PENINSULA

Kuwait

SURYEY PROBES/SIGNAL PAPER 560-F
Geology of the Arabian Peninsula

Kuwait

By D. I. MILTON

GEOLOGICAL SURVEY PROFESSIONAL PAPER 560-F

A review of the surface geology of Kuwait as 

shown on USGS Miscellaneous Geologic Investigations Map I-2?O A, "Geologic Map of the 

Arabian Peninsula" 1963

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1967
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 20 cents (paper cover)
FOREWORD

This volume, "The Geology oj the Arabian Peninsula" is a logical consequence of the 

geographic and geologic mapping project of ^he Arabian Peninsula, a cooperative venture 

between the Kingdom of Saudi Arabia and the Government of the United States. The ArabianAmerican Oil Co. and the U.S. Geological Survey did the fieldwork within the Kingdom of 

Saudi Arabia, and, with the approval of the governments of neighboring countries, a number of 

other oil companies contributed additional mapping to complete the coverage of the whole of 

the Arabian Peninsula. So far as we are aware, this is a unique experiment in geological 

cooperation among several governments, petroleum companies, and individuals.

The plan for a cooperative mapping project was originally conceived in July 1953 by the 

late William E. Wrather, then Director of the U.S. Geological Survey, the late James Terry 

Duce, then Vice President of Aramco, and the late E. L. deGolyer. George Wadsworth, then 

U.S. Ambassador to Saudi Arabia, and Sheikh Abdullah Sulaiman, then Minister of Finance 

of the Government of Saudi Arabia, lent their support to the plan. In November of the following year, 1954, Director Wrather approved the U.S. Geological Survey's participation and 

designated G. F. Brown responsible for the western Arabian shield region in which he had 

previously worked under U.S. foreign-aid programs. In January 1955 F. A. Davies, Chairman, 

Board of Directors, Arabian-American Oil Co., approved Aramco's participation and appointed 

the late R. A. Bramkamp, chief geologist, responsible for compilation of the area within the 

Kingdom where the sediments crop out. This responsibility fell to L. F. Ramirez following 

the death of R. A. Bramkamp in September 1958.

R. A. Bramkamp and G. F. Brown met in New York in February 1955 and planned the 

program, including scales of maps, areas of responsibility, types of terrain representation, 

and bilingual names. Thus there was established a cooperative agreement between the Kingdom of Saudi Arabia, the U.S. Department of State, and the Arabian-American Oil Co. to 

make available the basic areal geology as mapped by Aramco and the U.S. Geological Survey.

The agreement specified publication of a series of 21 maps on a scale of 1:500,000, each 

map covering an area 3° of longitude and 4° of latitude. Separate geologic and geographic 

versions were to be printed for each of the quadrangles; both versions were to be bilingual in 

Arabic and English. A peninsular geologic map on a scale of 1:2,000,000 was to conclude the 

project.

High-altitude photography, on a scale of 1:60,000, of the Kingdom of Saudi Arabia was 

initiated during 1949 by the Aero Service Corp. and completed in 1959. Both third-order 

vertical and horizontal control and shoran were utilized in compiling the photography. This 

controlled photography resulted in highly accurate geographic maps at the publication scale 

which then served as a base for the geologic overlay. The topography of the sedimentary 

areas was depicted by hachuring and that of the shield region by shaded relief utilizing the 

airbrush technique.

The first geographic quadrangle was published in July 1956 and the last in September 

1962. While preparation of the geographic sheets was in progress, a need arose for early 

publication of a l:2,000,000-scale peninsular geographic map. Consequently, a preliminary 

edition was compiled and published in both English and Arabic in 1958. The second edition, 

containing additional photography and considerable new topographic and cultural data, was 

published in 1963. The first of the geologic map series was published in July 1956 and the 

final sheet in early 1964. The cooperative map project was completed in October 1963 with 

the publication of the 1:2,000,000-scale "Geologic Map of the Arabian Peninsula" (Miscellaneous Geologic Investigations Map 1-270 A).

ni
IV FOREWORD

As work on the quadrangles progressed, geologists, companies, and governments working 

in areas adjacent to the Kingdom of Saudi Arabia were consulted by Aramco and invited 

to participate in the mapping project. The number of cooperating participants was expanded 

to 11, which included the operating oil companies in the peninsula and which are identified 

elsewhere in this text; the Overseas Geological Surveys, London; the Government of Jordan; 

F. Geukens, who had worked in Yemen; and Z. K. Beydoun, who had studied the Eastern 

Aden Protectorate. With the close cooperation of the authors, the new data were added to 

data already plotted on the base map of the Arabian Peninsula.

As the geological coverage of the peninsular map grew, the need for a text to accompany 

the map became apparent to both the U.S. Geological Survey and the Aramco geologists. 

Exploratory conversations were begun by Aramco with companies working in the other countries 

of the Arabian Peninsula for their participation in the preparation of a monograph on the 

geology of the Arabian Peninsula. Each author prepared a description of the geology of the 

area for which he was responsible, as shown in the sources of geologic compilation diagram" 

on the peninsular map. The U.S. Geological Survey undertook the publishing of the volume 

as a professional paper, and the Government of Saudi Arabia was to finance its printing. 

It was early agreed that there would be no effort to confine the contributions to a standard 

format and that no attempt would be made to work out an overall correlation chart other 

than shown on the "Geologic Map of the Arabian Peninsula." Thus, the individual style 

of authors of several nationalities is preserved.

Cooperation and relations have been of the highest order in all phases of the work. The 

project would not have been possible without the full support of the U.S. Department of State, 

the Kingdom of Saudi Arabia, and all contributors. In fact, the funds which made publication of this volume possible were contributed by the Saudi Arabian Government.

The data provided by the maps and in the professional paper provide information for 

an orderly scientific and economic development of a subcontinent.

O. A. SfcfGER,

Arabian-American Oil Co. (Retired).

W. D. Jfc^rfsTON, JR., \S 

Former Chief, Foreign Geology Branch,

£7.$. Geological Survey.
CONTENTS

Foreword--_-_-_____--_-____-_____-____-_____-_____

Abstract.__________________________________________

Introduction _______________________________________

History of exploration in Kuwait _________________

Acknowledgments ____________ __________________

Geography_ _______________________________________

Location and regional setting___________________

Topography_ _________________________________

Ground-water supplies.________________________

Geology ___________________________________________

Surface rocks___________________________________

Recent beds (Quaternary)___________________

Dibdibba Formation (Miocene to Pleistocene) __ 

Lower Fars Formation (lower to middle Miocene) ____________________________________

Page

in

Fl

1

1

3

3

3

3

4

5

5

5

5

Geology Continued

Surface rocks Continued

Ghar Formation (Oligocene and lower Miocene)_..__.._ 

Kuwait Group (Miocene, Pliocene, and Pleistocene) _ _____________--_----___-___----__

Subsurface rocks_______-____--__----_-----_---_-

Eocene formations. ____--___--__-__------__-

Cretaceous formations _ ____________________

Pre-Cretaceous formations ___________________

Structure______---_----_-_--_----------------------

Gas and oil seeps- -__-__--_____------_------_-------

Literature cited. _________-__________---_----_-_-_-_-

Page

F6

6

6

6

6

6

6

7

7

TABLE

TABLE 1. Exploratory wells in Kuwait, 1936-62, including structural and stratigraphic tests. --__-________-__-_______---_____----_------_------

Page

F3

GEOLOGY OF THE ARABIAN PENINSULA

KUWAIT

By D. I. MILTON x

ABSTRACT

Kuwait has a desert topography of low to moderate relief. 

Only in the Jal-Az-Zor escarpment can the relief be termed bold. 

Bocks ranging in age from early Miocene to Recent are exposed 

within the boundaries of Kuwait. Low dips and similarity of 

lithology make correlation of formations difficult. Maximum 

thicknesses of 3,200 feet of Eocene beds, 10,000 feet of Cretaceous 

beds, and 4,500 feet of Jurassic beds have been penetrated by the 

drill, and one well was drilled 427 feet into beds of Triassic 

age. Gentle folds are present within Kuwait, and apparently 

these folds, with the exception of those in eastern Kuwait arising from the Zagros orogeny, have been steadily growing since 

at least middle Cretaceous time. Oil and gas seeps are present 

at Bahra, bitumen at Burgan, and gas at Magwa. Relatively 

little potable water has been discovered within the State, but 

large volumes of brackish water are available.

INTRODUCTION 

HISTORY OP EXPLORATION IN KUWAIT

Interest in the oil possibilities of Kuwait began in 

1914 with the visit of S. L. James, who held a British 

Admiralty commission. He described the seepages at 

Bahra and Burgan and recommended that shallow wells 

be drilled to define any structures associated with these 

seeps. Additional investigations of Kuwait were made 

in 1917 by S. L. James and G. W. Halse; in 1926, by 

B. K. N. Wyllie and A. G. H. Mayhew; in 1931, by T. 

Dewhurst; and in 1931-32, by P. T. Cox.

Negotiations by American and British oil companies 

for a concession in Kuwait began in 1929. These negotiations were not successful until 1934 when after the 

formation of the Kuwait Oil Co., Ltd., a British corporation a concession was granted on December 23. 

The Kuwait Oil Co., Ltd., of which 50 percent is owned 

by the Gulf Oil Corp. and 50 percent by British Petroleum Co. Ltd., was granted exclusive rights to explore 

and produce oil in Kuwait by His Excellency Shaikh 

Ahmad Al Jabir Al Sabah, the late Euler of Kuwait. 

The concession was for 75 years and covered the whole

1 Of the Kuwait Oil Co., Ltd.

of Kuwait State, including all islands and territorial 

waters up to 6 nautical miles offshore from the lowwater mark.

In 1951, with the consent of His Excellency Shaikh 

Abdulla Al Sabah, Ruler of Kuwait, the rights and 

obligations under the concession were assigned by the 

Kuwait Oil Co., Ltd., to the owning companies the 

Gulf Kuwait Co., a wholly owned subsidiary of Gulf 

Oil Corp., and BP (Kuwait) Ltd., a wholly owned subsidiary of British Petroleum Co. Ltd. each being 

vested with an undivided half interest therein; the 

Kuwait Oil Co., Ltd., was appointed as a purely operating company to manage and carry on the work under 

the concession on behalf of the owners. In that same 

year the Concession Agreement was extended by 17 

years (and now expires in the year 2026), and the owning companies renounced all claims that the concession 

covered the islands of Kubar, Qaru, or Umm al 

Maradim.

In 1962, the owners relinquished their exploration 

rights to approximately half of the area covered by the 

original concession.

In the winter of 1931-32, two prospect holes were 

drilled by the Anglo-Persian Oil Co., Ltd. One was 

near Bahra on the north shore of Kuwait Bay and the 

other near the oil seeps at Burgan. Both of these holes 

were shallow and only partly penetrated the Miocene 

sands which occur at the surface. On March 16, 1935, 

after the Concession Agreement had been signed, a geological party composed of R. O. Rhoades and G. H. 

Growl of Gulf Oil Corp. arrived in Kuwait. They were 

accompanied by G. M. Shaw of Anglo-Iranian Oil Co., 

Ltd., and later P. T. Cox of the same company joined 

the party. A preliminary survey was made, and then 

Shaw and Cox returned to Iran on March 24. From the 

beginning of April to May 20,1935, Rhoades and Growl 

made detailed surveys in the vicinity of Bahra where oil 

and gas seeps are present, in the M'dairah district,

Fl
F2 GEOLOGY OF THE ARABIAN PENINSULA

and reexamined in more detail the Th'ar Ridge which 

is now called the Ahmadi Ridge. Cox returned to 

Kuwait from May 27 to June 3,1935, and in conjunction 

with Rhoades compiled a report covering these surveys. 

This report recommended that deep wells be drilled near 

the sites of the three seepages at Bahra, Burgan, and 

Madaniyat.

Evidence obtained during the geological surveys indicated a gentle anticline in the Miocene beds at Bahra 

(Fox, 1956). It was recommended that an exploratory 

well to test the Eocene and Cretaceous formations be 

drilled at the crest of this anticline. Bahra 1, which 

was the first wildcat well within Kuwait, was spudded 

on May 30, 1936.

It was hoped that a stratigraphic succession similar 

to that at Bahrain would be penetrated. Geological information from Bahra 1 showed that broad lithological 

similarities between this well and Bahrain were present 

although the individual formations had thickened considerably in the Bahra area. In April 1937, Bahra 1 

reached the total depth of 7,950 feet in sandstones of 

middle Cretaceous age. These sandstones can be correlated with the lower producing formation of Bahrain. 

No commercial accumulation of oil was found, although 

the Cenomanian limestones had slight shows of oil.

While Bahra 1 was being drilled, a geophysical survey 

of Kuwait was started by a party from Gulf Oil Corp. 

equipped to do gravity, magnetic, and seismic work. 

In the early part of the survey the gravity results were 

more promising than the magnetic results, so the magnetic survey was stopped and the personnel were added 

to the gravity party. The entire land area of Kuwait 

was surveyed by the gravity party in one working season, which was from September 1936 through May 1937.

Seismic operations wTere continued during this same 

season, and results of both gravity and seismic studies 

confirmed a structural area of interest south of Kuwait 

Bay in the vicinity of the Burgan oil seep. On the basis 

of the surface geology and subsequent seismic interpretations, the second exploratory well, Burgan 1, was located in this area. Drilling commenced on October 16, 

1937, and on February 23,1938, an oil-bearing formation 

was penetrated at 3,671 feet (driller's depth). After 

casing was cemented, the well was tested and oil flowed 

to the surface. Because of the lack of testing equipment 

in Kuwait, a definite production rate was not obtained. 

However, the well was tested in December 1938, and 

made 4,386 barrels per day on a 1-inch choke. In the 

period 1938-42 eight more wells were drilled on the 

Burgan structure, and a productive area of considerable 

size was outlined. Also during this time an exploratory 

well was started at Madaniyat. This well had reached 

a depth of 2,580 feet in the Upper Cretaceous when all

drilling was suspended in 1942, owing to the international situation.

In 1945 an extensive development program was initiated and the first cargo of Kuwait crude oil was 

shipped in June 1946, aboard the S.S. British Fusilier. 

Madaniyat 1 was not deepened when drilling operations 

were resumed.

Since 1945 various seismic surveys have been made, 

and at the present time the original concession area has 

been covered by reconnaissance reflection work. Areas 

of particular potential have been surveyed in much more 

detail. Structure-drilling programs have been carried 

out in a few selected areas, the most important of which 

is the Ahmadi Ridge.

While the above exploratory work was in progress, 

results indicated several areas of potential warranting 

investigation by the drill. When the development drilling program in the Burgan field had reached a point 

where equipment and personnel could be released, an 

exploration drilling program was started. The first 

effective exploratory well on this program was a deep 

test to investigate lower geological formations in the 

Burgan field. This well, now BG-113, was spudded 

on March 4, 1950, and reached its total depth of 13,853 

feet on July 25, 1951. At total depth BG-113 was in 

beds of Triassic (?) age, but no commercial shows of 

oil or gas were found below the Burgan Formation.

The next wildcat was sited to test a seismic structure 

lying about 15 miles north of the center of the Burgan 

field. This well, Magwa 1, was spudded on August 23, 

1951, and on October 4,1951, penetrated the uppermost 

oil-bearing sands of the Wara Formation. Magwa 1 

was drilled to 7,373 feet in the Ratawi Formation, but 

only slight oil shows were present below the Burgan 

sands. The well was completed as a producer from the 

Burgan Formation on January 30, 1952, and is the 

discovery well for the Magwa field.

During 1951 and 1952, seismic and structure-drilling 

results indicated that the Th'ar or Ahmadi Ridge was 

the surface expression of an anticline. On August 21, 

1952, Ahmadi 1 was spudded to test this structure. This 

well obtained commercial production from the Wara 

and Mauddud Formations and was completed at a total 

depth of 5,349 feet on December 14, 1952; it is the discovery well for the Ahmadi field.

Since 1952 exploration drilling has been extended to 

areas outside southeast Kuwait, where favorable structural conditions were indicated by seismic work. Oil 

accumulations have been found at Raudhatain, Sabriya, 

Minagish, Umm-Gudair, and Bahra 2 in the period 

1953-62. Data on exploratory drilling done by Kuwait 

Oil Co. within its concession are shown in table 1.

Table 1 shows that Kuwait Oil Co., to the end of 1962,
KUWAIT F3

drilled 18 new-field wildcats, of which 9 were discoveries, a discovery rate of 50 percent. Also two deeper 

pool tests were drilled. In one of these, RA-27, testing 

of the lower intervals is awaiting special equipment, and 

the other, BG-113, was effectively dry in the lower formations. At the end of 1962 four new-field wildcats 

were being drilled; all are on seismic structures.

ACKNOWLEDGMENTS

Owing to the paucity of outcrops most surface geological work was completed in Kuwait in the early years 

of the concession. Most of the information for this report has been taken from unpublished reports in the 

files of Kuwait Oil Co., particularly those reports prepared by P. T. Cox and R. O. Rhoades, 1935; J. D. 

Moody, 1947; I. E. Higginbottom, 1954; J. T. O'B. 

Perry and B. H. Al Refai, 1957; and D. I. Milton and 

C. C. S. Davies, 1961. The geologists who have contributed the greater part of the information on the surface geology of Kuwait are R. O. Rhoades of Gulf Oil 

Corp. (deceased), P. T. Cox of British Petroleum Co. 

(retired) and J. D. Moody, formerly with Kuwait Oil 

Co. The work of all Kuwait Oil Co. geologists, past 

and present, has been drawn upon and is gratefully 

acknowledged.

GEOGRAPHY 

LOCATION AND REGIONAL SETTING

The State of Kuwait, comprising an area of approximately 5,700 square miles, lies on the western shore at 

the head of the Persian Gulf (Arabian Gulf) in the 

northeastern part of the Arabian Peninsula. It is bordered on the north and west by Iraq and on the south 

by Saudi Arabia and the Neutral Zone, jointly controlled by Kuwait and Saudi Arabia.

TOPOGRAPHY

The ground surface of Kuwait rises gradually from 

the shores of the Persian Gulf (Arabian Gulf) toward 

the southwest in gentle undulations. Altitudes range 

from 0 feet in the eastern part to about 900 feet above 

sea level at the extreme southwestern corner of the 

State. Local relief is low except in the Jal-Az-Zor 

escarpment along the north shore of Kuwait Bay, the 

Ahmadi Ridge paralleling the east coast of Kuwait, 

the small hills at Wara and Burgan, and the Wadi al 

Batin along the western border. The relief can be 

called bold only in the Jal-Az-Zor escarpment.

The Jal-Az-Zor escarpment, about 50 miles in length, 

is the most prominent topographic feature. Local reTABLE 1. Exploratory wells in Kuwait, 1936- 62, including structural and stratigraphic tests

Well name

Bahral. ........

Madam yat I...,.

Burgan 113.-- _

Magwa 1. .. _ ..

Umm Gudair 1 

Raudhatain 1 _

Bahra 2. _,_-__ 

Sabriya 1. .......

Magwa 41--- ....

Mutribal 

Minagish I---...

Dibdibba I.. ,.

Mutriba 2- _ . - ..

Mityaha 1-.-- ...

Mityaha 2. ......

Mityaha 3 __ . 

Raudhatain 28 

Burgan274..- _

Dibdibba 2. ..

Minagish 5_ ___

Dibdibba 3.- 

Umm Oudair 2. .

Umm Gudair 3 

Raudhatain 27- ..

Bahra 3 ------ _

Medina l-_ __ ..

Bubiyan 1- __ .. 

Khashman 1 __

Classification

New-field

wildcat, 

. .do ......

 do ......

Deeper pool

test.

wildcat, 

 do 

... ..do ......

 do 

... ..do ..... -

- do ... ...

 -.do- ... .

 do... ......

 -do .

..... do... ...

- do .....

Structure

hole, 

. .do -...

. do... ......

New-field

wildcat. 

... ..do ... ...

Structure

hole. 

New-field

wildcat. 

Structure

hole. 

New-field

wildcat, 

- do- ..-.

Deeper pool

test. 

New-field

wildcat, 

 do 

... -.do ..... 

 .do .....

Locating method

seismic. 

 ..do ... ......

drill. 

 do ... ..

 do .... ... -

 do . - ...

 do 

 -do -. .....

 do .... ....

. do 

 -do ....... -

... . .do ... 

 do 

 ..do ..... ... 

 -.do .... ....

 -do ....... ...

- do .........

 -do ...

 -do ... ......

.. do..... ........

- do .........

Seismic

subsurface.

 .do .. ..... ...

 . .do .... ..... 

... ..do. .... .....

Spud date

May 30, 1936

Oct. 16,1937

Aug. 23,1951

A ncr 91 1Q^9

Feb. 14,1954

CJorrf- 19 iQ'vt

July 4, 1956

Aug. 11,1956

May 24, 1957

Oct. 4, 1958

July 27,1959

QoT-if O IQfifl

Or»f 9fi IQfifi

Jan. 7, 1961

Mar. 27, 1961 

May 11 1961

Aug. 26,1961

Nov. 9,1961

T\pp O IQfil

Mar. 19, 1962

May 24, 1962

June 15,1962

Sept. 9,1962

Nov. 26,1962 

Dec. 4, 1962

Completion 

date

Apr. 14,1937

May 14,1938

Tnlv 1^? 1049

July 31,1951

Dec. 14,1952

A tier ft 1 Q*U.

Nov. 28, 1955

May 7, 1957

Nov. 28, 1959

Aug. 26,1959

Oct. 11,1959

Apr. 1, 1962

Jan. 4, 1961

Mar 24 1961

Aug. 8, 1961 

Aug. 1, 1961

Oct. 30,1961

Mar. 11, 1962

T?nV» 95 1Qfi9

May 18 1962

Aug. 3,1962

Nov. 23, 1962

..... do..... ...

 do 

 .do ...

Total 

depth 

(feet)

7 Q'VI

3 692

2

CQA

 1O QCO

7 **7^

5,349

8,017

10, 301

8,488

10,200

S

ojn

11, 516

9 438

15, 610

8

noo

7 Qfi7

8,618

9 4.7C

5,635

8

CKA

19 R*wl

8 Q7ft

9,275

9

04.K

12,983

..........

Deepest formation or 

rock age

Warn

TYiaccip c>\

..... do ... ...

Hith.... ...

.... -do- ....

Shuaiba. .... .. 

 -do 

..... do 

..... do ......

Hith 

 -do 

 .do .... . 

..... do: 

Pay zone

Wara.-. 

\Vsrs~lVt fliiclclucl

Zubair.

 -.do -

 do. 

 -do 

 -do 

 ..do 

 do 

... -.do .... .... -

 ..do -

 -do ... ...

 .. do ... .... 

..... do. ... -

Testing not

completed.

i ::::. - 

Remarks

Suspended drilling owing to war.

Pre-Burgan formations dry.

Discovery well Magwa field.

taceous limestone. No production.

completed in Zubair.

shows also in Burgan.

Drilled for velocity and stratigraphic

information. 

Do.

Do.

Drilled for velocity and stratigraphic

information. 

Discovery well west Umm Gudair.

Originally drilled to 10,320 as a

Zubair development well.
F4 GEOLOGY OF THE ARABIAN PENINSULA

lief reaches about 400 feet at al Mutla near the southwest end of Kuwait Bay. The escarpment has a remarkably straight course in a N. 40° E. direction from 

al Atraf to about the center of the north shore of Kuwait 

Bay. In the area of Bahra 1 the Jal-Az-Zor swings 

northward in a gentle arc through east to a southeast 

direction. This new trend is maintained to the end of 

the escarpment near Subiyah at the northeast corner 

of the bay. The base of the scarp is covered by loose 

sediment which slopes uniformly toward the bay, and 

only the upper 100 to 150 feet has bold relief. Behind 

the escarpment the surface slopes gently away from 

the edge into a broad, shallow depression.

In southeastern Kuwait the hills at Wara and 

Burgan and to a lesser degree at Gurain and Madaniyat 

show relatively bold relief. The Wara hill is the most 

striking and has local relief of about 100 feet. The 

Burgan hills are roughly circular in shape and stand 

about 150 feet above the surrounding plain. The hills 

at Madaniyat and Gurain are much lower and more 

rounded in form.

The Ahmadi Eidge parallels the coastline south of 

Kuwait city and rises to heights of 385 feet above sea 

level. The crest of the ridge is about 5 miles inland, 

and both east and west slopes are very gentle, few 

mappable beds being traceable over any distance.

The Wadi al Batin, where it forms the western border 

of Kuwait, has an average width of 5 to 7 miles and 

relief as great as 200 feet. The greater part of its 

course has a direction of N. 35° E. Only the upper 

parts of the side slopes are being scoured by drainage, 

and in the extreme southwestern part of Kuwait, a few 

ravines have steep walls 15 to 20 feet high. In these a 

few hard beds can be traced for short distances. The 

bottom of the Wadi al Batin is being aggraded.

In the northern and western parts of Kuwait the surface is covered by widespread gravel plains. Parallel 

gravel-capped ridges trend northeastward; although 

only a few feet in altitude above the general level of the 

surface, they are very conspicuous and characteristic 

features of this area. These ridges are barren of vegetation, but there is some vegetation in the sandy depressions separating them.

Apart from the hills and ridges mentioned earlier, 

the southeastern quarter of Kuwait is low lying and generally flat. Very little gravel occurs at the surface, 

which is mainly composed of windblown sand. Numerous mudflats (sabkhat) are present in low-lying areas 

where inland drainage basins are present.

The northeastern part of Kuwait includes low-lying 

muddy shores and several offshore islands, the largest 

of which is Bubiyan. This area is believed to be the 

site of deltaic and estuarine deposition by the TigrisEuphrates River system. None of the islands, which 

at the surface are mainly silt and clay with some windblown sand, rise above 10 feet in altitude. Surrounding 

these islands are areas of extensive mudflats.

GROUND-WATER SUPPLIES

Historically, Kuwait is well known for several important watering places which are used by Bedouins in 

their travels through the northeastern part of the 

Arabian Peninsula. These oases, at Jahra, Subahiya, 

and Tawil, obtain water at shallow depth in the surface 

sands. The water supplies are virtually permanent 

although there is a gradual deterioration in water 

quality late in the year before the replenishing rains 

fall.

The Kuwait Oil Co. and the State Government have 

carried out extensive water exploration programs since 

1946. These programs have delineated the extent and 

potential of major ground-water supplies within the 

State of Kuwait. These accumulations are of three 

types and are present in three separate and distinct 

aquifers.

Where the topography is such that topographic highs 

form concentrating drainage surfaces, some rainwater 

collects in the surface sands at depths less than 20 feet. 

These accumulations are of very limited extent, and the 

water quality has usually deteriorated so much by the 

end of the summer that it is barely usable by humans. 

Also percolation through the surface sands, which contain a high proportion of gypsum and gypsiferous clays, 

usually results in a high sulf ate content.

In 1960, a well drilled in north Kuwait by the State 

found an accumulation of potable water in the Dibdibba 

Formation at approximately 100 feet. This well was 

drilled in a topographic low to the west of the Raudhatain oil field where the Raudhatain anticline has 

reversed the regional dip. In 1961, reserves of 100 billion gallons were estimated for this reservoir. The 

water is now being delivered to Kuwait city for inclusion in the State water system.

Additional exploration has revealed other fresh-water 

accumulations in north Kuwait where subsurface conditions are similar to those at Raudhatain. To the west 

of the Sabriya oil field a water accumulation is being 

developed for the State water system, although the 

water is of poorer quality than that at Raudhatain. 

Elsewhere in north Kuwait small accumulations of 

fresh water have been found, but none are of sufficientvolume to warrant extensive development.

The Dammam Limestone, which is volumetrically 

the most important aquifer in Kuwait, occurs at depths 

ranging from the surface near Ahmadi to 1,200 feet in 

northeastern Kuwait. The formation dips at about 9
KUWAIT F5

feet per mile from southwest to northeast except where 

interrupted by post-Eocene structures. Throughout 

Kuwait numerous water wells have been drilled to this 

formation, and its potential as an aquifer is reasonably 

well known. The static fluid level falls at approximately 

4 feet per mile from southwest to northeast, and the 

total-dissolved-solids content increases in this same 

direction.

The southwestern quarter of Kuwait contains water 

of usable quality, having less than 5,000 ppm (parts per 

million) total dissolved solids; the best water in that 

quarter is at the extreme southwestern corner and has 

2,281 ppm total dissolved solids. Away from this area 

the water in the Dammam rapidly becomes very saline. 

The Dammam water is used for irrigation and industry 

and is added to distilled water for human consumption.

All water in formations below the Dammam is extremely saline and is not usable without treatment.

GEOLOGY 

SURFACE BOCKS

Rocks ranging in age from early Miocene to Kecent 

are exposed on the surface throughout the State of 

Kuwait. The very low dips and similarity of lithology 

make correlation of formations difficult, as marker beds 

can be traced accurately for only short distances. Along 

the Jal-Az-Zor escarpment three formations can be recognized, owing to the presence of fossiliferous clays of 

the Lower Fars Formation which separate the overlying Dibdibba Formation from the Ghar Formation. 

Where the Lower Fars cannot be recognized, no subdivision is possible, and the entire sequence is called the 

Kuwait Group.

Detailed descriptions of the formations follow.

RECENT BEDS (QUATERNARY)

Kecent deposits within Kuwait consist of the following types:

Beach deposits are composed of reworked sandstone 

from the Kuwait Group; these sands may be cemented 

with calcium carbonate and are current bedded. Some 

oolitic limestones and shelly limestones also occur. The 

fossils within these beds have been correlated with 

present species.

Extensive deltaic and tidal mudflats are found in 

northeastern Kuwait, Bubiyan Island, and along the 

north shore of Kuwait Bay. These are composed predominantly of plastic clay and silt having a high saline 

content. The material is considered by the author and 

others to have been deposited by the Tigris-Euphrates 

Kiver system.

Deposits formed in inland drainage basins are usually 

very fine silt and clay with a variable percentage of sand 

and a very high salt content.

Windblown sand is common.

DIBDIBBA FORMATION (MIOCENE TO PLEISTOCENE)

The Dibdibba Formation in Kuwait consists of all 

beds above the f ossilif erous horizons of the Lower Fars 

Formation except for Recent deposits. The formation 

is composed of sands and gravels with minor clay and 

gypsiferous sandy clay beds. The beds show poor to 

medium stratification and in places the sands are 

cemented by calcium carbonate and gypsum. The upper 

part of the formation consists of coarse gravels deposited in sheets and trains. These gravels are 

composed of metamorphic and igneous rock debris. J. 

D. Moody (unpub. data, 1947) has recognized two distinct groups of pebbles on the basis of shape analysis. 

One group has a high average roundness whereas the 

other has medium to low average roundness. The first 

group is composed of quartz and metamorphic rocks 

with lesser amounts of silicic igneous rocks and is considered by Moody to have been derived from Najd and 

the Hijaz. The second group is composed of various 

types of silicic and mafic volcanic rocks and is thought 

by Moody to have been derived from the lava flows of 

the Syrian Desert and northern Arabia.

These gravels differ widely in size, but a general increase in average size is noticeable toward the west. In 

ravines along the east side of the Wadi al Batin, elliptical boulders, as much as 2 feet in length along the major 

axis, have been found.

No diagnostic fossils have been found in the Dibdibba Formation. In that the Dibdibba grades downward into the Lower Fars Formation of Miocene age, 

the lower part might be at least this old. If the volcanic 

rocks found in the gravels in the upper part of the formation are derived from the lava flows of northern 

Arabia, which are reported to be of Pliocene and Pleistocene age, these gravels could not have been deposited 

before the late Pleistocene. For these reasons the Dibdibba Formation is believed to range in age from 

Miocene through Pleistocene.

LOWER FARS FORMATION (LOWER TO MIDDLE 

MIOCENE)

The only outcrop that is definitely Lower Fars Formation occurs in the Jal-Az-Zor escarpment in the 

Bahrah area as a 125-foot unit and is comparatively 

distinct from the formations above and below. The 

lithology as described by Cox and Rhoades (unpub. 

data, 1935) consists of alternating red and yellow sand-
F6 GEOLOGY OF THE ARABIAN PENINSULA

stones, red and green clays, and various intermediate 

clayey sandstones and silty clays.

Fossils are moderately common, but individual fossil 

beds cannot be traced laterally for more than 1 or 2 

miles. The most persistent fossil is a small lamellibranch which, according to Cox and Rhoades, is similar 

to the Clausinellas of the Lower and Middle Fars beds 

of Iran. The lamellibranch is found alone or associated with Ostrea vestita, Ostrea latimarginata, Dendritina cf. D. rangii, Turritella sp., Lucina sp., and Balanus 

sp. The presence of the above species and lateral correlation with the Lower Fars of Iran places the Lower 

Fars of Kuwait in the lower to middle Miocene.

GHAR FORMATION (OI.IGOCENE AN1> LOWER 

MIOCENE)

At the foot of the Jal-Az-Zor escarpment the Ghar 

Formation can be definitely identified owing to the 

presence of the overlying Lower Fars. In the vicinity of 

Bahrah approximately 100 feet of section is exposed. 

The lithology consists of current-bedded coarse-grained 

to pebbly sandstones which show a nodular sugaryweathering surface. Some of the sandstones are firmly 

cemented and calcareous, and a few green clay beds are 

scattered through the section. Information from the 

Kuwait Oil Co.'s Bahra 1 well shows that the Ghar is 

800 feet thick in this area and that it directly overlies the 

Dammam Formation of Eocene age.

No fossils have been identified in the section, but from 

stratigraphic considerations alone, Owen and Nasr 

(1958) have assigned the Ghar Formation to the 

Oligocene and lower Miocene.

KUWAIT GROUP (MIOCENE, FXJOCENE, AND 

PLEISTOCENE)

South of Kuwait Bay where the Lower Fars is absent, 

no subdivision of the beds above the Dammam Formation can be made, so they are simply called the Kuwait 

Group. Outcrops in southeast Kuwait consist chiefly 

of gray to yellow clayey sandstones with some pebbly 

sandstones. No more than 30 feet of continuous section 

is exposed at any one place and consequently lateral 

correlations are not possible.

In this area, at Wara and Burgan, there are hills 

which are capped by hard brown-weathering siliceous 

sandstone and chert. At Gurain hill, which is near 

the Kuwait boundary with the Neutral Zone, a thin 

bed of hard white cherty limestone approximately 2 

feet thick occurs at the top. According to Cox and 

Rhoades (unpub. data, 1935), this limestone is due to 

chemical precipitation, and its exact position in the 

sequence is doubtful.

SUBSURFACE ROCKS

A brief description of the lithology of the subsurface 

formations which have been penetrated by drilling is as 

follows.

EOCENE FORMATIONS

The formations identified as being of Eocene age 

range in thickness from 2,500 feet in southeast Kuwait 

to 3.200 feet in west Kuwait and range in age from Paleocene to middle Eocene. The sequence is composed predominantly of limestone except for an evaporite 

sequence (Rus Formation) of middle Eocene age. The 

contact with the Cretaceous is conformable.

CRETACEOUS FORMATIONS

The Cretaceous ranges in thickness from 6,000 feet in 

southeast Kuwait to 10,000 feet in northwest Kuwait. 

The lithology consists predominantly of limestone and 

subordinate shale and two major sandstone formations 

which are present in the Lower and middle Cretaceous. 

These are the Zubair Formation of Early Cretaceous age 

which is approximately 1,300 feet thick, and the Burgan 

Formation of middle Cretaceous age which is approximately 1,100 feet thick.

PRE-CRETACEOUS FORMATION'S

Although the top of the Jurassic has not been accurately determined, it is at present (1964) chosen as 

the top of the first anhydrite bed below rocks of Early 

Cretaceous age. This anhydrite is believed to be equivalent to the Hith Anhydrite of Saudi Arabia. Very 

little information is available about formations older 

than Cretaceous, as only two wells in Kuwait have 

penetrated formations below the Hith Anhydrite. A 

deep test in the Burgan field was drilled to 13,853 feet 

and at this depth was in rocks believed to be of Triassic 

age. At present, 4,500 feet of rock in this well is believed to be of Jurassic age. Of this 4,500 feet, the 

uppermost 1,500-foot section is evaporite beds and the 

remaining 3,000-foot section is limestone and some 

marl, shale, and thin anhydrite. The beds assigned to 

the Triassic consist of 627 feet of clay, marl, shale, and 

sandstone. Mutriba 2 in northwest Kuwait was drilled 

1,715 feet below the Hith Formation. The upper 1,610 

feet is evaporite beds and the lower 105 feet is dense 

limestone.

STRUCTURE

Regionally, Kuwait lies at the edge of the Arabian 

foreland on the southwest flank of the Persian Gulf geosyncline. The regional dip is to the northeast at about 

9 feet per mile. This regular-dip surface is interrupted 

by the Kuwait arch and by other major structures,
KUWAIT F7

which are present at Raudhatain, Umm Gudair, and 

Minagish. These structures are very gentle and no dips 

over 3° have been identified. Subsurface information 

indicates that these structures have been growing almost 

steadily since at least middle Cretaceous times, and possibly they are as old as Late Jurassic. The evidence indicates that the growth of the structures is the result of 

vertical movement rather than horizontal compression, 

especially in pre-Miocene times, but the exact cause of 

this movement has not been determined. The exception 

to the above is the Ahmadi structure, which appears to 

be the result of horizontal compression in post-Eocene 

times and is probably related to the Zagros orogeny.

GAS AND OIL SEEPS

At Bahra a seepage of thick tarry oil occurs and a gas 

seep is also present in the area. Subsurface data have 

shown that this oil is coming from the Lower Fars or

upper Ghar and is present in north Kuwait where structural features occur in the Miocene beds.

At Burgan a bitumen seep is present in the center of 

the oil field. Subsurface information shows that the oil 

comes from the underlying Eocene formations, which 

are saturated with tar and heavy oil. Faults have probably been the means by which this Eocene oil reached 

the surface and weathered to bitumen.

The gas seeps at Magwa are also above Eocene gas 

and tar accumulations and are probably due to faulting.

LITERATURE CITED

Fox, A. F., 1956, Oil occurrences in Kuwait: Internat. Geol.

Gong., 20th, Mexico, 1956, Symposium sobre Yacimientos de

Petr61eo y Gas, v. 2, p. 131-158. 

Owen, R. M. S., and Nasr, Sami N., 1958, Stratigraphy of the

Kuwait-Basra area, in Weeks, L. G., ed., Habitat of oil

>* * * a symposium: Tulsa, Okla., Am. Assoc. Petroleum

Geologists, p. 1252-1278.

U.S. GOVERNMENT PRINTING OFFICE: 1967 O 238-237