ES322 Geomorphology Lab Exercise Estimating Historic Weathering Rates in Western Oregon from Tombstone Morphology Part 1 Data Collection Introduction Rock weathering at the Earth s surface forms the basis for regolith production and is a fundamental process that shapes the landscape over time Rates and degrees of rock weathering at any given location are controlled by climate aspect temperature precipitation rock types composition and texture organic activity moss and lichen growth and style of chemical physical weathering processes e g freeze thaw hydrolosis etc Objective The objective of this lab is to use tombstone morphology in the Monmouth area to estimate historic weathering rates in the region Tombstones represent important historic weathering indicators as they provide data on known exposure ages and rock composition two important variables necessary for understanding weathering conditions at the Earth s surface Methodology The class will visit the local Monmouth cemetery south of town and collect the following data on Table 1 Observation Date todays date Date of Death from tombstone Exposure Time yrs observation date Death date Rock Type igneous granite basalt andesite sedimentary sandstone limestone metamorphic marble gneiss Crystal grain size mm size of mineral grains textural characteristics Mineral composition quartz feldspar plagioclase hornblende calcite Surface Roughness to Touch 1 smooth 2 slightly rough 3 moderately rough 4 highly rough Polish Condition 1 highly polished 2 moderately polished 3 poorly polished 4 unpolished Epitaph Inscription Quality Rating 1 11 observed from 50 cm viewing distance see attached sheets 0 recent sharp edge inscriptions 1 roughened polish 2 roughened surface to touch but perfectly legible 9 inscription barely readable 10 inscription barely seen 11 inscription totally removed Inscription Aspect Azimuth azimuth direction the inscription of the tombstone faces Inscription height above ground surface cm Top Stone Thickness right mm measured using meter stick calipers Top Stone Thickness left mm Top Stone Thickness middle mm Average Top Stone Thickness mm Basal Stone Thickness right mm measured using meter stick calipers Basal Stone Thickness left mm Average Basal Stone Thickness mm Weathering Loss Avg bottom thickness Avg top thickness mm Lichen Moss Cover Lichen Diameter mm Percent cover ES322 Tombstone Weathering Data Sheet Death Observation Date Date Oldest Listed Location Survey Team Members Rock Type granite gabbro marble limestone sandstone gneiss Surface Roughness 1 smooth 2 slightly rough 3 moderately rough 4 highly rough Minerals calcite quartz potassium feldspar plagioclase feldspar amphibole biotite Polish Condition 1 highly polished 2 moderately polished 3 poorly polished 4 unpolished Exposure Rock Time yrs Type Avg Crystal Mineral Surface Polish Grain Composition Roughness Condition Size List mm Inscription Inscription Top Stone Top Stone Top Stone Avg Top Rating 0 Aspect Thickness Thickness Thickness Thickness new 11 cm Azimuth Right cm Middle cm Left cm oliterated Basal Basal Avg Stone Stone Basal Thickness Thickness Thickness Right cm Left cm cm Avg Stone Lichen Lichen Recession Moss Diameter Bottom Cover Top cm mm Comments ES322 Geomorphology Tombstone Weathering Exercise Task List and Instruction Sheet Task 1 Take a class field trip to the Monmouth Cemetary make observations and collect data on tombstone ages lithology and characteristics Task 2 In teams of 2 3 collect data on data table compile observations in a MS Excel spreadsheet posted on class web site and send to student team leader for group compilation Task 3 Combine this year s tombstone observations spreadsheets with previous year s data on class web site to increase the total number of sample observations and increase the veracity of the statistical analysis Task 4 Using Excel or graph paper plot the follow tombstone weathering relationships A Provide a tabled summary of your total observations the number of samples according to tombstone lithology B Inscription Rating Graph one graph two lithologies with different symbols a Inscription Rating Y Axis vs Exposure Age X Axis for granite lithology b Inscription Rating Y Axis vs Exposure Age X Axis for limestone calcareous sandstone marble lithology C Surface Roughtness Graph one graph two lithologies with different symbols a Surface Roughness Y Axis vs Exposure Age X Axis for granite lithology b Surface Roughness Y Axis vs Exposure Age X Axis for limestone calcareous sandstone marble lithology D Using Excel or visual inspection draw a best fit regression line to each of the plots on your graphs in 4 A and 4 B above Task 5 Using MS word write a 2 page lab report with your findings address the following questions A Describe discuss your observations of tombstone Inscription Rating and Surface Roughness in the context of exposure age Do either one of these weathering metrics effectively correlate with time since tombstone exposure B Describe and discuss the differences in relative rock strength and resistance to weathering as related to tombstone lithology How to the granite and limestone lithologies hold up to weathering over time Are they the same or different Present your discussion and refer to your results in Task 4 above C List and discuss the implicit assumptions and sources of error that could be associated with your observations in items 5A and 5B D Discuss any other aspects of tombstone weathering or favorite concepts related to the ES322 field trip to the cemetery