Geology Of Mussorie- Field Work

MUSSORIE

A TRIP TO THE QUEEN OF HILL

CONTENTS

1. Preamble

2. Acknowledgement

3. Introduction

4. Instruments/Gadgets used

5. Geology of Himalayas

6. Geology of Mussoorie

7. Traverses

8. Conclusion

9. Bibliography

PREAMBLE

“A journey of worth remembering, enlightenment, experiences and great knowledge.” – I guess these words sum up my feelings for this year’s field trip that I along with my batch mates undertook.It was full of fun and learning. This year our class went to Mussoorie, as part of our field trip. Duration of the trip was for 5 days including the day of arrival and leaving. Our main focus during the whole trip was to study the geology of the area and most importantly to apply and observe the theoretical knowledge regarding various geologic structures we studied in our 1^st semester. It was a real learning experience for me as I got to see and witness the affects of the real forces which work all around us and help to shape our planet.

The main motive of this trip was :-

To understand the geology of Mussoorie
To identify the location on the toposheet with the help of GPS(Global Positioning System).
To identify geomorphological features
To observe local faults, folds etc.
To study outcrops and interpret

GEOLOGY OF HIMALAYAS

Himalaya is the youngest mountain chain in the world. It extends over a length of more than 2400km. The mighty Himalayas owe its existence to continent-continent collision during the tertiary orogeny, closure of Tethys Ocean by collision of Indian plate with Euro-Asian plate. The Himalaya exposes an enormous thickness of rock sequences ranging in age from Proterozoic to Cenozoic. It can be divided into 4 primary lithotectonic belts which run parallel to each other. The belts are-

i. Tethys Himalaya.

ii. Higher Himalaya.

iii. Lesser Himalaya

iv. Sub Himalaya.

Subject of our interest here is lesser Himalayas. Number of faults and thrusts, e. g., Alaknanda Fault, North Almora Thrust, and Kirtinagar Fault etc. occur in Lesser Himalaya. As a result of thrust activity, the old mature topography of the Lesser Himalaya has been changed to a great extent. The Late Pleistocene-Holocene activity of these faults and thrusts gave rise to various peculiar geomorphic features along Himalayan River Valleys such as change in river course (fossil valleys), deep gorges with convex walls, uplifted, deformed, tilted and multileveled fluvial terraces, formation of palaeolakes and old landslides. Few segments of the Himalayan Rivers in the Lesser Himalaya are exceptionally wide though all the river valleys as a whole are quite narrow. At these wider segments of the valleys,considerable pile of fluvial sediments is locked in form of up to 6 levels of terraces. There is a unanimous opinion among the Himalayan Geologists that these different levels of the river terraces show different phases of the upliftments. The hypothesis developed is based on extensive field observations in Alaknanda River Valley, one of the major snow fed tributary of Ganges System in the Himalaya.

GEOLOGY OF MUSSOORIE

Mussoorie, Queen of Hills,is one the most beautiful hill station of India.

Mussoorie is located in the state of uttrakhand , India at the coordinates of Latitude-30°19’04” to 30°23’20’’N and Longitude 78°10’ to 78°18’11”E. It is at elevation variation of 1600-2200 meters.

Geology of Mussoorie mainly consists of the Krol Formation, above the Blaini formation. Mussoorie has mostly got the lithology of Quartzite rock mainly of yellowish to brown in color. The geology of Mussoorie is the Syncline.The MBT(main thrust boundary) is dividing the Doon Valley and the Lesser Himalayas. This is also supported by the fact of changing lithology from limestone to grey shales.

Few of the wonderful sedimentary structures can also be found in the content of Geology of Mussoorie, which includes the Ripple Marks. This ripple marks are mostly present in the Sandstones, which are mostly ferruginous in content. At a particular site we can find Ripple markes of different current directions. Also in Mussoorie Geology, we can find few amazing structures of Cross Beddings.People also can find pabbly quartzite ,deposits of phosphorite.

Major deposite in Massurroie Dolomatic limestone and dolomite followed by Shale(Banded shale,Black micaceous Shale) followed by quartzite(grilly to pbbly), followed Phosphrite(cherty) .

Above all, Mussoorie is a Antiform Sycline. This means that it was primitively an anticlinal structure, but the erosion of the adjacent slopes visualizes it as Syncline. That is why it is called Antiform Syncline.

THE ANTIFORM SYNCLINE OF MUSSOORIE:

· A convex upward fold is an antiform while a convex downward fold is a synform.

· Anticline and syncline are terms with stratigraphic significance.

· Antiformal syncline and synformal anticlines may exist in regions of complex, polyphase deformation.

INSTRUMENTS USED

1. Field diary - It is required for noting down the various details of the outcrop. It is necessary for keeping a record of the observations.

2. Brunton Compass

3. Clinometer- An inclinometer or clinometer is an instrument for measuring the angles of slope, depression or elevation of an object with respect to gravity. It measures both inclines (positive slope) and declines (negative slope).

4.Global Positioning System (GPS) - It i s a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the earth where there is an unobstructed line of sight to four or more GPS satellites. It was handy to find the location.

5.Hammer, Measuring Tape, Lense

TRAVERSES

DAY 1(11/12/15)

Location-In front of Youth Hostel

Forward bearing N80E Backward Bearing S250°W

Elevation: 2000 - 2100m

Lithology: The lithology was composed of Phosphorite ranging from yellow(narrow belt) to black in colour.

Exposure 1:

In front Youth Hostel

Deposite- charty and black Phosphorite.

Bedding are slightly inclined and dip towards 80° North –West.

Beds are slighty wrinkles that shows that the beds are pucker.

Strike-47°-227°(NE-SW)

Dip angle -137°(SE)

21°/S137°E/NE-SW

Exposure 1

DAY 2(12/12/15)

Location - ECOLOGY PARK (Dhanaulti)

GPS Location : 30.45°N78.25°E

Elevation : 2286m (7500 ft)

Dhanaulti is a hill station 24 km from the popular hill station of Mussoorie, and 29 km from Chamba, as it is situated between the two.

coordinates	30.45°N ,78.25°E
elevation	2286 metre
attitude	60°S 15°W/ NW-SE
lithology	Exposure of Black Shale.
Vegetation	– Deodar , Rhododendron and Oak
Observation	Outcrop of weathered shale, highly parted

We are currently in the lesser Himalayan region and these hills are said to be to be present from the Proterozoic era.

Location	100 meter above Youth hostel towards Mussoorie
Elevation	2105 m
Attitude	dipping towards NE
lithology	Cherty Phosphorite
Vegetation	oak, pine, deodar

OTHER OBSERVATION- Exposure of cherty Phosphorite was highly . weathered.

ECO-Park- It is the main attraction of Dhanaulti. There are two Eco-parks, "Amber" and "Dhara" about 200 m apart.

Exposure - 1

Strike : 173°-353°(NW-SE)

Dip angle : 263°(SW)

28°/S93°W/NW-SE

100 m away from Kaplani there is an intercalation of Black Shale is noticed in Dolomatic Limestone which is highly fractured and jointed.

Most of them bedding dip towards South-West.

Fig :- Intercalation of shale in limestone

Mark 2:-

Location - Towards Kaplani

Exposure – 2

50m away from exposure1 towards kaplani.

Strike: : 60°-240°(NE-SW)

Dip angle: 150°(SE)

Dip Amount: 40°

40°/S30°E/NE-SW

Exposure - 3

20 feet from previous exposure.

Inclined bedding planes. Beds are dipped in SW direction.

STRIKE- 115° -295° (NW-SE)

DIP ANGLE - 205° (SW)

45°/S25°W/NW-SE

Beds are of RED SANDSTONE which is highly colonized by biological species like mosses and algae. Also, ferrous leaching was observed. Two sets of joints and fracture are clearly seen. Due to iron leaching color of upper surface turned to blackish.

Exposure - 4

Location- 50 m from previous exposure

Strike : 175°-355°(SE-NW)

Dip angle: 265°(SE)

45°/S85°W/SE-NW

Mark 3 :- On Dhanaulti road, towards Kaplani

Location -300 m from mark 2

Elevation :7292 ft

Exposure - 6

We found a productive horizon in the context of finding a trace fossil. The bedding surface was undulated and impressions of biological activity were visible.It also represented remnants of ripple marks.The mega ripples were also present in the vicinity.On these ripples the striations called slickenside were also prominent. There is Domen basin ripple, these dome like structure because of interference of ripple .

There was biological activity found near the ripple marks observed.

Fig: mega ripple marks in kaplani

Readings of dip for-

Ripples : S30°W

Slickenside : S60°W

Mark 4 - Masrana

Location : 300 m from mark 3

Lithology : Phosphorite, Dolomitic limestone

fig:- Clevage AND SEEN IN BLACK SHALE AT MASRANA

Exposures at masrana

Position	Dip amount	Dip direction	Strike	lithology
1	45°	N65°W	N65°E-S65°W	BLACK SHALE
2	10°	N50°W	N25°E-S25°W	Dolomitic limestone
4	45°	N70°W	N30°E- S30°W	LIMESTONE

*These readings were taken at approx. 100-200m away from previous location

DAY 3(13/12/15)

Mark 1 - Dhobighat

Exposure-1

Location : 700 m from Youth hostel, towards Mussoorie

Ø Dolomitic limestone exposed near Dhobighat

Ø Affluent streams get water from sub-surface.They are all perennial.

Exposure-2

Location : Uphill of Dhobighat, 200 m from previous location

Ø Highly weathered chirty phosphorite (contains more phosphorite and chalcedony) is exposed.

Ø Beddings are dipping towards NE.

Mark 2- Near Woodstock school, 8km away from Mussoorie

Lithology : shale -Argillicious

Exposure-3

Strike: 35°-215°(NE-SW)

Dip angle: 125°SE

15°/E35°S/NE-SW

Mark 3 - Batagad

The place is about 25 km from the youth hostel. We are currently in the lesser Himalayan region and these hills are said to be to be present from the Proterozoic era.There is the evidences of syncline.

EXPOSURE - 5

Red sandstone.

Inclined bedding planes. Beds are dipped in SW direction.

Coordinates - N30 27'20.4” AND E78 08'16.5”

STRIKE- 110-290 (NW-SE)

DIP ANGLE - 200° (SW)

45°/S20°W/NW-SE

EXPOSURE – 6

MULE VALLEY

GPS Location - N30 27'20.4” AND E78 08'16.5”

STRIKE – 110°-290°(NW-SE)

DIP DIRECTION- N25°E

DIP AMOUNT – 46°

Lithology- Quartzite

Vegetation- Beds are of quartzite which is highly colonized by biological species like mosses and algae. Also, ferrous leaching was observed. Two sets of joints and fracture are clearly seen. Due to iron leaching color of upper surface turned to blackish.

MARK-4 (JABARKHET)

Location- At the distance of 50 km from Chamba

Elevation- 7023 ft.

Bearing- SW

Strike- NW-SE

Dip direction- S30W

Dip amount- 40°

Lithology- Pebbly quartzite

Observations- Many big boulders are present. One can observe prominent joint plane.

Fig :- Quartzite

Fig :- Boulder in Jabarkhet

*Moving from Batagad to Jabarkhet we go from NE limb to SW limb of the Mussoorie syncline because the dip direction of beds changes from NE-SW to SW-NE.

The trace of the syncline axis was evident because intense fracturing had taken place here.

This outcrop provided the evidence for Mussoorie antiform-syncline structure. The outcrop serves as the axis for the valley of antiform-syncline structure for Mussoorie.

DAY 4(14/12/15)

Location - Kempty Fall Road, Near JW Marriott Hotel, 10 km away

from Youth Hostel.

Elevation - 5466 ft.

GPS Location - N30⁰ 27′ 362″ AND E 78⁰ 7′ 413″

Lithology - Dolomitic limestone was persistent in almost all

exposures, Shale.

OBSERVATION

We find an exposure where almost vertical bedding has been observed. About 30 m from this exposure towards Kempty Fall, almost horizontal bedding planes are seen.

Fig- Steep to Vertical bedding planes of Dolomite and possible removal of Shale between two Dolomitic beds

High faulted dolomitic landforms are examined. Around 29m from the strike region, there is an alternative strike region.

Exposure-1

10 km away from Youth Hostel.

Strike-: 30 - 210 NE-SW

Dip Direction:- 120⁰N

Amount:- 85⁰

Lithology - Dolomitic limestone, shale

Observation- Weathering and erosion of Phosphatic Shale between two Dolomitic beds.

Exposure -2

30 m from previous exposure.

Strike-: 155 -235 (NW-SE)

Dip-Direction: - N65 E

Amount- 35

Lithology - Dolomitic limestones

Observation - Landslide prone area, inclined bedding planes.

landslide region

This anomalous data shows that this exposure might just a broken rock from top of structures. This mig1ht be the exact reason because we saw that this is a landslide prone area.

Landforms:

Landforms: From opposite roadside at a far distance towards North, glacial landforms were observed. We identified cirques, arêtes, horns, U-shaped valleys and hanging valleys related to erosional processes of glaciers in Himalayas.

Fig- Glacial Landforms observed from Sia Bend towards North

Location-200m before kempty falls, at the top

Lithology- That of phosphorite and shale, highly brittle

Observation- Brittle deformation zone.

Kempty Fall: A case study

Location- Kempty falls.

Elevation-1364.

GPS Location -78°2’E AND 30°29’N.

Lithology- Limestone.

Observation- The area is surrounded by high mountain ranges at an altitude of 4500ft. and dissolution/ solution landform created from carbonate rocks.

The scenic beauty of hills of Uttarakhand includes the Kempty Falls. This is located about 10-15 km away, towards North, from Mussoorie.

This is a dissolution/ solution landform created from carbonate rocks. Waterfall formation is based around the basic principle that there is a watercourse traversing over different layers of rock each with different rates of erosion. Over time, the softer rock gets eroded by the water, ultimately making the watercourse steeper. This steepening effect also accelerates erosion as the influence of gravity on the water increases the water's speed. Eventually, the watercourse steepens until it's either nearly vertical or completely vertical. At this point we have a waterfall.

Fig:- Kempty Falls

TRAVERSE TAKEN THROUGHOUT THE FIEDWORK

DATE	TRAVERSE	LITHOLOGY
11/12/2015	YOUTH HOSTEL	PHOSPHORITE AND LIMESTONE
11/12/2015	DHOBHIGHAT	PHOSPHORITE AND LIMESTONE
12/12/2015	DHOBHIGHAT UPPER REACHES	CHERT AND DOLOMITIC LIMESTONE
	DHANAULTI	SHALE
	MASRANA	DOLOMTIC LIMESTONE AND SHALE
	KAPLANI	SANDSTONE
13/12/2015	BATAGHAT	QUARTZITE AND RED SANDSTONE
13/12/2015	JABARKHET	PEBBLY QUARTZITE
14/12/2015	KEMPTY FALLS	DOLOMITIC LIMESTONE

CONCLUSION

A field geologist must see the method of “working on multiple hypothesis” but one should never let their temporary hypothesis become the ruling theory while the investigation is still going on, making him capable of seeing the contradictory facts.

This field trip taught us basic of field geology by providing us with ample exposure to field work. The study of outcrop in and around Mussoorie and interception of various geologic structures gave us elucidated idea of the real geology which is related to the wide variety of rocks along with wide ranging structures made up of those rocks.

Mussoorie is one of the best places for geological study. It consists of most of the ancient formation, formed at the time of Indian and Asian plate thrust. The interaction is thrust continues to grow deeper and deeper every year subjecting the Himalayas a lift of 1mm, every year.

It was an amazing experience and I received a great knowledge about the structures, geomorphic features, and processes etc. which have been of a great use till date and also will be helpful in the coming future.