Application of luminescence dating in Understanding

fluvial landscape of Himalaya

Pradeep Srivastava

Wadia Institute of Himalayan Geology

Dehradun, INDIA

Future Floods: an exploration of a cross disciplinary approach to flood risk forecasting

NUS, Singapore

Structure of the Talk

Some Fundamentals of Luminescence dating

Geology of Himalaya

Fluvial landscape of Himalaya: Climate and Tectonics

Conclusion

Photo: Ladakh Himalaya

Luminescence Dating: basic premise

Trapped electrons in a crystal increases due to ionizing radiation

Luminescence chronology: problems

1. low photon intensity

2. feldspar contamination

3. inhomogeneous bleaching

2. 40-60 aliquots of 7 mm size are used

3. Least 20 % of the palaeodoses with recycle ratio of

10% were used for final age estimation

4. Feldspar separates of few samples from NE Himalaya

were subjected to Elevated temperature Post IR-IR

protocol.

LD-95

0 20 40 60 80

20

40

60

80

100

Lu

min

escen

ce i

nte

nsi

ty (

x1

00)

Paleodose (Gy)

R = 0.04422

LD-96

0

0

25 50 75 100

20

40

60

80

100

Lu

min

escen

ce i

nte

nsi

ty (

x1

00)

Paleodose (Gy)

R = 0.56512

Problems & solution Geological Luminescence

Luminescence gained since last exposure

Aliquots

Ag

e

Dose (Gy)

2.0 3.0 4.0

Pro

b.

De

nsity

Dose distribution

A

B

Dose (Gy)

1,2001,0008006004002000

Pro

b.D

ens

ity

Precision (%)

0.080.060.040.020

Sta

ndard

ised

Estim

ate

20

-2

Equiv

ale

nt D

ose

Least age model

Precision (%)

0.0 4.0 8.0 12.0

-202

2.0

4.0

6.0

8.0

Equiv

ale

ntD

ose

Sta

nd

ard

ised

Estim

ate

Average age model

Preheat plateau

Dose recovery test

Preheat (°C)

Do

se r

ecove

ry r

atio

Dose recovery ratio

Recycling ratio

Recyclin

g ra

tio

Re

cu

pe

ratio

n ra

tio

Recuperation ratio

140 160 180 200 220 240 260 2800.8 0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.8

1.01.0

1.21.2

1.41.4

Science of Himalaya and Rivers

Himalaya provides a good look at c-c collisions

world's fastest uplift rate (10 mm/a at Nanga Parbat)

Himalaya acts as a barrier to cold Westerlies, defining the Indian

rainfall pattern

Provides insight into a natural Critical Taper Wedge

Provides insights into the evolution of world’s three major river

systems viz. The Brahmaputra, The Ganga, The

Indus…..supporting civilizations

Controlled the evolution of Ocean -Chemistry and -circulations.

Studies at several time scales

NW

Ind

ia C

ollid

es

End

of

Mari

ne S

edim

enta

tion

Cen

tral Tib

et ach

ieves

pre

sent heig

ht Story begins with the northward

movement of Indian Plate

India

Continued northward push lead to the shortening of Indian crust and

uplift of Himalaya

Courtesy: Irfan Ahmad, WIHG

Valdiya, 2001

N

~33 Ma

~23 Ma

Sinclair and Jaffey, 2001

Sedimentary profiles of Indus formation,

Ladakh indicate that in the beginning

there was a closed basin

Modern Indus at Nyoma

~23 Ma

Indicated by: palaeoflow

records of Indus formation

Longitudinal drainage

Closed basin

Paul et. al., 2007

Indus

12

6000 m

5000 m

4000 m

3000 m

2000 m

1000 m

125 km0

250 km 375 km 450 km 542 km

HFTMBT

MCT

STD KF

Indus R.

A B

CT

Su

ture

MCT

MBT

MCT

Ladakh Batholith

Higher

HimalayanCrystalline

Tethyan

HimalayaIndus

Group

Khardung

Volcanic Formation

100 km

0

10

20

40 Km

30

HFT

Himalaya: large scale structure & Climate

Chandigarh

Kirstin et al 2006

Present Configuration and rainfall distribution has

changed the deformation pattern of Himalaya

SW Monsoon Dominated Monsoon spill over during AMY

Winter Monsoon dominated zone

Significant S-N and E-W

gradient exists

Climate-vegetation vs.

erosion

Mountain front to MCT Zone

Lahul-Spiti valley

Trans Himalayan zone of Leh and Laddakh

Lesser Himalaya

Ganga Plain

Taper angle

Higher Siwaliks Himalaya

Taper angle represents balance between frictional

and gravitational forces

Super critical wedge

Minimum EROSION and continuous deformation lead to the

formation of a critical taper

What is Climate-Tectonic interaction in Himalaya ?

Increased

Rainfall &

erosion

Lesser Himalaya

Ganga Plain

Taper angle

Higher Siwaliks Himalaya

ACTIVE EROSION

Bookhagen and Burbank, 2006

There exist two

distinct high rainfall

belts in Himalaya

Least tectonic upliftment phase

Climate related aggradation

Slight tectonic upliftment and

aggradation

Intense tectonic upliftment giving lesser

time for river to aggrade

Archives in the river valleys…….

Srivastava and Misra, 2008

Starkel, 2003

Supana

Chauras

Kilkileshwar

A

A /

200 m

50 m

15 ka

Ray and Srivastava, 2010

Least tectonic uplift

Climate related aggradation

Terrace configuration

Sedimentology

Luminescence dating

Archives in the river valleys……. Intense tectonic uplift giving lesser

time for river to aggrade

Kumar and Srivastava, (in review)

Geological map of Bhagirathi-

Alaknanda Valley, NW Himalaya

(Ahmad et al., 2001).

Ray and Srivastava 2010

Digital Elevation Model (DEM) of

Bhagirathi-Alakhnanda Catchment

How NW Himalaya has been

evolving during the last ~50

ka

Longitudinal river profile of Alaknanda River

Ray and Srivastava, 2010; 2011

Ray and Srivastava, 2010; 2011

Aggradation: 37-11 ka

Ray and Srivastava, 2010; 2011

Choudhary et al., 2015

Ray and Srivastava, 2010

Chandi Devi (Haridwar)

Dutta et al., 2012

Tri

shu

liB

ak

eya

Bagm

ati A

ru

n

Tee

sta K

am

en

g

Bra

hm

ap

utr

a

Bhagirathi

Yamuna

Alaknanda

~15 ka

150 m

100 m

15 m

Arun River (LH)

40 m

~9.1 ka

Arun River (HH) 150 m

9.2 (0.2) ka

20 m

50 m

Bagmati River (OH)

11.3 (1.3) ka

150 m

190 m

Teesta River

180 m 15 (2) ka

25 m

Bhagirathi River (LH)

50 m

11.5 (1.5) ka

Brahmaputra River (OH)

Lave, 1997; Lave and Avouac, 2000

Malay et al., 2007 Srivastava et al., 2009 (JQS)

Singh, 1996; Ray and Srivastava, 2010

Shukla, Srivastava, 2012

Ganga River @ Varanasi

Scenario in the Ganga Foreland

Rivers in Ganga Plain are incised

15-30 m thick cliff are present

along the banks of major rivers

~14 ka

Incision chronology of Ganga River in Foreland (Ages in ka)

Fan section Tandon et al., (in press)

Aggradation took place till ~7 ka

The incision of Ganga river <7 ka

Srivastava et al., 2003 (Palaeo-3)

0 500 1000 1500 2000 2500

400

300

200

100

0

Nagal

Amroha

Budaun

Kanpur Varanasi

13 (GP-14)

(GP-8)

12

(TL-8)

7

(NN-6) <12.3

Distance from the mountain front (km) Srivastava et al, 2003

Data from Srivastava et al., 2008, 2009a,b

Ray and Srivastava, 2010

Srivastava and Misra, 2009

S W I n d i a n M o n s o o n

c h a n g e i n r a i n f a l l % f o r S A s i a

Generalized Climate curve derived from various sources

NW Himalayan rivers

Ganga Plain Rivers

~13-11 ka

~7-6 ka

Our work on Indus, Spiti Rivers (Drier Himalaya)

indicates that aggradation continued at least till

~6 ka

Aggradation

Incision

Time lag of 3-4 thousand years

Conclusion-I

>45-11 ka; the rivers in

Lesser Himalayan zone were

aggrading, foreland basin

was also aggrading

~11 ka, widespread river

incision in Himalaya,

continued aggradation in

the foreland basin

~7 ka, incision propagated to

foreland basin

Response to Climate Change

Conclusion # 1

Roughly 3.8 x 10e8 Tons of

sediment was locked within

the trunk channels of

Bhagirathi-Alaknanda river

Bedrock incision rate: 2-5 mm/a

Bedrock incision rate: ~7.5 mm/a

In-Sequence Deformation

Out-of-Sequence Deformation

Alaknanda-Ganga responding to Himalayan Taper

Ray and Srivastava, 2010

Conclusion-II

Thank you

Team

Yogesh Ray

Shipra Chaudhary

Anil Kumar

J K Tripathy

YP Sundriyal

Funding

DST, New Delhi

MoES, New Delhi

• Tectonic Geomorphology

• Palaeohydrology

• Dune records

Indus Suture Zone Himalayan Hinterland Arid Himalaya

6000 m

5000 m

4000 m

3000 m

2000 m

1000 m

125 km0

250 km 375 km 450 km 542 km

HFTMBT

MCT

STD KF

Indus R.

A B

CT

Su

ture

Geology: Indus River (Landsat: P.145 R. 37; Sensor ETM+ 30 m)

•Suture Zone Tectonics: evidences from Indus River Geomorphology

•Responses of Past climatic changes

10 km

Seg. I

Seg. IV

175 m

Incision rate: 4.7 mm/a

Segment-II

Bedrock incision rates

2-5 mm/a

8 sections are studied

(Searle et al 1990)

Structural cross –section along

Zanskar River between Chilling to

Nimu.

The height of strath terraces plotted on

the longitudinal river profile clearly

shows three levels of terraces.