jornada.nmsu.edu · soil as substrate—chemical and physical properties. 2. landscape...

100
Dept. Plant & Environmental Sciences New Mexico State University

Upload: others

Post on 28-May-2020

1 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Dept. Plant & Environmental Sciences New Mexico State University

Page 2: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

1.  Soil as substrate—chemical and physical properties. 2.  Landscape connections—cross-scale feedbacks. 3.  Soil memory—legacy effects.

Page 3: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

1.  Soil as substrate—chemical and physical properties. 2.  Landscape connections—cross-scale feedbacks 3.  Soil memory—legacy effects.

Page 4: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

DESERT PROJECT

Page 5: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Mountains & Hills

Piedmont Slope (Bajada)

Basin Floor

Mountains & Hills

Rio Grande Valley

Basin Floors

Mountains

& Hills

Jornada Exp. Range Headquarters

New Mexico State Univ.

Gile et al. 1981

alluvial fill

Page 6: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

SSSA Proc. 1966

Page 7: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

NRCS SOIL CHARACTERIZATION DATA BASE

Page 8: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

NRCS SOIL CHARACTERIZATION DATA BASE

Page 9: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

See papers by Duniway et al., Hennessy et al., Herbel et al.

Page 10: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

1.  Soil as substrate—chemical and physical properties. 2.  Landscape connections—cross-scale feedbacks 3.  Soil memory—legacy effects.

Page 11: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 12: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 13: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

rhyolite alluvium

Page 14: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

gypsiferous clay

Page 15: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

quartzose eolian sand

Page 16: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 17: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 18: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

broad scale erosion

Page 19: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 20: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

fine scale erosion

Page 21: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 22: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 23: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 24: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 25: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 26: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 27: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 28: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

ORGAN PEAK

Page 29: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 30: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

SOUTH- FACING (7000 ft)

NORTH- FACING (7000 ft)

ORGAN PEAk 9000 ft

Page 31: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

SOUTH- FACING

Page 32: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

SOUTH- FACING

NORTH- FACING

Page 33: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

ORGAN PEAK

Page 34: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Nov 2010

Oct 2011

ORGAN PEAK (5 cm) deg F

Page 35: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Nov 2010

Oct 2011

ORGAN PEAK, NORTH FACING

(5 cm) deg F

Page 36: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Nov 2010

Oct 2011

NORTH FACING (5 cm) deg F

Page 37: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

ORGAN PEAK

April 2011

Page 38: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 39: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

SOUTH FACING, NORTH FACING

(5 cm) deg F

Nov 2010

Oct 2011

Page 40: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

SOUTH FACING (5 cm) deg F

Nov 2010

Oct 2011

Page 41: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

ORGAN MTNS TEMPERATURE (ALL SITES) 5 cm

deg F

Nov 2010

Oct 2011

Page 42: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 43: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

C Cali G Summ

C Sand

G Basn

P Coll

NPP Sites

Page 44: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 45: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 46: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 47: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Stellar (Ustic Calciargid)

Annual precipitation =

After Herbel et al. (1994)

Page 48: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Stellar (Ustic Calciargid)

Stellar (Ustic Calciargid). Run-in water excluded by metal border

Annual precipitation =

Annual precipitation =

Page 49: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 50: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 51: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 52: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 53: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 54: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 55: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

wind

Page 56: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Texas

Page 57: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Kansas

Okalahoma

Texas

New Mexico New

Mexico

Texas

Okalahoma

Page 58: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Abiotic + Biotic

Page 59: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Abiotic + Biotic

Page 60: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 61: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Abiotic + Biotic

Page 62: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Abiotic + Biotic

Page 63: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Abiotic + Biotic

Page 64: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Abiotic + Biotic

Page 65: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Over Grazing

Page 66: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Over Grazing

Page 67: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

1.  Soil as substrate—chemical and physical properties. 2.  Landscape connections—cross-scale feedbacks 3.  Soil memory—legacy effects.

Page 68: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Soil profiles reflect bioclimatic regions

Page 69: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Soil profiles reflect bioclimatic regions

Page 70: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

My memory is like scratching steel— hard to do, but once done, the scratch

remains for a long time.

—Abraham Lincoln

Page 71: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

From Morrison ed. (1994); Imbrie et al. (1984)

GLACIAL-INTERGLACIAL CYCLES

How sensitive? How durable?

Page 72: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

From Morrison ed. (1994); Imbrie et al. (1984)

Hot-dry interglacial periods

Cool-moist glacial periods 20,000 yrs ago

Page 73: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Las Cruces

VIEW FROM INTERNATIONAL SPACE STATION

Lake Estancia

Lake Otero

San Agustin

Glacial-Pluvial Lakes

Allen 2005

Page 74: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Lake Palomas

Columbus Las Cruces

Page 75: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Columbus, NM

NASA World Wind Image

Page 76: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Torreon

Page 77: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 78: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

PIPE

resistant

Page 79: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

PIPE

Soil Memory “Pedokarst”

ca. 20 ka

resistant

Page 80: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

How sensitive? How durable?

years AD after Lamb 1977, Broecker 2001

Page 81: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

H.C. Monger

sensitive Carbon isotopic memory of C4 photosynthesis

Page 82: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

H.C. Monger

sensitive Carbon isotopic memory of C4 photosynthesis

Page 83: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

NMSU

Las Cruces

North

Hwy 70

NASA World Wind Landsat 7 pseudocolor

Carbon isotopic memory of C4 photosynthesis

Page 84: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

NASA World Wind Landsat 7 pseudocolor

Carbon isotopic memory of C4 photosynthesis

Page 85: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

NASA World Wind USGS 1m digital ortho

Carbon isotopic memory of C4 photosynthesis

Page 86: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

NASA World Wind USGS 1m digital ortho

Carbon isotopic memory of C4 photosynthesis

Page 87: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

NASA World Wind USGS 1m digital ortho

Carbon isotopic memory of C4 photosynthesis

Page 88: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Google Earth Image

Carbon isotopic memory of C4 photosynthesis

Page 89: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Carbon isotopic memory of C4 photosynthesis

Page 90: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Carbon isotopic memory of C4 photosynthesis

Page 91: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 92: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

grass dune bare ground

Page 93: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Btk horizon

K horizon

A horizon

Page 94: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower
Page 95: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

C4 grass C3 shrubs on dune bare

ground

-16.6 permil (81% C4)

-14.0 permil (100% C4)

-16.1 permil (76% C4)

-17.6 permil (67% C4)

Weems and Monger (2012) Ecosphere

Page 96: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

SOIL MEMORY—A TOOL FOR UNDERSTANDING AN EXPANDING ARIDOSPHERE

Page 97: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

1.  Soil as substrate—chemical and physical properties. 2.  Landscape connections—cross-scale feedbacks 3.  Soil memory—legacy effects.

Page 98: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

High Overprinting

Page 99: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

High Overprinting Lower Overprinting

Page 100: jornada.nmsu.edu · Soil as substrate—chemical and physical properties. 2. Landscape connections—cross-scale feedbacks 3. Soil memory—legacy effects. High Overprinting . Lower

Jornada I surface (ca. 600,000 years)

Jornada I surface (ca. 120,000 years)