The Burma Circle of the Geological Survey of India and their Contributions to the Geology of Myanmar

By THAN HTUN

(GEOSCIENCE MYANMAR)

 

EPISODE:16
V P Sondhi came from a respectable family of Jallundhur and was born on 10 March 1903. He had his early education in Jallundhur but joined the Prince of Whales College, Jammu for higher education. In 1925, he obtained his MSc degree from that College, then affiliated with Punjab University, and one of the earliest to start teaching geology in the country.

V P Sondhi (1903-1989), Source: GSI
He joined the Geological Survey of India on November 3, 1926, as Assistant Superintendent, being the first Indian to be selected in the country as Class I, Officer. He had earlier spent a field season with AM Heron in Rajasthan and had given an excellent account of his knowledge and abilities, both theoretical and practical, and demonstrated a keen interest in fieldwork, so essential for a geologist. His recruitment in the Geological Survey of India was a consequence of this excellent report by Heron, so difficult to obtain from an Englishman who was then resentful of Indians entering in Class I, service.
In the Geological Survey of India, he started his career as a member of the Burma Party and carried out geological investigations in the Chindwin and Shwebo districts of Upper Burma. Work in this area, with immense mineral potential, is required also in sillimanite, barytes, stibnite, coal, lignite, salt and even building stones, besides groundwater investigations. In order to work out the regional geology of this vast but important area, Coggin Brown and Sondhi carried out joint traverses from Loilem to Maukmai, a distance of over 250 miles (400 kilometres), and from Taunggyi to Salween. Later on, Sondhi resurveyed a portion of the area and successfully identified two geological formations on lithological and palaeontological bases. Also, Sondhi traced the lead-silver ore belt northward and reported many other mineral deposits, whereas along with Clegg he reported on the Gyophyu and Nyaunglebin Lakes scheme for gravity water supply to Rangoon. Most of this work, however, remained in manuscript reports.
Sondhi discovered many coal outcrops between the Loian Coalfield and the Minapalaung District and a good lignite deposit in the Tertiary lacustrine deposits in the Kengtung Valley.
During 1936-37 Sondhi accompanied the Sino-Burma Boundary Commission on the northeast frontier of Burma. Basically, his job was to carry out reconnaissance work to ensure that as far as possible no worthwhile mineral deposit was lost to China in the process of demarcating the boundary. However, he was in charge of topographic surveys, transport, etc. In addition, in recognition of the excellent job he did, he was honoured by MBE (Member of the British Empire), a relatively well-respected title for civilians, by the Government of the time. Sondhi was transferred back to Calcutta in 1937, but went abroad on study leave in 1937-38.

Geological Reconnaissance in the Southern Shan States
J Coggin Brown and V P Sondhi conducted Geological Reconnaissance in the Southern Shan States and reported in 1933. Due to limited space, only the significant points could be extracted as follows:-

Taunggyi to Hopong
The area covers map sheet 93/H1. For ten miles east of Taunggyi, as measured along the main road, Plateau Limestones continue. They build the precipitous crags and the ridge that faces a Lower Palaeozoic inlier on the west and overshadows Taunggyi on the east, in consequence of which the road has to make a detour of some miles to the south before continuing in its normal direction. These crags have a general easterly dip with a few minor undulations down to the Hopong plain at Pa-leng, ten miles from Taunggyi.
The rocks seen are all typical representatives of the lower division of the Plateau Limestone, sometimes grey brecciated dolomites friable enough to kicked to powder; often, harder, greyish white, recemented material with a deceptive sandy appearance and occasionally handed with pink. Travertine and secondary limestones are of common occurrence over the flat ground between the first and second steep descents, i.e., between miles 5 and 8.
Along their junction with the older rocks the Plateau Limestones are fossiliferous, showing sections of crinoidal stems, brachiopods, and corals. A cap of similar limestone rests unconformably upon the older rocks about four miles N N W of Hopong. The latter rocks that build up the greater portion of the ridge here, dip steeply to the east, and the Plateau Limestone, shows gentle dips to the northeast, forming the crest of the ridge with peaks of over 5,000 feet in height.

Traverse South of Hopong
The area covers map sheets 93 H1 and H2. Hopong lies at an elevation of 3,600 feet at the head of the narrow plain of the Nam Tamhpak, a stream that flows to the south through the small Shan States of Namhkok, Nawngwawn, Wa yin and Hsahtung, for 86 miles before it turns east to enter the Nam Pawn.
A traverse was made down this valley from Hopong to Namhkok, a distance of 13 miles. Around Hopong the character of the country, although it is underlain by Lower Palaeozoic rocks, recalls the downs of Thamakan, between Kalaw and Taunggyi, in its rounded grassy outlines, bamboo groves, lines of giant aloes and occasional banyan trees, but the valley is hemmed into the north-east and west by limestone hills. For the greater part of the distance traversed, the road lies on the alluvium of the plain or on the lower flanks of the eastern foot-hills. Although exposures are few and far between, there is little doubt that for five- or six-miles Plateau Limestone forms both walls of the valley; thus, at the sixth mile tabular, westerly dipping bands can be seen as steep scarps. The isolated hill of Loi Tang, which rises from the plain to the west of the eighth mile has a thick capping of Plateau Limestone, probably of the younger division, and may be entirely built of this rock.

Hopong to Htamsang
The higher ground east of Hopong, where the road crosses it, has no well-marked direction nor individuality for it consists, at any rate in this latitude, of a series of valleys of enclosed drainage, the winding rims of which give rise to a confused topography. Further south the development of a single ridge with peaks of over 8,000 feet in altitude, forming the boundary between the Hopong and Namhkok States on the west and Mong Pawn on the east, seems to betoken a change in lithological composition. Near mile 22-3 there is a cauldron valley with limestone peaks around it and craggy outcrops continue at intervals to the crest at 22-7. Here there is a change and limestones are replaced by brown-grey and white, sandy shales.

Fossiliferous Upper Plateau Limestone
Beyond these shaly outcrops at mile 23-2 occurs the first of the fossiliferous localities of the upper division of the Plateau Limestone, the organic remains from which enabled Diener to prove its Permo-Carboniferous age. Middlemiss was the first to obtain fossils in this neighbourhood and though it is not possible exactly to determine the different localities he mentions, his descriptions of the rocks themselves cannot be improved upon and for this reason are summarized below. The conversion of the rough cart track which he traversed in 1898 into a modern motor road has destroyed the utility of his distance points as a means of identification.
As measured along the road, the places in which the best exposures of the bryozoan limestones occur at miles 23-7 and 24-1 on the roadside. From representative collections made at these localities, Dr F R C Reed has identified the fossils listed in his paper on the Anthracoliyhic fauna of Southern Shan States. Htamsang Rest House is situated at miles 25-4 and around it and the village further west there are abundant rocky outcrops of the Lower Plateau protruding through the soil cap in all directions.

Htamsang to Mong Pawn
The area covers map sheet no. 93 H/5. After leaving the crest of the ridge with its richly fossiliferous, tabular Permo-Carboniferous limestones at miles 28-3, the road commences its winding descent to the Mong Pawn plain at mile 73-2, and about mile 36-5 again encounters fossiliferous Permo-Carboniferous strata which here border the plain. Between these two exposures, there is a series of rocks consisting in the main of greenish-grey shales, sandy shales, and purple mudstones with less frequent sandstones and a solitary band of limestone. From these rocks, C S Middlemiss in 1898 obtained an impression of part of a trilobite, a gastropod, and an ill-preserved cast of a portion of a Nautilus and some indistinct vermicular markings, but they failed to yield any fossils as a result of Dr Coggin Brown’s earlier examination. He pointed out then that the evidence, scanty as it is, points to the series being older than the Plateau Limestones, while lithologically, especially in the presence of fine-grained sandstones, it appeared to have affinities with the Namhsim (Silurian) beds of the Northern States. Short notes of the remaining trips are: –

Mong Pawn to Loi-Samhpu Pass
The area covers map sheet no. 93 H/5 and H/9.
An unfossiliferous sandy series builds the western flanks of the Loi-Samhpu.

Loi-Samhpu Pass to Loilem
The area covers map sheet no. 93 H/9. Unfossiliferous limestones form the higher eastern flank of the Loi-Samhpu. The Panghkawkao graptolite bed was found to the west of Loilem. Silurian limestone exposures near Loilem itself.

Loilem to Wan Pong
The area covers map sheet no. 93/H9. New fossil localities in Silurian rocks near Loilem. Types of Silurian limestone. The Panghkawkwo graptolite bed. Upper Naungkangyi purple beds. Details of the more important exposures. A remarkable morphological change takes place at mile 65. A predominantly sandy series between mile 67 and Wan Pong. Possible Silurian correlation of the sandy series.

Mr Sandhi’s Traverse from Loilem
The area covers map sheet no. 93 H/9. A series of interbedded limestones and mudstones. Loi Lang is built of Nyaungkangyi mudstones capped by limestone bands.

Traverse to the north of Loilem
The area covers map sheet no. 93 H/9 and G/12. Remains of Pleistocene lacustrine deposits. Mudstone at the 11th mile. Slags of former Iron smelting operations. Silurian horizons probably occur about miles 12 and 13.

Wan Pong to Hsaimong
The area covers map sheet no. 93 H/9 and H/13; 93 G/16;93 K/4 and K/7. The limestone plateau between Wan Pong and Nam Teng. Upper Plateau Limestone on the left bank of the Nam Teng. A Red Bed series overlies the Plateau Limestones. The Plateau Limestones appear again and continue to Hsaimong. Sandy sediments of a slight extent and unknown age near miles 118-5. Character of the limestone topography.

Hsaimong to Kunhing
The area covers map sheet no. 93 K/7 and 129.6 miles from Taunggyi. A steep descent down the Hwe Leng to the Nam Pang. Brecciated Plateau Limestone at Hsaimong. A fossiliferous series between the Plateau Limestone and Red Beds. The shaly sequence. Occurrence of bands of limestone conglomerate. Limestones overlie the shales. A coarse basal conglomerate is followed by a Red Bed formation. Outcrops of the Red Beds between Wan Laikam and Kunhing. Correlation of Mesozoic rocks.

Kunhing to the Salween
The area covers map sheet no. 93 K/7, K/11 and K/12. Red Bed sandstone between 150-6 and 151-7. Chaung Magyi series forms the western bank of the Salween. Nyaungkangyis faulted into the Chaung Magyis.

Wan Pong to Mongnai
The area covers map sheet no. 93 H/9, H/13 and H/14. The southern extension of the Plateau Limestone. Outcrops of the brecciated limestone. Fossiliferous limestone. Alterations of both varieties of limestone. Mesozoic rocks of the south of Hai-pak. A limestone ridge borders the Nam Tawng Valley on the east. Differences between the eastern and western walls of the Nam Tawng Valley in Mong Nai. The Mong Nai Plain.

Mong Nai to Melun (Me-Lawn)
The area covers map sheet no. 93 H/14 and H/15. Older Plateau Limestones around Mong Nai. Thin remnants of Red Beds overlie it to the south. Lower Jurassic preserved by subsidence. The other Plateau Limestone recurs. Acidic igneous rocks not in situ near Melun.

The Old Silver Mines of Mawmai
The area covers map sheet no. 93 H/15. Upper Plateau Limestone between Melun and the old mines. Description of the old lead pits.

References: Coggin Brown, J, and Sondhi, V P, 1933: Geological Reconnaissance in the Southern Shan States, Records of Geological Survey of India, Vol. LXVII.

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