Basalt, gabbro, resedimented volcaniclastics, and metamorphosed continental basement were analyzed over 19 different boreholes to determine mafic well log response (Bartetzko et al., 2005). Felsic samples consisted of: biotite granite, monzonite, syenite, aplite, sillimanite-bearing biotite-paragneiss, hornblende gneiss, acid-to-mafic orthogneisses, and biotite-paragneiss

(Pechnig et al., 2005).

Bartetzko et al. (2005) found that physical properties related to compositional variability (e.g., gamma ray response), plotted against physical properties associated with structural variability (e.g., density) show the ability to delineate lithologies from varying geologic provinces. Pechnig et al. (2005) also found gamma ray response to most accurately predict lithology, considering alkali-feldspar prevalence in felsic rock. The lower oceanic crust and continental crust mafic samples (composed of gabbro and highly metamorphosed continental crust) have the same general density (2,800 – 3,000 kg/m3) but vary over 4 orders of magnitude in resistivity, due to the structure and textural characteristics of the rock, as shown in Figure 6a of Bartetzko et al. (2005). It should be noted that gamma response from oceanic and continental crust fall into separate fields, as shown in Figure 8a of Bartetzko et al. (2005). This segregation is due to a mineralogical variability (presence of alkali feldspar) between the two lithologies.

Furthermore, continental mafic rocks exhibit a low range mean PE response (3.6 -

4.7). However, this is derived from between 84 and 1316 samples from two boreholes. 44

The total range of all mafic rocks was found to vary between 3 and ~ 6.5 (based on as few as 13 and as many as 1580 samples per borehole in each rock type), as shown in

Figure 5/Appendix 3 of Bartetzko et al. (2005).

Pechnig et al. (2005) relied on a different criterion in order to delineate lithologies. Gamma and density response were both used in conjunction with potassium

(K2O) concentration in an attempt to delineate between felsic lithologies. Both Table 5 and Figure 4 in Pechnig et al. (2005) show a gamma log response greater (76 – 333 API) than the mafic responses from Bartetzko et al. (2005). Both Bartetzko et al. (2005) and

Pechnig et al. (2005) show the most useful lithologic predictors to be density, total gamma ray, and photoelectric (Pe) response, with resistivity measurements exhibiting a minor influence (texture). It should be noted that Pechnig et al. (2005) include a basis for delineation between paragneiss, orthogneiss, and igneous rock, which is beyond the scope of this study. Further, comparisons of all minerals/element oxides and each tool response is shown in Appendix 3. These were not considered due to the comparisons to previous research and lack of applicability.

Overall sample size associated with this study is notably smaller compared to that of Bartetzko et al. (2005) and Pechnig et al. (2005). However, considering borehole proximity, relative depth, and previous mapping of the granite-rhyolite/Grenville boundary, the magnitude of lithologic and mineralogical variability between boreholes was unexpected. Post-Grenville extension of the basement rock in the study area could allow for such variability. Similarities in crystal size and the presence of a similar subhedral seriate phaneritic texture were also unexpected. Textural similarities of 45 samples in this study are likely due to regional tectonism or the related pressure/temperature fluctuations throughout geologic time (Spry, 1969).

In order to compare felsic samples of Noble Olive to results from Pechnig et al.

(2005), mean values of plutonic, orthogneissic, and paragneissic gamma/bulk density responses from Pechnig et al. (2005) were plotted as fields on a bivariate plot. Mean gamma/bulk density response of the three groups from the Noble Olive well were then plotted. Figure 5.1 shows Group 1 plotting outside of any fields, Group 2 within the plutonic field, and Group 3 within the para/orthogneiss fields as defined by Pechnig et al.

(2005).

Bulk Density vs. Gamma Response

2.9 ) 3

2.8 g/cm

2.7

2.6

Noble Olive Group 1 2.5 Noble Olive Group 2 Noble Olive Group 3 Bulk Density Response ( Response BulkDensity Pechnig Plutonic Pechnig Orthogneiss Pechnig Paragneiss 2.4 50 100 150 200 250 300 350 400 Gamma Response (API) Figure 5.1. Bivariate cross plot of mean/standard deviation bulk density and gamma geophysical tool responses from plutonic (yellow), orthogneiss (purple), and paragneiss (blue) samples from Pechnig et al (2005). Also plotted are the mean and standard deviation of samples from Noble Olive (red). Fields for each Pechnig data set are plotted based on the furthest extent of each sample set.

Bartetzko et al. (2005) compared bulk density, gamma, and photoelectric responses of mafic lithologies. Mean and standard deviation of tool responses at sampled intervals were calculated, then plotted following the same approach used with data from

Pechnig et al. (2005). Figure 5.2 shows the plotted gamma and bulk density responses of basalt and amphibolite. Samples from Cosh Mill exhibit a bulk density response similar to that of basalt, yet show higher gamma responses than both basalt and amphibolite.

Bartetzko et al. (2005) attributed higher gamma responses to enrichment of radioactive 47 elements during metamorphism. However, the higher gamma response in Cosh Mill

Creek is likely due to the relative high K2O concentration (Table 4.2).

Bulk Density vs. Gamma 3.2

3 ) 3 2.8

2.6

2.4

2.2 Bulk Density Response (g/cm Response BulkDensity Cosh Mill Creek Bartetzko Basalt Bartetzko Amphibolite 2 0 10 20 30 40 50 Gamma Response (API) Figure 5.2. Bivariate cross plot of bulk density vs. gamma tool response of basalt and amphibolite samples from Bartetzko et al (2005), and Cosh Mill Creek samples. Mean and standard deviations for each sample set were used. Note that a basalt field is absent due to spread of the sample set.

Figure 5.3 shows photoelectric response plotted against bulk density response.

Mann-Whitney analysis showed PE was unable to significantly delineate lithology, which is also shown in Figure 5.3. Cosh Mill Creek samples show a lower PE and density response when compared to the amphibolite samples from Bartetzko et al. (2005). This 48 lower response of both tools is attributed to lower Fe2O3 concentrations within samples from the Cosh Mill Creek well. Amphibolites showed a mean Fe2O3 concentration of 8.3 weight-percent, with a mean Fe2O3 concentration of 5.3 weight-percent in samples from

Cosh Mill Creek.

PE vs. Bulk Density

Cosh Mill Creek 6 Bartetzko Basalt Bartetzko Amphibolite

3 PE (barnes/electron) PE Response

2 1.8 2.2 2.6 3 Bulk Density Response (g/cm3) Figure 5.3. Bivariate cross plot of bulk density vs. photoelectric potential tool response of basalt (green) and amphibolite (gray) samples from Bartetzko et al (2005), and Cosh Mill Creek samples (yellow). Mean and standard deviations for each sample set were used. Note that a basalt field is absent due to spread of the sample set.

PE vs. Gamma 6.5

5.5

4.5

3.5

PE (barnes/electron) PE Response 3 Cosh Mill Creek 2.5 Bartetzko Basalt Bartetzko Amphibolite 2 0 5 10 15 20 25 30 35 40 45 Gamma Response (API) Figure 5.4. Bivariate cross plot of photoelectric potential vs. gamma tool response of basalt (green) and amphibolite (gray) samples from Bartetzko et al (2005), and Cosh Mill Creek (yellow) samples. Mean and standard deviations for each sample set were used. Note that a basalt field is absent due to spread of the sample set.

Figure 5.4 shows the cross plot of gamma response vs. photoelectric potential tool response of basalt and amphibolite samples from Bartetzko et al. (2005), as well as gamma/PE response of samples from Cosh Mill Creek. Samples from this study exhibit a higher gamma response overall, which again is attributed to the higher concentration of

K2O. Photoelectric response is lower than that of the amphibolites, as is also seen in

Figure 5.3, which may be due to the lower concentration of Fe2O3 in Cosh Mill Creek compared to that of the amphibolites from Bartetzko et al. (2005). Both of these chemical variations have caused the samples from Cosh Mill Creek to plot away from samples 50 from Bartetzko et al. (2005), showing that lithologies from Cosh Mill Creek are different than those published by Bartetzko et al. (2005).

Bulk geochemical analysis in this study was found to follow trends and results of

Frost and Frost (2008). Modified Alkali Lime Index (MALI) values increase with respect to total weight-percent silica and alkali feldspar volume (Figure 4.4). Bulk geochemical trends in Cosh Mill Creek A-1 were also found to support QAP trends with respect to depth, and may potentially be an artifact of fractional crystallization, as shown in Figure

4.2 (Frost and Frost, 2008). Furthermore, the relative areas in which samples from Noble

Olive A-1 and Cosh Mill Creek A-1 plot on the MALI are similar to areas defined by

Frost et al. (2001) in which specific lithologies were proposed to plot. Both Noble Olive

A-1 and Cosh Mill Creek A-1 followed expected trends with respect to the MALI.

Samples which were found to have a greater amount of quartz showed a lateral trend on the MALI and no increase in Na2O+K2O-CaO values, as feldspar/quartz content has been shown to be the dominant control (Frost and Frost, 2008).

Samples from both Noble Olive A-1 and Cosh Mill Creek A-1 both predominately plot in the magnesian field of the Fe-Index (Figure 4.3). Due to the hypothesized provincial relation (granite rhyolite/Grenville province) of these sample suites, this was expected due to the geochemical characteristics found in post-collisional magnesian granitoids (Osborn, 1959; Frost and Frost, 2008). Analysis of samples from both holes which fall in the ferroan field suggests opaque mineral abundance and crystal size may be the controlling variables regarding potentially inflated FeOtotal (Frost et al.,

2001). Fractional crystallization resulting in the precipitation of large Fe-rich minerals 51

(see Appendix) would directly affect both geochemical composition and modal mineralogy by disproportionately representing the provided sidewall core, resulting in greater FeO concentrations.

Analysis of the Aluminum Saturation Index yielded all but two samples plotting in the metaluminous field. Samples which plotted in the peraluminous field were O-

10251 and O-10426. O-10426 was expected to plot in the peraluminous field due to the anomalous nature of the sample (97.49% SiO2), and thus was disregarded when considering the ASI. O-10251 shows an approximate median with respect to the mineral mode of plagioclase in the Noble Olive A-1 suite (Table 4.2). A drift upward into the peraluminous field could potentially be explained by a greater concentration of Ca-rich plagioclase present in the thin section, compared to what local material was analyzed via

XRF.

CHAPTER 6: CONCLUSION

Petrographic analysis of both sample suites in this study follow and support the classification scheme of Frost and Frost (2008). Samples from the southeastern Ohio basement were found to exhibit a bimodal distribution in both modal mineralogy and bulk geochemical composition, suggesting potential post-Grenville orogen extension of the basement in the study area. Plagioclase composition in Cosh Mill Creek A-1 further supports this notion. However, future research should consider focusing on trace element analysis to confirm or refute these findings.

Analysis of the results obtained from this study suggest that the bulk density and gamma ray geophysical well logging tools used in Noble Olive A-1 and Cosh Mill Creek

A-1 may be suited to differentiate among basement lithologies, providing the tools used are calibrated properly. Due to the lack of previous research on this subject, future research is suggested to determine a new approach to the creation of a predictive model, or further analyze the feasibility of this approach. Specifically, the integration of new samples within the same (or a lithologically similar) study area is recommended for consistency.

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Data: New York, Elsevier Science Publishing Company Inc., 423 p.

Sprang, H. A. van, 2000, Fundamental Parameter Methods in XRF Spectroscopy:

JCPDS-International Centre for Diffraction Data 2000, Advances in X-ray

Analysis, v.42, 10 p.

Spry, A., 1969, Metamorphic Textures: Oxford, Pergamon Press, 350 p. 56

Streckeisen, A., 1974, Classification and nomenclature of plutonic rocks:

Recommendations of the IUGS Subcommission on the systematics of igneous

rocks: Geologische Rundschau, v. 63, p. 773-786.

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Earth and Planetary Sciences, v. 13, 29 p.

APPENDIX 1: POWDERED SAMPLE PREPERATION RESULTS AND USGS STANDARD DATA

Table A-1. Sample numbers and Flux Mass (in grams) used in the XRF. Samples beginning with O = Noble Olive, those beginning with MC = Cosh Mill Creek.

Sample Name Sample Mass (g) Flux Mass (g)

O-10094 0.8504 6.0001

O-10165 0.8501 6.0005

O-10190 0.8501 6.0003

O-10234 0.8503 6.0002

O-10243 0.8505 6.0005

O-10251 0.8500 6.0006

O-10333 0.8503 6.0004

O-10356 0.8504 6.0000

O-10385 0.8502 6.0002

O-10426 0.8505 6.0002

O-10459 0.8500 6.0002

MC-7286 0.8503 6.0005

MC-7300 0.8501 6.0004

MC-7313 0.8501 6.0004

MC-7332 0.8504 6.0002

MC-7347 0.8501 6.0005 58

Table A-2. Major and trace element rock XRF geochemistry results from the USGS standard samples used in this study. Values of major elements expressed as oxides are in wt%, whereas trace elements are in ppm.

SiO2 TiO2 Al2O3 Fe2O3 MgO MnO CaO Na2O K2O P2O5 Ba Ce Rb Sr Y Zr Sample

AGV-2 59.3 1.05 16.91 6.69 1.79 0.08 5.20 4.19 2.88 0.48 1140 68 68 658 20 230 BCR-2 54.1 2.26 13.5 13.8 3.59 0.15 7.12 3.16 1.79 0.35 683 53 48 346 37 188 BHVO-2 49.9 2.73 13.5 12.3 7.23 0.13 11.4 2.22 0.52 0.27 130 38 10 389 26 172 BIR-1a 47.9 0.96 15.5 11.3 9.70 0.17 13.3 1.82 0.03 0.02 7 2 2 107 16 18 DNC-1a 47.1 0.48 18.34 1.79 10.1 0.15 11.5 1.89 0.23 0.07 118 9 5 114 18 38 DTS-2b 32.0 0.01 0.13 6.00 41.0 0.09 0.06 0.07 0.05 0.16 3 63 1 1 2 GSP-2 66.6 0.66 14.9 4.9 0.96 0.03 2.1 2.78 5.38 0.29 1340 410 245 240 28 550 QLO-1 65.6 0.62 16.2 4.35 1.00 0.10 3.2 4.22 3.60 0.25 1400 54 74 340 24 185 RGM-2 73.12 0.26 13.83 1.87 0.28 0.04 1.18 4.09 4.30 0.05 827 46 149 105 23 228 SDC-1 65.9 0.98 16.3 6.60 1.60 0.12 1.40 2.10 3.20 0.18 639 106 68 200 70 500 STM-2 60.37 0.16 18.94 5.40 0.48 0.25 1.17 8.69 4.28 0.17 610 64 113 714 57 1246 W-2a 52.57 1.06 15.38 10.80 6.43 0.17 10.91 2.20 0.62 0.14 173 23 20 195 22 93

APPENDIX 2: MANN-WHITNEY STATISTICAL ANALYSIS

Table A-3

Mann-Whitney Statistical Analysis for Bulk Density Response

Sample Response Rank Adjusted Rank n1 R1 U1 n2 R2 U2

O-10385 2.57 1 1 10 58.5 3.5

O-10094 2.60 2 3.5

O-10165 2.60 2 3.5

O-10251 2.60 2 3.5

O-10459 2.60 2 3.5

O-10426 2.61 6 6

O-10243 2.64 7 7

O-10356 2.65 8 8.5

O-10190 2.70 10 10

O-10333 2.75 11 12

MC-7332 2.65 8 8.5 4 46.5 36.5

MC-7286 2.75 11 12

MC-7313 2.75 11 12

MC-7300 2.80 14 14

Table A-4

Mann-Whitney Statistical Analysis for Gamma Ray Response

Sample Response Rank Adjusted Rank n1 R1 U1 n2 R2 U2

MC-7286 30 1 1 5 15 0

MC-7332 35 2 2

MC-7300 42 3 3.5

MC-7347 42 3 3.5

MC-7313 45 5 5

O-10190 110 6 6 11 121 55

O-10165 115 7 7

O-10234 120 8 8

O-10356 130 9 9

O-10333 135 10 10

O-10459 262 11 11

O-10426 355 12 12

O-10251 382 13 13

O-10243 395 14 14

O-10094 400 15 15.5

O-10385 400 15 15.5

Table A-5

Mann-Whitney Statistical Analysis for PE Response

Sample Response Rank Adjusted Rank n1 R1 U1 n2 R2 U2

O-10426 1.9 1 1 11 75 9

O-10251 2.0 2 2

O-10094 2.1 3 3

O-10190 2.5 4 4

O-10165 2.9 5 5.5

O-10385 2.9 5 5.5

O-10243 3.0 7 8

MC-7286 3.0 7 8 4 45 35

MC-7313 3.0 7 8

O-10459 3.1 10 10

O-10234 3.2 11 12

O-10333 3.2 11 12

O-10356 3.2 11 12

MC-7300 3.9 14 14

MC-7332 4.5 15 15

APPENDIX 3: CROSSPLOTS OF GEOPHYSICAL TOOL RESPONSE VS. MINERAL

VOLUME/WEIGHT-PERCENT ELEMENT OXIDE

Photoelectric Response vs. Mineral Volume

Bulk Density vs. Mineral Volume

Gamma Response vs. Mineral Volume

Neutron Porosity Response vs. Mineral Volume

Photoelectric Response vs. Element Oxide Weight Percent

Measured Bulk Density vs. Element Oxide Weight Percent

Gamma Response vs. Element Oxide Weight Percent

100

Neutron Porosity vs. Element Oxide Weight Percent

101

102

103

104

105

106

APPENDIX 4: THIN SECTION SCANS IN PLANE AND CROSSED POLARIZED LIGHT

5 mm

107

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108

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109

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