Skip Links

USGS - science for a changing world

Open-File Report 2008-1380

Prepared in cooperation with the U.S. Bureau of Indian Affairs, Hopi Tribe, and the Navajo Nation

Geologic Maps and Cross Sections of the Tuba City Open Dump Site and Vicinity, With Implications for the Occurrence and Flow of Ground Water

By James K. Otton, Raymond H. Johnson, Robert J. Horton

Abstract

Thumbnail of publication and link to PDF (33.5 MB)

This report is designed to make available to interested parties geologic and limited hydrologic and geochemical information about the Tuba City Open Dump (TCOD) site. This information has been gathered during studies of the site from January to September 2008. Mapping by the authors and construction of cross sections show that a section of gently northeast-dipping Jurassic sedimentary rocks underlies the TCOD and vicinity. Low mesas in the area are capped by variably cemented gravels and siliceous limestones. Surficial sediments are composed of eolian sand and fluvially reworked eolian sand that overlie bedrock underneath the TCOD. Nearby Pasture Canyon is underlain by fluvial and floodplain sediment consisting of sand and silt. Shallow ground water of the water-table aquifer at the TCOD moves westward through the surficial sediment and the underlying weathered bedrock to Pasture Canyon then southward along the canyon. A fracture zone extends up the wash that passes just to the north of the TCOD and brings deeper ground water of the N-aquifer to the water-table aquifer.

Bedrock consists of the Jurassic Navajo Sandstone composed of thick sections of eolian crossbedded sandstone with lesser laterally discontinuous layers of silty sandstone, siltstone, and limestone. Below the Navajo Sandstone is a section informally known as the Kayenta Formation-Navajo Sandstone transition zone. It is composed of calcareous sandstone, silty sandstone, siltstone, and limestone beds that intertongue with crossbedded sandstone. The finer grained rocks in both major bedrock units form aquitards that limit downward movement of ground water. The water-table aquifer is perched on these aquitards, which locally occurs beneath the two open dumps that form the TCOD site. A monocline occupies the position of Pasture Canyon west of the TCOD. Fractures likely related to the monocline are exposed in several localities.

Deep ground waters consist of dilute calcium-bicarbonate waters low in all trace elements. Shallow ground water is variably affected by near-surface processes, which add varying amounts of sodium, chloride, sulfate, and trace elements. Locally, human influences, such as the TCOD, affect shallow ground-water chemistry.

First posted January 15, 2009

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Otton, J.K., Johnson, R.H., and Horton, R.J., 2009, Geologic maps and cross sections of the Tuba City open dump site and vicinity, with implications for the occurrence and flow of ground water: U.S. Geological Survey Open-File Report 2008–1380, 78 p.



Contents

Abstract

Introduction

Methods

Geology of the Tuba City Open Dump and nearby Pasture Canyon

Cross Sections Map Area

References Cited

Appendix 1

Appendix 2


Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/of/2008/1380/
Page Contact Information: Contact USGS
Page Last Modified: Wednesday, December 07, 2016, 09:38:08 PM