Part 3: Glacial moraine chronology provides a basis for evaluating the timing and rates of deglaciation for late glacial and Holocene paleoglaciers in the

Peruvian Andes. Rates of deglaciation were calculated for paleoglacier volumes on both the western side of the Quelccaya Ice Cap and the northwest sideof the Cordillera Vilcanota, Perú. The late glacial episode of deglaciation on the west side of Quelccaya is coincident with rapid deglaciation in the CordilleraBlanca of north central Perú that occurred during the Younger Dryas interval, out of phase with glaciation in the North Atlantic region (Rodbell and Seltzer,2000). The fastest rates of deglaciation were calculated for the youngest paleoglaciers, corresponding to the last few centuries. These rates fall within therange of modern rates measured on the Quelccaya Ice Cap, interpreted as evidence of enhanced atmospheric temperatures (Thompson, 2000). Applyingthe maximum modern deglacial rates to the late glacial ice volumes results in deglaciation over a few centuries, consistent with lake-core evidence. Theseresults imply that rates of deglaciation may fluctuate significantly over time, and that high rates of deglaciation may not be exclusive to the late 20th century.

•1999 glacier surface from

differential GPS survey

•1999 glacier surface from

differential GPS survey

•1999 glacier surface from

differential GPS survey

DEM (1:25,000)DEM (1:25,000)

333

Glacier Aspect

DEM

volume

change

1962-99

mean area

1962-99

surface

lowering

(103 m3) (103 m2) (m)

Queshque Main SW 48951 2197 22

Queshque East E 2215 407 5

Mururaju S 5441 1079 5

0

5

10

15

20

25

240 245 250 255 260

Solar radiation (Wm-2)

Su

rface

low

eri

ng

(m)

Queshque

Main (SW)

Mururaju (S) Queshque

East (E)

+0.4+0.4

R2

= 0.65

0.0

0.5

1.0

1.5

2.0

2.5

0 20 40 60Glacierized area (%)

Ma

xQ

Me

an

Q

Querococha

OllerosChancos

LlanganucoParon

c. Callejon de Huaylas

Terminus

recession

-700

-550

-400

-250

-100

1930 1950 1970 1990 2010

(m)

0

5

10

15

20

25

30

35

40

(m/y

r)

(m)(m/yr)

4 km0 22

Contour interval = 200 m

0 200200 400 m

Querococha watershed

Yanamarey catchment

GlaciarYanamarey

GlaciarYanamarey

YANdischarge

YANdischarge

Q3discharge

Q3discharge

4000

4400

4400

4800

4400

4800

Querococha3980

Querococha3980

5322

5237

5197

Q1discharge

Q1discharge

Q2discharge

Q2discharge

5000

GlaciarYanamarey

4800

5237

50

0099

98

97

88

82

73

6248

1939

*

80 km40040

Callejon de Huaylas

78

00

'°

77

20

'°

9 50'°

9 10'°

8 50'°

6259

RioSanta

Olleros

6395

6125

6162

6395

4000

3000

4000

5000

5000

4000

3000 2000

4000

Llanganuco

Paron

SANTA2

CONOCOCHA

Cord

illera

Negra

Pachacoto

Colcas

Quilcay

Huaraz

Marcara

Llullan

Huallanca

Tuco

6768

77

00

'°

Q3

Yanayacu

Negra1

Negra2

SANTA1

Buin

Cord

illera

Bla

nca

Paltay

Ranrahirca

Kinzl

JANGAS

Anta

Negra Low

SANTA LOW

Contour interval = 1000 m

Glacierized

Watershed

Lake

Yan GlacYANQ2Q1Q3Below Quero

CO2-

+ HCO-

SO4

2-

Cl-

Ca2+

Mg2+

Na+

+ K+

SO

42-

+C

l-

Ca 2

++

Mg 2

+

3. Tributaries of Rio Santa

2. Downstream confluence

1. Glacier watershed

-11° S

°C per decade

-11° S

°C per decade

4600

4700

4800

4900

5000

5100

5200

5300

5400

5500

5600

0 0.5 1 1.5 2 2.5 3

Glacier area (km2)

Ele

va

tio

n(m

)

Queshque Main

Queshque East

Mururaju

(SW)

(E)

(S)

4600

4700

4800

4900

5000

5100

5200

5300

5400

5500

5600

0 0.5 1 1.5 2 2.5 3

Glacier area (km2)

Ele

va

tio

n(m

)

Queshque Main

Queshque East

Mururaju

(SW)

(E)

(S)

Tropical Peruvian glaciers in a changing climate:Forcing, rates of change, and impact to water supply

Tropical glaciers are intriguing and presently rapidly disappearing components of the cryosphere thatliterally crown a vast ecosystem of global significance. They are highly sensitive to climate changesover different temporal and spatial scales and are important hydrological resources in tropicalhighlands. Moreover, an accurate understanding of the dynamics and climate response of tropicalglaciers in the past is a crucial source of paleoclimatic information for the validation and comparisonof global climate models. We have studied both present-day glacier recession and field evidence ofpast episodes of deglaciation in Perú to test hypotheses related to this important climatically forcedprocess in the developing Andean region. Modern glacier recession raises the issues of the nature ofclimatic forcing and the impact on surface water runoff. While rates of contemporary glacier recessionappear to be accelerating, careful analysis of the timing and volumetric extent of deglaciation fromLate Glacial and Holocene moraine positions provides a historical comparison with importantimplications for understanding glacial-to-interglacial transitions. Our research incorporates threespecific parts: an analysis of the spatial variability and climatic forcing of late 20th century glacierrecession in the Queshque massif of the southern Cordillera Blanca, Peru; an evaluation of thehydrological significance of glacial meltwater with respect to streamflow in the Cordillera Blancaregion; and an evaluation of the rate and extent of deglaciation during the late-Pleistocene andHolocene compared to modern glacier recession in the Cordillera Vilcanota/Quelccaya. We reviewour results in the context of outlining a vision for using glacial-environmental assessment as a focalpoint to investigate both physical and human dimensions of climate change.

(1)(2)

(3)

Bryan G. Mark (1) & Jefferey M. McKenzie (2)(1) The Ohio State University, Department of Geography & Byrd Polar Research Center, Columbus, OH 43210,(2) Syracuse University, Department of Earth Sciences, Syracuse, NY 13210,

mark.9@osu.edujmmckenz@syr.edu

Mururaju(S)Queshque

Main(SW)

QueshqueEast (E)

5688

5680

5403

4800

5000

5000

54004600

Mururaju(S)Queshque

Main(SW)

QueshqueEast (E)

5688

5680

5403

4800

5000

5000

54004600

Mururaju(S)Queshque

Main(SW)

QueshqueEast (E)

5688

5680

5403

4800

5000

5000

54004600

Lagunas Queshque

Queshque(5680)

Mururaju(5688)

(SPOT image 1997)

6 0 6 12 Kilometers

Summer Solstice7900 - 87007600 - 79007400 - 76007100 - 74006700 - 71006300 - 67005800 - 63005300 - 58004600 - 53002800 - 4600No Data

Wm-2

Winter Solstice6600 - 75006200 - 66005800 - 62005500 - 58005100 - 55004600 - 51004100 - 46003500 - 41002800 - 35001000 - 2800No Data

Wm-2

N

EW

S

225

230

235

240

245

250

255

260

265

Quesh Main (SW) Quesh East (E) Mururaju (S)

Wm

-2

1962 area

1999 area

1962-99 area

-2.0

-1.0

0.0

1.0

2.0

1950 1960 1970 1980 1990 2000

Year

ºC

-2.0

-1.0

0.0

1.0

2.0

1950 1960 1970 1980 1990 2000

Year

mm

A 30m DEM was generated from 1:25,000 and1:100,000 maps and used to model insolationreceipt to the surface. Integrated clear-sky valuesof global radiation for and solstices(right) show seasonal shading differences. Asimple transmittivity model using the DEMindicates solar radiation related to alteredcloudiness was not a predominant climatic forcingof mass loss.R : Mean annual clear sky solar radiation

flux (Wm-2) averaged over the 3 different areas foreach of the glaciers, representing the surfaceareas for both 1962 and 1999, as well as the areavacated by the ice between these dates (1962-99).The mean annual total radiation is greatest overthe east-facing glacier.

winter summer

( ight, top)

0

100

200

300

400

500

600

700

800

900

1000

1100

08-

Jun-

98

06-

Jul-

98

10-

Aug-

98

19-

Sep-

98

19-

Oct-

98

28-

Nov-

98

29-

Dec-

98

04-

Feb-

99

05-

Mar-

99

23-

Apr-

99

02-

Jun-

99

25-

Jun-

99

Q1Q2Q3

-400

-300

-200

-100

0

100

200

300

400

500

600

700

(mm

)

-4

-3

-2

-1

0

1

2

3

4

5

6

7

(C)

PMelt

Qt (YAN)T

a. Yanamarey

b. Querococha

Ca2+

Mg2+

Na+

+ K+

CO3

2-+ HCO3

-

SO4

2-

Cl-

SO 4

2- +C

l- C

a 2++

Mg 2+

Cord Blanca

Rio Santa

Cord Negra

Part 2: Understanding the impact that melting glaciers are having on water resources in the Callejon de

Huaylas requires quantifying the annual impact of glacier mass loss to the main river channel. We havetraced melt water hydrochemically from the small Yanamarey glacier catchment through the Querocochawatershed and in the downstream tributaries of the Rio Santa with different degrees of glacier coverage.

(Above) Case study location maps of successively larger scale: Callejon de Huaylas, a watershed of ~5000 km draining the Cordillera Blanca, Perú, to the upper Rio Santa.Stream gauge and sample locations are identified; Querococha watershed, 60 km , showing the discharge and water sampling points; Yanamarey catchment, 1.3 kmbetween 4600 m and 5300 m, 75% of which is covered by glacier ice. The shaded region shows the outline of Glaciar Yanamarey in 1982, with contours and a center-line toshow distance from headwall with 100 m intervals (after Hastenrath and Ames, 1995a). Terminus positions are mapped onto a common datum, based on surveys for 1939,1948, 1962, 1973, 1982, 1988, 1997, 1998, and 1999. The latter three positions were mapped using differential GPS. The cumulative terminus recession from the 1939position is shown (m) on the inset graph as solid line, with solid rectangles for years with corresponding terminus position mapped (data from A. Ames, personalcommunication, 1998), along with average recession rate between years with mapped termini (in meters/year). Asterix marks the location of a weather station, where dailytemperature and monthly precipitation were recorded discontinuously from 1982.

2

2 2

(Above) Hydrological and climatological data from the successively largercatchments of the case study (see Fig. 1): (a) observational data from the Yanamareyglacier catchment, including monthly measurements of specific discharge (Qt) (mm)from YAN plotted with the monthly precipitation totals (P) (mm) and monthly averagetemperature (T) (degrees C) sampled over the 1998-99 hydrological year, plotted withthe glacier melt (Melt) calculated from a simplified hydrological mass balance; (b)specific discharge data from locations in the Querococha watershed plotted withmonthly precipitation at the Querococha gauge (both in mm), on the same scale as(a); (c) magnitude and variation of annual stream discharge with percentage ofglacierized area in the Río Santa tributaries, shown by ratio of maximum monthlydischarge to mean monthly discharge (max Q / mean Q); labeled data pointscorrespond to gauge locations shown on map.

Glacierized % (1962) (1997)Paron 55 52Llanganuco 41 36

Colcas 20 18

Cedros 22 18Chancos 25 22

Olleros 12 10Querococha 6 3

(Above) Piper plot of major ion chemistry from the YAN-Querococha watershed. Q3 is on a mixingline between the glacial snout and Q1, with a relative contribution of 50% from each end member.The size of each symbol is proportional to TDS.

(Above) Piper plot of major ion chemistry from the averaged end-members in the Callejon deHuaylas watershed. The Rio Santa is on a mixing line between the glacierized CordilleraBlanca tributaries and non-glacierized Cordillera Negra tributaries, with a relative contribution of66% from the Cordillera Blanca. The size of each symbol is proportionate to TDS.

Part 1: We use a combination of aerial photogrammetry, satellite imagery,

and differential GPS mapping to quantify the volume of ice lost between AD1962 and 1999 from 3 glaciers of different aspect. A heuristic sensitivity analysisindicates the 9.3 Wm required to melt the observed ice loss can be explainedby a 1K rise in temperature and 0.14 gkg increase in specific humidity.

-2

-1

0

50

100

150

200

250

1963-1978 1978-1983 1983-1991

Rivers

Glacier

Lakes

Equator 0

South America

10

0

10

20Kilom

eters

Cordillera Vilcanota

QuelccayaIce Cap

Upismayo Valley

HuancaneValley

Ausengate(6372 m)

(5645 m)

N

EW

S

Huancané Valley

Lake

Moraine

Stream

Modern Ice

Ice1

Ice2

Ice3

Upismayo Valley

1 0 1 2 3 4 5 Kilometers

Quelccaya Ice Cap

L. Paco CochaL. Acconcancha

Han

cane

Valle

y

10,870 � 72

10,910 � 160

12,240 � 170

270 � 80

2670 � 95

9980 � 255

12,230 � 180

11,183 � 109

2 0 2 4 8 10 Kilometers

L. Comercocha

Q.Ja

laco

cha

Q. Upismayo

L. Casercocha

NevadoAusengate(6372 m)

13,380 � 150

4450 � 45

10,362 � 73

2830 � 70328 � 46

CordilleraBlanca

PERU

80 W° 72 W°

>4000 m in elevation

Lima

8 S°

16 S°

0 S°

CordilleraVilcanota

View of Ausengate and the Cordillera Vilcanota from theUpismayo valley (below). Landsat image draped overDEM of the Vilcanota, viewed from NW (above).

Accelerating rates of deglaciation for the Qori Kalisglacier (photo above) in 10 km yr , calculatedfrom terrestrial and aerial photogrammetry(Brecher and Thomas, 1993).

-5 3 -1

Glacier Volume Deglacial Interval (yrs) Deglacial Volume (km3) Deglacial Rate (10

-5km

3/yr)

(km3) (small) (large) (small) (large) (small) (large)

Upismayo Valley

ice3 1.17 5150 4400 3746 12073 11605 10950 0.43 1.31 3.56 3.71 3.93 25.44 29.77 34.97

ice2 0.74 2504 2135 1823 4986 4651 4472 0.19 0.88 3.81 4.09 4.25 35.14 41.22 48.27

ice1 0.55 489 384 279 0.55 0.69 112.47 143.23 197.13 141.10 179.69 247.31

mod 0.14

Huancané Valley

H3 0.43 3778 2400 1511 0.09 0.57 2.38 3.75 5.96 15.09 23.75 37.72

H2 0.34 1806 700 617 9787 9130 8133 0.34 0.48 3.47 3.72 4.18 26.58 68.57 77.80

H1 0.19 492 290 0.19 0.33 38.62 65.52 --- 67.07 113.79 ---

mod 0.14

Moraine chronology in the Upismayo and Huancané valleys allows for a rates of deglaciation to be calculated usingpaleoglacier volumes estimated from a digital elevation model (DEM). Radiocarbon ages for moraine features are shown inthe site maps above (from Goodman et al., 2001). Three paleoglacier volumes were reconstructed for each valley, asshown with contour lines in figures to left (Mark et al., 2002). The estimated rates are tabulated above, and shown in bargraphs, as explained below.

(km ) of each reconstructed paleoglacier is calculated using gridded-model surfaces and the DEM. Modern glaciervolume ('mod') was estimated from surface area by the formula V=28.5 S (after Chen and Ohmura, 1990).

(yrs) represents the conceivable time range over which the paleoglacier deglaciated from successively lessextensive end moraine positions. The interval is presented as a mean surrounded by the one-sigma range in calibratedradiocarbon ages. Where available radiocarbon dates include more than one constraining age for a moraine, the maximumand minimum possible intervals are provided as 'large' and 'small' intervals respectively. (km ) representsthe volume lost from the paleoglacier in 2 possible deglacial scenarios: a 'large' volume from complete deglaciation; and a'small' volume considering only the volume lost between successive moraine positions. (10 km yr ) iscalculated by dividing the deglacial volume by the deglacial interval, such that the 'small' rate equals 'small' volume dividedby 'large' interval, and 'large' rate equals 'large' volume divided by 'small' interval.

VolumeDeglacial

interval

Deglacial volume

Deglacial rate

3

1.36

3

-5 3 -1

The increments in volume (multiple of the modeled volume) and deglacial interval (number of years) needed for the modeledpaleoglaciers to equal the most recent rates of deglaciation are tabulated to right.

0

20

40

60

80

100

120

H3 H2 H1

small

large

0

50

100

150

200

250

300

ice3 ice2 ice1

small

large

Qori Kalis glacier

Paleoglacier Volume needed(x modeled)

Time needed(yrs)

Upismayo Valley

H3 5-8 210-370

H2 20-40 130-230

Huancané Valley

Ice3 3-5 500-630

Ice2 20-25 110-150

Lake

Moraine

Stream

Modern Ice

H1

H2

H3

Queshque East (E)

Queshque Main (SW)

Mururaju (S)

Pleistocene moraines,Cordillera Blanca

Acknowledgments

Kathy Welch, Anne Careyand Berry Lyons aregratefully acknowledged forfacilitating laboratoryanalyses at Ohio StateUniversity. Don Siegelsupported laboratory work atSyracuse University. Initialfield work was conductedwhile BGM was supportedon a U.S. FulbrightScholarship, 1997-98.

Aerial photos (left) and satellite imagery(above) were used to map glacier extent in1962 and 1997. Digital glacier surfaceswere reconstructed with photogrammetryand differential GPS. Contour map (upperright, interval = 200m) of the glacierizedareas on the Queshque massif (photos of 3glaciers to left). Three tones of shadingrepresent: 1999 glacier areas of theglaciers (light grey); the 1962 areasmapped from aerial photography (blue);and other areas mapped from 1997 SPOTimagery (dark grey). Dots represent GPS-mapped surface elevations from 1999survey. Dashed lines are ridges separatingthe major drainages. Digital elevationmodel (DEM) generated from digitized1:25,000 contour lines (lower right).

ReferencesBrecher, H. and L. G. Thompson, 1993: Measurement of the retreat of Qori Kalis glacier in the tropical Andes of Peru by terrestrial photogrammetry.

, 1017-1022.Chen, J., and A. Ohmura, 1990: Estimation of alpine glacier water resources and their change since the 1870s.

; the Water Cycle (Proceedings of two Lausanne Symposia, August, 1990). IAHS Publ. No. 193, 127-135.Hastenrath, S., Ames, A., 1995. Recession of Yanamarey Glacier in Cordillera Blanca, Peru, during the 20th century. Journal of Glaciology 41(137), 191-196.Goodman, A.Y., Rodbell, D.T., Seltzer, G.O., Mark, B.G., 2001. Subdivision of glacial deposits in southeastern Peru based on pedogenic development andradiometric ages. Quaternary Research 56(1), 31-50.

Thompson, L. G., 2000: Ice core evidence for climate change in the Tropics: implications for our future. , 19-35.

Photogrammetric Engineering & Remote SensingHydrology in Mountainous Regions. I-

Hydrological Measurements

Quaternary Science Reviews

59(6)

19

Mark, B.G., Seltzer, G.O., Rodbell, D.T., Goodman, A.Y., 2002. Rates of deglaciation during the last glaciation and Holocene in the Cordillera Vilcanota-Quelccaya Ice Cap region, Southeastern Perú. Quaternary Research 57(3), 287-298.Mark, B.G., Seltzer, G.O., 2003. Tropical glacier meltwater contribution to stream discharge: a case study in the Cordillera Blanca, Peru. Journal ofGlaciology 49(165), 271-281.Mark, B.G., Seltzer, G.O., 2005. Recent glacial recession in the Cordillera Blanca, Peru (AD 1962-1999). Quaternary Science Reviews, in press.Rodbell, D. T. and Seltzer, G. O. (2000). Rapid Ice Margin Fluctuations during the Younger Dryas in the TropicalAndes. , 328-338.Quaternary Research 54

(Above): Mean annual solar radiation flux (Wm )verses average surface lowering (m) calculated forthe 3 Queshque glaciers, identified by name.

-2

(Left): Hypsometric curves forthe Queshque glaciers, showingarea with altitude. TheQueshque Main glacier hasmore mass exposed at lowerelevation.

(Left): Annual deviation oftemperature from the1961-1990 average from29 Peruvian stationslocated between 9-12 Slatitude, ranging inelevation from 20 - 4600 ma.s.l. The trends are basedon ordinary least squaresregression, and thevertical bars extend 2standard errors of themean on either side of theannual average.

(Left): Normalized anomaliesof annual precipitation totals(mm) from 45 Peruvianstations above 3000 m a.s.l.Between 1953-1998. Verticalbars extend 2 standard errorsof the mean on either side ofthe annual averaged anomaly.