Mesa Antero, Chaffee County, Colorado Upper Arkansas River Valley

Geologic Setting c/o Mesa Antero Water Assoc. (MAWA)

Jay C. Close Nathrop, Colorado

Presentation to MAWA Board and Members January 3, 2014

Objectives / Background

• Provide an overview of Upper Arkansas River Basin, Colorado geology, with specific reference to MAWA geologic setting – Utilize selected technical references from publicly available

literature / Internet resources

• Basic understanding of MAWA geology may impact the Board’s actions regarding future water supply – Water utilization considerations are here to stay – Serve as background for water rights questions / investigations – May impact future system maintenance / upgrades – Unforeseen circumstances?

2

Observations / Conclusions

• Upper Arkansas Valley geologic setting – northern Rio Grande Rift (down-dropped fault valley) occupied by

structurally-controlled Arkansas River – Flanked by mountain range uplifts (Sawatch to west; Mosquito to east)

split by the Rift, from which geologically very young glacial outwash / alluvium and underlying basin fill were sourced

• MAWA water supply – Aquifer: glacial outwash gravels; secondarily from deeper basin fill? – Chemistry: sodium bicarbonate fresh water; total dissolved solids very

low (TDS often <250 mg/liter) – Primary water source: surface infiltration; seasonal water table levels

highest after snow melts – Apparent age: variable; some water younger than 1953, some older;

time- and location-specific

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Central Colorado topography: reflection of geologic setting

Upper Arkansas

Valley

http

s://

map

s.go

ogle

.com

/

4

http

://e

n.w

ikip

edia

.org

/wik

i/Rio

_Gra

nde_

Rift

Upper Arkansas

Valley South Park

Wet Mtn. Valley

San Luis Valley

5

Colorado Plateau: flanked by Rio Grande Rift to east

Centers of igneous activity

San Juan Mtns

http

://w

ww

2.na

ture

.nps

.gov

/geo

logy

/edu

catio

n/fo

os/p

late

au.p

df

Upper Arkansas

Valley

6

Central Colorado topography: influence of Colorado Plateau / Rio Grande Rift on geologic setting

South Park

Northern Rio Grande

Rift (San Luis Valley)

Upper Ark.

Valley

San Juan Mtns

Volcanic Field

Gunnison Plateau

http

s://

map

s.go

ogle

.com

/

Wet Mtn

Valley

Raton Basin

San Juan Basin

Piceance Basin

39 Mile Volcanic

Field

Denver Julesburg

Basin

7

Geologic Time Scale, Cenozoic Era ht

tp:/

/pub

s.us

gs.g

ov/f

s/20

07/3

015/

fs20

07-3

015.

pdf

Ma = millions of yrs

8

Fault locations/ages-central Chaffee County, Colorado ht

tp:/

/dnr

web

map

gdev

.sta

te.c

o.us

/cgs

onlin

e/ BV

Nathrop

Salida

Mesa Antero

ka = thousands of yrs

9

central Chaffee County topography ht

tps:

//m

aps.

goog

le.c

om/

Mesa Antero

Salida

Nathrop

Centerville

10

Mt Princeton Chalk Cliffs adjacent to northern Sawatch fault zones

Kaolinite-white clay weathering from white granite •Chalk Cliffs formed by geothermal waters

migrating up along / near Sawatch fault zones: Mt Princeton Hot Springs ! Late Sept 2013 photo, view ~NW

http

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eosu

rvey

.sta

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/Site

Colle

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umen

ts/E

nerg

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eoth

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te1_

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titiv

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rmal

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ap.p

df

11

Mesa Antero topographic detail

http

://w

ww

.usg

s.go

v/pu

bpro

d/

~1 mi

T51N R8E

12

Geologic Map, Mesa Antero area ht

tp:/

/ngm

db.u

sgs.

gov/

Prod

esc/

prod

desc

_378

4.ht

m

Centerville

Quaternary Qpo: Pinedale glacial outwash Qi: Illinoisan(?) glacial outwash Qn: Nebraskan(?) glacial alluvium Tertiary Td: Dry Union Fm.

~1 mi

Roadcut on switchback eastern end

of 261P (Ouray): excellent example

of Qn underlain

by Td

13

Mesa Antero area geologic setting: Quaternary alluvium / glacial

outwash underlain by Tertiary Dry Union Fm basin fill

Mesa Antero

http

s://

map

s.go

ogle

.com

/

14

Mesa Antero geologic setting

Aug 2013 photo, view ~W From Aspen Ridge

Dry Union Fm.

Sawatch fault zone

Mesa Antero

Dry Union Fm. badlands

NW of Salida

15

Glacial outwash, Mesa Antero

16

Dec 2013 photo Ouray Road

NW Sec 17-T51N-R8E

US Geological Survey Upper Arkansas River water report

http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf 17

http

://p

ubs.u

sgs.

gov/

sir/2

005/

5179

/pdf

/SIR

2005

-517

9.pd

f

BV

Nathrop

Generalized surface geology Water table altitude/configuration, Sept 2003

Mesa Antero

18

Cross section of ground water flow, northwest of Salida ht

tp:/

/pub

s.usg

s.go

v/sir

/200

5/51

79/p

df/S

IR20

05-5

179.

pdf

19

Water level / water quality monitors, selected stream gauges ht

tp:/

/pub

s.us

gs.g

ov/s

ir/20

05/5

179/

pdf/

SIR2

005-

5179

.pdf

Mesa Antero

20

Aquifer Characteristics, Upper Arkansas Valley

http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf 21

Depth to Water, Sept 2003

Mesa Antero

http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf 22

Historic Water Well Levels

http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf 23

Water Level Changes, July 2002-July 2003

http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf

Mesa Antero

24

Water Quality, alluvium/outwash, Sept-Oct 2001 ht

tp:/

/pub

s.usg

s.go

v/sir

/200

5/51

79/p

df/S

IR20

05-5

179.

pdf

25

Ground Water Ages via Tritium Analyses

• Tritium: hydrogen isotope • Above-ground nuclear weapons testing in 1950’s-1960’s

greatly increased atmospheric tritium concentrations, hence currently provide an excellent chronological marker for geologically extremely young systems

• Tritium half-life ≈ 12.32 yrs • Ground water age estimation via tritium concentrations in

specially collected samples • Qualitative ages: pre-modern <1953, post-modern ≥1953 • Quantitative ages via half-life techniques

http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf 26

Water level and water quality sample wells http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf

27

Apparent Mean Ages (tritium reference) of Ground Water Recharge, Browns Creek – Chalk Creek area

‘Because water level altitudes at wells 55, 58, and 59 were high than the altitude of Browns Creek, the stream reach is probably a gaining reach and the ground water

recharge is likely from precipitation.’ ‘The range in ages of ground water recharge for wells 55, 58 and 59 was not definitive…’

‘…it is likely that the shallow ground water (wells 58 and 59) was recharged more recently than the deeper ground water (well 55).’

http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf p. 37 28

Selected References Upper Arkansas Valley, Colorado geology

• Hydrogeology and Quality of Ground Water in the Upper Arkansas River Basin from Buena Vista to Salida, Colorado, 2000-2003 http://pubs.usgs.gov/sir/2005/5179/pdf/SIR2005-5179.pdf

• Roadside Geology of Colorado (2nd ed.) http://mountain-press.com/item_detail.php?item_key=34

• Geology and Mineral Deposits of the Poncha Springs SE Quadrangle, Chaffee County, Colorado http://pubs.usgs.gov/pp/0829/report.pdf

• Geologic Map of the Poncha Springs Quadrangle, Chaffee County, Colorado http://ngmdb.usgs.gov/Prodesc/proddesc_3784.htm

• Geologic Map of the Poncha Springs NE Quadrangle, Chaffee County, Colorado http://pubs.usgs.gov/pp/0626/report.pdf

• Reconnaissance Geologic Map of the Buena Vista Quadrangle, Chaffee and Park Counties, Colorado http://pubs.er.usgs.gov/publication/mf657

• Geologic Map of the Buena Vista East Quadrangle, Chaffee County, Colorado http://geosurveystore.state.co.us/p-612-buena-vista-east-quadrangle-chaffee-county.aspx http://www.geohaz.com/downloads/GEOLOGIC%20MAPS/COLORADO/BUENA%20VISTA%20East/OF%2004-4%20Buena%20Vista%20East%20Booklet.pdf

• Road and Riverside Geology of the Upper Arkansas Valley….Leadville to Cañon City Tom Karnuta, Salida, Colorado. http://cozine.com/1995-august/geology-of-the-upper-arkansas-valley-by-tom-karnuta/

• High Plains to Rio Grande Rift: Late Cenozoic Evolution of Central Colorado http://fieldguides.gsapubs.org/content/3/59.full

• Insights Into the Structural Development of the Upper Arkansas Valley: The Influence of Pre-Existing Structure and Implications of Basin Geomorphology. Richard Smith, Nathrop, Colorado. https://gsa.confex.com/gsa/2013AM/webprogram/Paper230081.html

• Mt. Princeton Geothermal Presents Energy Plan. Fred Henderson III, Mt Princeton Geothermal LLC. http://www.themountainmail.com/news/article_88772894-29df-11e3-99af-001a4bcf6878.html

• Analysis of Borehole Temperature Data from the Mt. Princeton Hot Springs Area, Chaffee County, Colorado http://www.searchanddiscovery.com/documents/2013/80327morgan/ndx_morgan.pdf

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