Proceedings

of the Tomsk Technological Institute

of Emperor Nicholas II

Vol. 7. 1907. No. 4.

V. A. Obruchev.

Expedition to Barlyk and Tarbagatai in 1905.

Preliminary Report. 1–21.

Expedition to Barlyk and Tarbagatai in 1905

(Preliminary report).

In the summer of 1905, on the instructions and at the expense of the Tomsk Technological Institute, I made a journey for the purpose of a geological investigation of the mountain systems of Barlyk and Tarbagatai, situated on the border of the Semipalatinsk and Semirechensk regions and Chinese Dzungaria. The expedition included, besides myself, two of my sons, pupils of the Tomsk Realschule, and two fourth-year students of the mining department, N. G. Kozhevnikov and N. S. Morev (who, however, already in the middle of July parted from us and returned). The students were charged with conducting route plane-table surveying and geological investigations, at first under my direction and then independently—both during side excursions, which in this way could be multiplied, and when the whole caravan was moving together, which made it possible to carry out route observations in greater detail. One of my sons was occupied with collecting plants, the other with collecting lower animals; after the students’ departure, the latter also took upon himself the conduct of the route survey and assisted in collecting fossils.

Having left Tomsk on May 17 by railway for Omsk, we lost four days there waiting for a steamer and arrived in Semipalatinsk only on May 27; from there to Chuguchak, chosen as the expedition’s base, it was necessary to travel by post horses. But, on the one hand, having in view the extreme scarcity of available data on the geological structure of this part of the Kirghiz steppe, and, on the other, wishing to acquaint my young companions with the methods of field work and with camp life under the more favorable conditions of wheeled travel, and to prepare them for independent excursions, I decided to lose an extra 9–10 days on this route and to begin the investigations from Semipalatinsk. Therefore drivers with carts were hired for us and for the baggage, who were to convey us

in Chuguchak in 12–13 days, making 40–50 versts a day, which made it possible to carry out at least cursory observations.

Having left Semipalatinsk on May 29, we passed Sergiopol on June 5; over this stretch we turned aside from the postal road only in one place, in order to visit the picturesque mountain group of Arkat, where we spent twenty-four hours. From Sergiopol to the Urdzhar station one could travel in two ways—either along the modern postal road, or along the so-called old picket road, almost abandoned, shorter, and running between the advanced chains of the Western Tarbagatai; we chose the latter and, at the Naryn picket, turned off the road. It turned out that there are two picket roads: one more northerly, leading straight to Urdzhar, the other middle one, coming out at the Burgon picket; our drivers knew neither the one nor the other, and at first we set off along the northern one, but some Kirghiz whom we met reported that this road was very difficult for loaded carts to pass, because of the heavy landslides that had covered it; they led us out onto the middle road, which, however, also proved rather inconvenient for wheeled travel because of gullies, mud, and very steep ascents and descents. With some adventures we emerged again, to the great joy of the drivers, on the third day onto the main postal road at the Burgon picket, whence, bypassing Urdzhar, we drove by a shorter road to the Barakpai picket and then followed the road as far as Chuguchak.

In Chuguchak we found cordial hospitality and broad assistance from the Russian consul S. V. Sokolov, with whom I had become acquainted earlier in Kulja after the expedition to China in 1894; thanks to his help we quickly organized a caravan of riding horses for us and 20 donkeys for baggage and fodder; an experienced guide was found, the Tatar Gaisi Musin from Chistopol, cast by fate onto the frontier of Dzungaria and familiar with almost all the localities of interest to us.

On June 18 our caravan set out from Chuguchak, consisting of five Russians, two Tatars, a Kirghiz, and three Kashgar Turks (the owner of the donkeys and two drivers), with 11 horses and 20 donkeys. We headed south, toward the Dzungarian Gates, the passage famous in history by which the Mongol hordes came from the depths of Central Asia into the borders of Siberia. To these gates, the investigation of which constituted one of the tasks of the expedition, two roads lead from Chuguchak: the more westerly one goes within Russian territory through the Bakhty fortification, but crosses shifting sands and, running through lowland, is of little interest to the geologist; therefore we chose the eas—

route, crossing beyond the Emel River the western spurs of the Barlyk Range, and from Chuguchak to the Tasty River we traveled over Chinese territory. From the camp on the Tasty River excursions were made to the mineral spring Arasan and up the river gorge, into the interior of Barlyk. From the Tasty River to the Terekty River we went almost along the very border, spending the night now in Russian, now in Chinese territory; along this stretch, from the camp on the Kipeli River, excursions were made—one into Mount Katy near the southern end of Lake Ala-Kul, the other up the gorge of the Kishili into the interior of Barlyk. From the Terekty River we crossed the Dzungarian Gate past the northern shore of Lake Dzhalanash and then went for two days southward, along the western margin of the gate, at the foot of the Dzungarian Alatau; here a small excursion was made up the Tonty River. On the third day we turned toward Lake Ebi-Nor and stopped among the gates in the valley of Ulan-Kol, by the hills of Kok-adyr-kontuk; from there an excursion was made to the lake and to the mountains of its western shore.

Lake Ebi-Nor was the southernmost point reached by the expedition; on July 3 we turned back and went northeast, into the interior of the Maili Range—the broad southern chain of the Barlyk system; for four days we crossed the high mountains—Maili and Konur-obo—and emerged onto the Kup River, where the caravan divided: one party set out through the Arba-kezen Pass into Barlyk, intending to visit the highest part of the range—the Kert-tau Mountains (which, however, could not be accomplished because of bad weather), while the other went down the Kup valley, crossed the southern spurs of Barlyk, and then, through the more easterly Altyn-Emel Pass, came out onto the Chuguchak plain; on the Kara-bura River both parties met, and on July 14 the expedition arrived in Chuguchak.

On July 20 the caravan, having rested and having been somewhat reduced owing to the departure of the students, moved northward, toward Tarbagatai; the first two days were devoted to examining the rocky ridge of the Bakhty Mountains, which form the foremost group of Tarbagatai, projecting far to the south; on the third day we entered the bounds of the range itself, along the road leading to the well-known Khabar-asu Pass, and after four more days were already on the Espe River at the northern foot, near the front ridge of Dzhaksy-arganaty, into the interior of which an excursion was made the following day. Then we headed east, crossing the northern spurs of Tarbagatai, to the Bosha 3rd River, where, already in view of the gorge of Issyk of the Kandy-su stream, which separates Tarbagatai from Manrak, we turned south and crossed the Teres-airyk Mountains, which form the northern chain of Tarbagatai. Proceeding farther along the Teres-airyk River to its turn northward, we went along the Chilikty valley to

to the low pass of Kuzeun through the main chain of the Tarbagatai, along which runs the cart road from Chuguchak to Zaisansk; on the southern slope of the ridge we again turned eastward, crossing the southern spurs among numerous streams flowing into the Ak-emel River. The wholly imperceptible Bai-murza pass in the upper reaches of the Ak-emel brought us, on August 4, again into the upper reaches of the Chilikty valley, to the Chagan-obo guard post, where in summer a hundred Cossacks from Zaisansk are stationed in camp. Leaving with the hundred the collections already gathered, part of the baggage, and the most tired donkeys with their ailing owner, we returned to the Chinese frontier by way of the Kergen-tas pass in the Kodzhur Range, and on the following day reached the ruins of the temple of Matenya on the Dzhamungul River, in the western part of the Koby valley, known from the reports of Przhevalsky, Pevtsov, Kozlov, and Roborovsky. To the north of this valley rises, with a steep wall and without foothills or spurs, Saur, on which, here and there, eternal-snow summits tower and small glaciers are visible; to the south, the bare and rocky Semistai rises even more steeply; both ridges have scarcely been studied and attracted the investigator.

But the late season no longer allowed us to penetrate farther south; it was time to turn toward Zaisansk, i.e. northward; therefore we moved to the foot of Saur and devoted one more day to an excursion deep into the range along the Kizil-uzen River, in whose valley clear signs of considerable former glaciation were found.

On August 10 we set out westward and, by the flat Chagan-obo pass, which connects Saur with Kodzhur, found ourselves again in the basin of the Chilikty valley, although for a whole day more we still went along a narrow gorge amid the picturesque converging spurs of both ridges, covered with deciduous forest; on August 12 we emerged into the Chilikty steppe; on that day another excursion was made to the foot of Saur along the Karagaily River.

On the following day we passed the Chagan-obo guard post and by the shortest route along the cart road went to Zaisansk; that day we spent the night in the southern foothills of Manrak, on August 14 crossed to the northern slope of the ridge, and on the 15th pitched our tents for the last time 5 versts from Zaisansk.

Since it was necessary to return to Tomsk by the beginning of September, no more than five days remained for the study of the whole of Saur and Manrak—a period far too insignificant; moreover, throughout the entire second half of the summer we were pursued by bad weather; rarely did a day pass without rain, most often in the form of thunderstorms with more or less heavy downpours, and sometimes with hail; the same weather continued even after our arrival in

Zaisan, so that it was necessary to decide to discontinue the investigations, postponing everything not completed until the following year. Three days were spent packing the baggage and collections and disbanding the caravan; on August 19 we set out by post horses and, via Kokpekty, Ust-Kamenogorsk, and Zmeinogorsk, arrived in Barnaul on August 24, and on the 28th returned to Tomsk by steamer.

The results of the expedition are geological diaries, hypsometric materials, route surveys of those localities for which there are no detailed maps, a collection of rocks (about 2,000 specimens) and fossils of the Devonian, Carboniferous, and Tertiary systems (about 500 specimens); all these materials were deposited in the Geological Cabinet of the Institute, while the herbarium was transferred to the Botanical Cabinet of the University.

After this preface we shall proceed to the description of the localities studied, which, in view of their diversity, is most conveniently arranged by chapters.

I. The Kirghiz Steppe from Semipalatinsk to Sergiopol (May 29–June 5).

From the town of Semipalatinsk to the first picket, Uluguz (25 versts), the road runs across a plain with dry clayey-sandy loess-like soil; about 8 versts before the picket, flat hills appear, but their composition remained unknown, since night overtook us here. The picket is situated in a small valley among flat hilly ridges, on the bank of a winding channel, in which puddles of dirty water were still preserved in places.

From Uluguz to the Arkatyk picket (23 versts) the road at first goes uphill along the same valley among flat hills composed of gray-green and gray, more or less thin-bedded, fine-grained sandstones, interbedded with gray and gray-green calcareous-clayey shales and cut by numerous quartz veinlets; in the sandstones, small cubes of pyrite are embedded in places; these are apparently the same sandstones and shales of the Devonian system that crop out on the right bank of the Irtysh River at the ferry of the town of Semipalatinsk, but there their strike is NW 348° and dip NO < 80°, whereas here the strike is NW 345° and dip SW < 50° at 4 versts from Uluguz, NW 278° and dip NO < 70°, and NO 70°–80° with dip NW < 36° somewhat farther on. On the 10-verst map of Western Siberia these hills are called Dzhaksy-biish-cheku.

After crossing over them, the road enters similar flat, but higher hills, Bel-terek, consisting of the same sand—

sandstones and slates, but with an even greater quantity of quartz veins; some hills are white from the fragments of quartz covering them; on the southern slope of the area of hills, west of the road, there is a whole group of similar white hills, among which reddish-yellow ones stand out sharply; judging by the fragments on the surface of the soil, these too consist of quartz, but are rich in nests of ocher and clayey ironstone.

From the picket of Arkalyk, situated at the foot of the Bel-te-rek hills and obtaining brackish water from a shallow well, the road goes for 10 versts along the broad valley of the drying stream Karganai-bulak, with saline soil, and then enters the chain of low Arkalyk mountains, extending WNW–OSO and facing the aforementioned valley with a rather steep slope; the former picket of Arkalyk was located in a small valley of the northern slope of these mountains, near springs. The mountains are composed of greenish, more or less strongly altered porphyry-porphyrite tuffs and breccias, interbedded with gray and greenish-brown limestones; the strike of the beds is WNW 280°–305°, dip NE < 55°–80°; in the NE and ENE direction, veins of altered porphyrite and quartz porphyry run through these rocks.

The southern slope of the Arkalyk mountains is considerably longer and more gently northern; it is dissected into spurs breaking up into groups of flat hills. Having descended from the mountains, the route crosses two branches of the valley of the Sary-bulak River, separated by flat hills; the bottom of the valleys is saline, with thickets of chia; here and there efflorescences of salts are visible.

Beyond the Sary-bulak valley the route crosses the Kara-dzhal mountains, belonging to the same Arkalyk chain; at the pass, an outcrop of quartz hornblende porphyrite is encountered in the form of a vein, striking ENE. On the southern slope of these mountains, in a transverse valley with a dry channel, stands the Ashchi-kul picket (27 v.), obtaining water from wells; near it outcrops of light-brown hornstone, striking WNW, were observed.

From the Ashchi-kul picket almost as far as the Dzhargast picket (21½ v.) the route crosses flat hills forming the broad, irregularly shaped group Idzhon; among the hills there occur small depressions with salt marshes and valleys opening eastward into the extensive basin of the lakes Kara-sor, Ashchi-sor, and Tuz-kul; in the hills lie gray and green porphyrite tuffs, passing into sandstone with more or less clear coarse-spherical separateness; in one place outcrops of brown orthophyre were observed, probably a vein striking NE 45°, among quartz-porphyry tuffs.

From the south this flat-hilly locality is bounded by a more sharply expressed and higher chain of flat mountains, Dzhartas, which, like the Arkalyk mountains, have a steeper and shorter northern slope and a longer, gentle southern slope; in a small gorge of the northern slope, watered by a streamlet, is the Dzhartas picket, below which the slopes of the gorge consist of green porphyritic tuffs, cut by a series of thick veins of hornblende granite-porphyry. Above the picket there appear contact hornblende-argillaceous schists, with strike NO 30° decl. SO < 30°, and then the road enters a fairly large basin, which in the post-Tertiary period was a lake; in the coarse clayey and silty sands of this lake the channel of the Dzhartas streamlet is incised by 2–3 sazhens. From the southwest the basin is bordered by the Ak-dzhal mountains, apparently forming one whole with the Dzhartas mountains: on approaching them, but still within the basin, outcrops were encountered of biotite-hornblende granite-porphyry, quartz and felsitic porphyry, and in the Ak-dzhal mountains again porphyritic tuff, with strike NW 325° decl. NO < 45°, and granite-porphyry.

From the Ak-dzhal mountains the road gently descends into a broad valley, on the bottom of which occur outcrops of dark-gray hornblende-argillaceous schists, with strike NW 325° decl., a steep saline depression with efflorescences of salt and, here and there, fragments of dark-rose quartz porphyry polished by sand; in the southeastern part of the valley are spring-fed lakes surrounded by reeds. From the south the valley is bounded by the Kosumbet mountains, which also have a sharply delimited, short and steep northern slope, and a long, gentle southern one, breaking up into irregular groups of hills; on the northern slope there are exposures of porphyritic tuffs and dark-gray argillaceous schists, with strike NW 325°, decl. almost vertical. From the pass of the ridge to the south there is already visible the picturesque group of the Arkat mountains, with sharp alpine forms. The Kizil-mulla picket (26 versts from Dzhartas) is situated at the southern foot of the Kosumbet mountains, on the edge of an extensive saline basin with several small lakes, lying between the spurs of the chain; on the slope of the spur behind the picket there are exposed gray-green porphyritic tuffs and quartz-argillaceous schists, with strike NW 325–330°.

From here to the Arkat picket (26½ versts) the road runs along the broad Espe valley, which separates the Dzhartas mountains from the uplands of Arkat, Burkat, and Kizil-dzhar; through the middle of the valley flows, from SO to NW, the small Espe river. The bottom of the valley is steppe, in places more or less solonetzic, with saline depressions; among

scattered groups and ridges of low hills with outcrops of bedrock; on such hills to the north of the Espe River there occur ruined outcrops of felsite porphyry and red jasper, cut by quartz porphyry. South of the river, in similar little hills, there lies biotite granite with veins of quartz; farther on are porphyritic and porphyry tuffs, and, in large blocks lying amid the steppe, gray felsite. About 5 versts before the picket, to the left of the road, begin the hills of Kizil-Dzhar, on which gray porphyry tuffs and quartz-clay slate are exposed.

From the west, hills adjoin the picket, consisting of yellow biotite granite, intersected by veins of more fine-grained granite and quartz porphyry and containing inclusions of schistose rocks altered by contact; the veins strike NW 350°—NO 10°; cracks in the granite are NW 300° and NO 25°; in places veins of quartz occur (NO 40°).

To the west and northwest of the Arkat picket rise the picturesque mountain groups Arkat and Burkat, sharply distinguished by their deeply dissected alpine forms, fantastic cliffs, high precipices, and comparatively significant relative height amid the generally monotonous and smoothed landscape of the whole route from Semipalatinsk to Sergiopol. Both groups are granite laccoliths, completely freed from their former covering of sedimentary rocks and deeply dissected by erosion and weathering; Burkat represents a narrow and long laccolith, elongated from north to south, while Arkat is no fewer than two laccoliths of considerably larger dimensions, with a total diameter of about 15 versts from west to east and about 8 from north to south. For lack of time we examined only the eastern part of Arkat, where we encountered exclusively pinkish-yellow, medium- and coarse-grained biotite granite with beautifully developed jointing in various directions, composing picturesque pillars, walls, hills of the most varied forms, adorned with columnar and spherical rocks, caves, and wind-eroded niches. A whole series of successful photographic views will allow this part of Arkat to be illustrated in the full report in sufficient detail.

At the eastern foot of Arkat a vein of white aplite was encountered, with a strike of NO 87°, and at the northern foot of Burkat—an outcrop of gray metamorphic sandstone, striking NW 290° and dipping NO ∠ 65°—a remnant of the former envelope of the laccolith.

From the Arkat picket to the Aldzhan-Adyr picket (24 versts), the road runs along the valley of the Ainabulak brook (in places completely

drying up), cut into the Kara-Cheku mountains; the latter are composed of dark-violet crystalline tuffs of quartz porphyry, containing in places small pieces of plagioclase porphyrite and melaphyre; in places these tuffs are pink and green, approaching breccia; strike NW 330°, dip SW ∠ 70°; the jointing is irregular; the outcrops have the form of irregular rounded heaps and ridges both on the slopes of the valley and on its floor, sometimes with hollows of weathering. Nine versts from the picket an inconspicuous pass leads into a similar valley of the southern slope of the mountains, of the same meridional direction, but wider; gradually the mountains (hills) become lower and finally disappear to the west of the road, whereas to the east of it the low hills and ridges of Chor of the same composition continue farther on. The Aldzhan-Adyr picket is situated at the foot of these hills, which end here; from the east and from the west broad valleys open out, so that altogether a rather extensive plain is formed.

From this picket to the next, Uzun-Bulak (24¼ versts), the road goes for 6–7 versts through the Aldzhan-Adyr mountains, running at first along a broad meridional valley, which branches off from the above-mentioned plain and has two wells at its mouth. These mountains in the northern part are composed of the same porphyries, but in the southern, in the little hills by the road, outcrops of green hornblende porphyrites and their tuffs begin. The Aldzhan-Adyr mountains end on the right bank of the Karagan-Ayryk River, flowing WNW; to the south of it lies a flat, hilly locality, bounded on the east by a gradually receding chain of the same mountains*) and composed of the same porphyrites and tuffs, judging by the few outcrops.

The Uzun-Bulak picket is situated on the bank of the brook of the same name, at the outlet of the last of the broad chain of the Inrekei mountains; the northern part of these mountains, extending NW—SO, up to the headwaters of the Uzun-Bulak, consists of melaphyre, melaphyre tuffs, and conglomerates containing, among other things, large pebbles of granite; the road crosses this chain along the gorge of the brook or near it, then runs for some time along the valley between the northern and southern chains, and finally crosses the latter, descending afterward along the valley of the southern slope, which rapidly widens and gradually turns into a hilly steppe. The road runs closer to the foot of the left slope, crossing in places flat hills and spurs. At

*) In the front part there are more low ones; behind, more high ones with rocky ridges and groups; these are apparently granite laccoliths, like Arkaty.

in this space the same melaphyres and tuffs were first observed, alternating with red shales and sandstones, with a strike of NW 315–330°, in places replaced by green porphyrites and their tuffs. As the valley widens, in the hills of the left slope there appear outcrops of light hornblende granite and granite-porphyry, forming veins with an ONO strike, and small masses among the dark contact-metamorphic hornstone shales; the isolated rock Kizyl-koi-tas, rising in the middle of this valley, is apparently also granitic. Before the Inrekei picket (26¼ versts from Uzun-bulak) the road crosses another belt of rocky hills, forming a spur of the same Inrekei mountains and composed at first of melaphyre conglomerate, then of contact hornstone shales, with a strike of NW 280°; at the picket, situated in a broad recess between the spurs of the Inrekei mountains, a plain with saline depressions (water from a well), in the hills adjoining it to the north, green tuffs and contact hornstone shales occur, with a strike of NW 280°.

From the Inrekei picket to Altyn-kalat (22¾ versts) the road runs across a broad plain, in places crossing small hills and hillocks; along this stretch there were first encountered outcrops of melaphyres with a thick vein of white quartz, 2–3 arshins wide, with a strike of NO 75°, containing inclusions of pyrite; these same rocks, as well as green porphyrites, strongly epidotized and with numerous quartz veins, occur farther on in low hills and outcrops amid the steppe; in only one place were light quartz schists encountered; to the east, at some distance, there extends a regular chain of higher hills (Aityrdzhal on the map?) with reddish slopes; to the west only low hills are visible. At the Kara-mola grave (about 12 versts from the picket) the road crosses higher hills, from which a view opens southward over a broad valley, bounded on the horizon by the flat heights of Bii-tal, on the northern slope of which the picket is located; in the Kara-mola hills porphyritic tuff and a green epidote-chlorite schist, likewise derived from tuff, were observed.

From the Altyn-kalat picket to the town of Sergiopol the road (26¼ versts) runs through more dissected country, crossing first the low Bii-tal mountains, and then the higher Chingiz range, which forms the western continuation of the Tarbagatai. In the Bii-tal mountains, on the northern slope, another porphyritic tuff was encountered; near the pass, brown and greenish felsites and felsite-keratophyres extend in ridges, with a strike of NO 5° dipping SO at 55°. On the southern slope the road pro-

it runs for several versts over low hills alternating with basins and small valleys; here the same felsites continue, but then melaphyres and porphyrites appear, and the road often follows the contact of felsites and melaphyres, extending NW 5–10°, so that the former remain on the right and the latter on the left. Farther on the hills become much lower and spread apart; the route runs along the valley of a small brook of the Ayaguz River basin; on the left slope a ridge of felsite hills stretches in the distance, while on the right there are knolls of felsite, brownish quartzose porphyry, and melaphyre, in places cut across by the road.

Beyond the 15th verst the route crosses a small river flowing toward ENE (joining the above-mentioned brook) in a broad valley with reddish soil and solonetz patches; beyond the river begins a gentle ascent to the pass across the Chingiz Mountains, on which outcrops of porphyritic and felsitic tuff, melaphyre, and limestone were encountered; at the summit, west of the pass, melaphyre occurs, and on the slope toward the route—orthophyre; east of the pass, dorite and altered sedimentary rock are noted. From the pass an extensive view opens up: to the S, SW, and SE the whole area consists of low mountains and hills separated by broad valleys; to the southeast, behind them, rise the flat but high massifs of Tarbagatai. A long, but fairly steep descent leads to the town of Sergiopol, situated on the right bank of the Ayaguz River, which flows along a broad valley from ENE to WSW; in the bluff of the right bank below the barracks, outcrops of bluish rock (melaphyre?) are visible.

II. Western Tarbagatai (June 5–11)

The first stage from the town of Sergiopol to the Nizhne-Naryn peak (31 versts) we traveled along the postal road to Chuguchak, which runs through the valley of the Naryn River, a left tributary of the Ayaguz River, bounded on both sides by flat heights and reaching several versts in width. The river flows at the foot of the heights of the right slope, often washing more or less high and picturesque cliffs of melaphyres, their tuffs and breccias, apparently composing a broad belt of the lower mountains of this bank. The mountains of the left slope, on the contrary, stand far from the river and are separated from it by a high terrace, in places dissected by more or less broad and deep ravines and apparently consisting of post-Tertiary pebble beds underlain by the same melaphyres—judging from individual outcrops on the slo—

ravines both on the right and on the left bank of the river. About 10 versts from Sergiopol, amid the monotonous steppe of the left bank, to the south of the road rises the isolated hill Karaul-tyube, elongated, apparently, from E to W and rising some 30–40 sazhen above the terrace.

Ten versts before the picket, the terrace of the left bank no longer reaches such a height above the level of the river as in the lower reaches of the valley (where it was 6–8 sazhen); here there are also fewer ravines, the steppe is more level, and to the right a road branches off, shortening the distance by bypassing the picket. At the picket the post road turns SSE along the valley of the left headwater of the Naryn River, while we proceeded along the old picket road, which runs along the valley of the right headwater of the river, preserving the same SO direction and the same character: the river still flows at the foot of flat heights on the right slope, which in places form melaphyre cliffs; the road goes along the terrace of the left bank, at first dissected by ravines into flat hills with outcrops of melaphyres, and farther on more level; to the south, at some distance from the road, there also stretch flat heights composed of melaphyres.

About 12 versts from the picket, the heights of the right slope are interrupted by a wide valley running to the N; on its gentle slopes are visible patches of reddish talus—the melaphyre area has apparently come to an end. Indeed, 3 versts farther on, near the western end of the Ak-chauly Mountains, on both banks of the Naryn River, there are outcrops of biotite-hornblende granite with thick veins of pink felsite, and one may suppose that these rocks form a considerable district downstream along the Naryn River as far as the above-mentioned valley.

Here we had to turn off the northern picket road, which was to go upward along the valley of the Right Naryn River north of the Ak-chauly Mountains; the Kirghiz whom we met assured us that this road was passable only for empty carts, and guided us onto the middle picket road, which branches off from the highway in the valley of the Left Naryn River and runs south of the Ak-chauly Mountains. We drove several versts without a road, crossing the flat heights of the left slope of the valley of the Right Naryn River, composed of melaphyres, in places with thick veins of quartz, and emerged onto the middle road somewhat west of the former Ai picket, on the river of the same name, which flows from the Ak-chauly Mountains and breaks through the Konur-chauly Mountains by a long gorge; the latter separate the middle road from the highway, which turns SSW in order to go around them; near the Ai River, in the Ak-chauly Mountains, rises a higher group, apparently also of melaphyre.

Beyond the Ai River the road ascends to a flat saddle connecting the Ak-chauly Mountains with the southern mountains; both these and the others here are more…

flat, and at first the melaphyres on the southern slope apparently give way to granites, judging by the changed color of the outcrops and by the boulders found on the road. The latter then runs for 1–2 versts from the foot of Ak-Chauly over level terrain, well irrigated, in places divided up for arable fields and occupied by the summer camps of the Kirghiz; to the south all the streams flowing from Ak-Chauly merge into one river, running westward to the Ai River; beyond it are visible very flat heights separating its valley from the road.

Closer to the very left tributaries of the Ai River, on the southern slope of Ak-Chauly, the melaphyres again displace the granites, reaching in places to the very foot; they are associated with tuffs and breccias containing large fragments of light-gray and pink fine-crystalline limestone, which evidently occurs closer to the axis of the ridge.

From the basin of the Ai River the road crosses over into the basin of the Karakol River, passing at the very foot of Ak-Chauly; here the terrain is more dissected, since the right tributaries of the Karakol flow in more deeply incised valleys, separated from one another by more or less broad ridges. In the hills of the southern foot of Ak-Chauly, granites appear here again, forming an irregular belt, about 100 sazhen in visible width, cutting in tongues into the region of the melaphyres, which still compose the main part of the southern slope; the granite is pinkish-brown or brown-red, poor in colored constituents and converted by pressure into a fine-grained breccia. The main summit of Ak-Chauly, rising above the rocky melaphyre knolls of the southern slope and visible for a considerable distance, has the form of a blunt irregular pyramid and consists of a light-colored (pinkish) rock with indistinct bands—probably of the above-mentioned crystalline limestone.

Toward the middle course of the Karakol, a fairly large river, the belt of granites widens, pushing the melaphyres deeper into the ridge; this river apparently runs near the aforementioned main summit of Ak-Chauly; in its bed, large boulders represent various melaphyres and porphyries, green melaphyre schist, green conglomerate, granites, felsite, and black quartz porphyry. Beyond this river, the nearest mountains of the southern slope apparently consist entirely of granites. To the south of the road, 4–5 versts away, stretches a low hilly ridge, in places with rocky knolls and cliffs; at its northern foot all the streams flowing from Ak-Chauly merge into a single channel, forming the Karakol River.

The main course of this river, abundant in water and with a turbulent current, the road crosses several versts farther on, at the place

at its exit from the gorge in the Akt-chauly mountains, the walls of which are composed of red granite; in the boulders a gray limestone is also noticeable here; along the left bank stretches the aforementioned ridge, which here joins with Akt-chauly and presents granite precipices; on the right bank the remains of the former Karakol picket are visible.

Beyond the Karakol River the road crosses this ridge, which here rises up to 200 m above the level of the river and is composed of granite, hornblende porphyrite, and tuffs of the latter; the descent leads into the valley of a small stream, opening to the NW, apparently still into the Karakol gorge in the Akt-chauly mountains, which farther on are already called Kizil-beldeu (“red sash”) and, judging by the color of the outcrops, consist entirely of granite. The road runs farther parallel to this ridge over terrain that presents good meadows on broad ridges separated from one another by valleys, which to the west drain southward into some river parallel to the Karakol, while to the east they open northward into a broad valley (the basin of the Teke River?), situated along the foot of Kizil-beldeu; judging by the rare outcrops, these ridges are composed of porphyritic tuffs. Behind Kizil-beldeu and farther to the NE, high but short chains of the true mountains of the Western Tarbagatai are already visible here, with rocky flat-toothed crests and steep slopes, advancing in echelon fashion one after another. To the south of the road, a few versts away, stretches a high flat ridge, parallel to Kizil-beldeu, i.e., extending NW 310°.

Farther on, the road begins to deviate more to the south, at first along the valley of a small stream, where coarse-grained quartz-hornblende diorite is exposed; then along a long and broad spur between two valleys, where among the same diorite, passing into aphanite, outcrops (veins?) of felsitic porphyry were encountered. At the southern end of this spur, a steep and stony descent, very inconvenient for carts, amid outcrops of coarse-grained hornblende granite, leads through the gorge of a small stream out of the mountain region, or rather the foothills of Tarbagatai, into the area of broad and flat piedmont ridges north of the Teres-bakan picket. Here the road turns again to the SE, crossing these ridges at a short distance from the foot of the first chain of the foothills (probably Mount Atabai of the 10-verst map, published by the Omsk Staff, which in the locality described corresponds little to reality). This chain at first consists of granite and quartz diorite, and farther on, near the Dzhemal River, of various porphyry-porphyrite breccias and tuffs. West of this river the ridges on the right (to the south),

from the road form several flat summits, while the Atabai mountains become higher and rockier; finally, along the valley of the Ichan-su River the road emerges from the area of ridges, the southern end of which is a high terrace composed of ancient pebbles covered by a stratum of loess.

After traveling several versts at the foot of the ridges, we again turned south and, along the left bank of the broad channel of the Terekty River, came out onto the postal road somewhat east of the Burgon picket. At the place where it is crossed by the postal road, the Terekty River flows in a broad ravine, cut several sazhens into the soil of the steppe; in the bluffs there is exposed a stratum of loess, rather coarse, stratified and porous, with ordinary shells and small marl concretions, 3–4 arshins thick, underlain by fine silty laminated sand, in places with interbeds of small pebbles and rubble.

Farther on we proceeded by the shortest route to the Barakpai picket; then the postal road goes NE to the Urdzhar station, and then descends SE to the same picket. Our road at first runs along the dry steppe of the left bank of the Terekty River, then rises onto the flat terrace that bounds the valley of this little river on the east (a similar flat terrace is visible to the west of the river), and a few versts farther on crosses the valley of the more considerable Urdzhar River, bounded on both sides by two ledges of the terrace, in places with bluffs exposing strata of loess. Beyond the Urdzhar River, as far as the next river, Kusak, the road runs not far from the southern foot of the flat elevation Kotan-karym, which to the west, toward the Urdzhar River, in places (north of the road, at versts 8–10) breaks off steeply, presenting exposures of stratified soft rocks of a pink color, probably of the Gobi (Tertiary) series, lying horizontally. The southern gentle slope of this elevation presents an exposure only in one place, at the SE corner, where at its foot a small spring flows out at the bottom of an artificial basin; here only unstratified loess is visible, with a thick, 1-arshin concretionary bed of cavernous-nodular structure, consisting of brownish-gray marl and lying not far below the surface. Farther on the road crosses several rivulets, Kusak and Nadala; in the bank bluffs of the broad ravines loess is likewise visible, underlain by stratified sands. Beyond the last stream the road runs SE across a reed-covered solonchak steppe, and before the Barakpai picket comes out onto the road.

This picket, situated amid a dreary steppe with marshy and solonchak depressions, obtains water from abundant

of clear springs, issuing in several places at the bottom of a shallow hollow, at a depth of 2–3 arshins from the surface of the steppe; the water gushes forcefully from numerous horizontal and vertical openings in gray and yellow silty clay, which is exposed on the slope of the hollow and above the springs; by means of a dam the hollow has been turned into a pond.

As far as the next picket and the settlement of Khatyn-su (Mukancha, Ivanovka), the road runs across steppe with solonchak depressions, in places marshy and overgrown with reeds; to the north of the road, amid the steppe, isolated hills rise in two places: Bala-tobe to the NE of the Baraktai peak and Dzhai-tobe to the NW of Khatyn-su peak. The latter lies not far from the road and therefore could be visited; it consists of dark-green and dark-brown porphyry breccias and tuffs, occurring in thick beds, with a strike predominantly NW 305° and a dip NE < 60–90°; the cliffs and fragments are in places covered with a black crust (desert varnish). Viewed from the west and east, the mountain has the appearance of a flat dome, cut into two parts on the northern slope by a deep hollow of latitudinal direction; from the south it rises steeply above the steppe (the loess soil of which, already at a considerable distance from the mountain, becomes finely gravelly), and on the north it is bordered by a gentle pedestal.

The Khatyn-su picket and the rather large reserve settlement of Little Russians, Mukancha or Ivanovka, are situated on springs and irrigation ditches from the Khatyn-su River amid a solonchak and reed steppe; the clean white clay-walled huts and the tall trees in the front gardens at each house present a cheerful picture amid the dreary steppe, which stretches 10 versts eastward, to the foot of the extensive group of flat hills Kizil-chauly and Baltabai. In the hills inspected in several places north of the road there occur dark-gray metamorphic schists—namely andalusite, biotite, feldspathic and clayey-schistose hornfelses—which originated from sedimentary rocks altered by contact with granites; the latter are predominantly biotitic and form among the hornfelses more or less considerable stock-like bodies; smaller outcrops, as well as bedded and other veins among the hornfelses, consist of aplites, microgranites, and, more rarely, quartz porphyry, evidently representing offshoots of the same granitic massif. The strike of the hornfelses is predominantly NW 305–330°, the dip variable, but for the most part steep. In the more significant granite outcrop in the central part of Kizil-chauly one can see fine examples of weathering niches and caves.

The eastern part of Kizil-chauly is an undulating plateau, which along its eastern edge is dissected by ravines into broad ridges; in one of the ravines stands Peak Atagai, below which, in the ravine, a pinkish-yellow coarse-grained biotite granite is exposed in places. One verst below the picket, abundant springs of excellent water gush forth from the granite outcrop onto the floor of the ravine; for some reason they are considered sacred. Here the coarse-grained biotite granite is cut by several veins of fine-grained two-mica aplite, with a strike of NW 330°, and of coarse-grained pegmatite, with a strike of NE 30°.

Descending from the ridges of the eastern part of Kizil-chauly, the road crosses a broad lowland irrigated by the streams Lai and Teres-bakan and then goes SSW through the interval between the mountains Baltabai and Ak-irek to the west and Arkarly to the east; the northern part of the latter, cut off from them by the valley of the river Kutui (which is formed from the Lai and Teres-bakan), consists of the very flat Kaichi hills, which the road then crosses. In these hills, small ruined outcrops consist of altered (epidotized and calcitized) melaphyre and jasper-like red and green altered shales with veinlets of quartz in the western part of the hills, and of greenish-brown felsite, felsite porphyry, and tuff in the eastern part.

From these hills as far as the frontier fortification of Bakhty (Zakharovka), and farther to the Chinese town of Chuguchak, the road runs across a plain, in places a dry, scorched steppe, but for the most part a solonetz steppe, with thickets of chia, reeds, and patches of solonchak with white efflorescences of salts; amid this steppe, along the streams flowing down from Tarbagatai, the oases of Bakhty and the much more considerable Chuguchak oasis are green. To the north, about 10–12 versts above this plain, there rises steeply a bare, rocky range of the Bakhty mountains, with a jagged crest—a high outpost of Tarbagatai, whose blue chain, with a crest relatively little dissected and with individual snow-covered summits, stretched in the distance all the time from the moment we left for Peak Burgonsky. To the south, at a considerably greater distance, there also appeared the Dzungarian Alatau with numerous eternally snow-covered summits, separated by the broad gap of the Dzungarian Gates from the lofty, but less snowy Barlyk, with a broad belt of northern foothills; in the Gates one could make out the blue surface of Lakes Sasyk-kul and Ala-kul. Into this deep, mysterious gap between two high ranges, veiled in the bluish haze of Central Asia, we now had to direct our steps.

III. Barlyk, the Dzungarian Gate, and Eastern Tarbagatai

(June 18–August 15).

Since the geological investigations of these localities continued also in 1906, for the present report I confine myself to a brief account of the results of the observations of 1905.

In the area visited in 1905, the following geological formations are widespread: among the sedimentary rocks, the Devonian and Carboniferous deposits have the greatest distribution; in places they are rich in petrifactions and consist of various clayey, siliceous, and quartz schists, sandstones—chiefly fine-grained, hard, often tuffaceous or passing into tuffites and true tuffs of porphyrites and melaphyres; also abundant are more or less hard schistose clays; marls and limestones occur more rarely. These rocks were found both in Barlyk and Maili-Dzhair, as well as in the Dzungarian Alatau to the south, in Eastern Tarbagatai, Manrak, and Saur to the north; and not only on the high ridges, but also in the foothills and even on the smoothed hills among the valleys.

The Silurian and Mesozoic formations still remain in question; it is possible that some ancient schists, sandstones, and limestones occurring among the Devonian deposits will prove to be Silurian, while the varied sandstones, conglomerates, and schistose clays of the northern slope of Manrak will have to be assigned to the Mesozoic (Jurassic?).

Ancient gneisses and crystalline schists of Archean age apparently are entirely absent; metamorphic schists, chiefly in the form of various hornfelses, are in places fairly widespread, probably representing Devonian and Carboniferous deposits altered by contact with granites. In the Dzungarian Gate, in the hills of Ulan-kol near Lake Ebi-nor, remnants of a schistose cover on a granite massif are visible, with excellent examples of the injection of schists by granite and their transformation into biotite gneisses and hornfelses.

Among the massive crystalline rocks, the greatest distribution belongs to granites, chiefly biotite granites, forming large and small massifs and numerous veins (aplitic and granite-porphyry); less common are syenites and various porphyries (quartz, felsite, syenite, orthophyres, and keratophyres), usually in the form of veins, more rarely small massifs. Among the plagioclase rocks the most common are diorites and hornblende—

quartz porphyries in the form of veins and small massifs; the latter are associated with tuffs and breccias; much more rarely, apparently, diabases and augite porphyries occur, but, on the other hand, melaphyres are very widespread, forming entire belts both in the ranges and in the foothills, and accompanied by tuffs, breccias, conglomerates, which often alternate with Devonian or Carboniferous deposits. Peridotites and the serpentines associated with them occur in several places in the Maili and Konur-obo ranges. The more recent igneous rocks (rhyolites, trachytes, phonolites, basalts), apparently, are entirely absent in the area investigated.

The tectonics of this locality is very complex; the Paleozoic rocks are very strongly dislocated and form steep folds, apparently sometimes overturned; moreover, their strong dislocation is noted not only in the central parts of the ranges, but also in the foothills, as well as in the smoothed hills among the valleys; the strike of these folds is variable, with NW and NNW predominating, but NO and ONO also occur quite often, and one may think that the folding dislocation of the ancient sedimentary rocks was repeated twice, with the NO directions being the more ancient. The Mesozoic (?) rocks of the northern slope of Manrak are less strongly dislocated, while the Tertiary rocks are still weaker or lie horizontally.

The modern relief of the locality, however, is determined not by folding, but by disjunctive dislocation: the Saur, Manrak, Tarbagatai, Barlyk, Maili, and Konur-obo ranges (probably also Kodzhur, Urkashar, and Dzhair) are horsts, often stepped; the intervening valleys between them are grabens, for the most part diagonal (relative to the strike of the folds of the Paleozoic rocks); such are the Chilikty valley, the valley of the Emel River, the valley of the Kup River, and the Koba valley; the Dzungarian Gates (the valley of Lakes Ebi-nor, Dzhalanash, and Ala-kul), separating Barlyk and Maili from the Dzungarian Alatau, which once formed a continuation of the former, represent the same kind of graben. Small ridges of ancient rocks, situated among the valleys, such as, for example, the Katy Mountains in the Dzungarian Gates, the Arasan massif, and the Arkarly Mountains in the valley of the Emel River, probably represent higher parts of the subsided belts of the earth’s crust. Along fault lines having WNW, NW, and ONO directions (and in places bending in a steep arc), belts of melaphyres are often situated, but in places igneous rocks are absent. Dislocations were in some places accompanied by the fragmentation of broad belts of Paleozoic rocks into breccias with complete destruction of the bedding—

…such as, for example, in the lowered belt of mountains between the ridges of Maily and Konur-obo.

The area where Tarbagatai, Saur, and Urkashar join proved not to be a mountain knot, as shown on the maps: Tarbagatai does not quite reach this knot, but is cut off by the broad valley of Kotan-ashchi (apparently also a fault valley) west of the knot; the latter is caused by the junction, at the southern foot of Saur, of a more southerly ridge—namely Kodzhur, consisting of massive granite and Paleozoic rocks. This contact of the two ridges is explained by the wedging-out of two grabens: the Chilikty valley to the west and the Kobu valley to the east; but fault lines with outcrops of melaphyre pass through the knot, which, moreover, is considerably lower than both ridges. Tarbagatai, on the other hand, joins Saur to the north, by means of its northern chain—the Ters-airyk ridge, which passes into the Manrak ridge.

These tectonic features of the mountains described also determine certain features of the modern relief: thus, for example, Saur breaks off extremely steeply, without foothills, toward the western part of the Kobu valley; but farther west, in the eastern part of the Chilikty valley, its southern slope clearly forms three terraces; evidently the simple fault of the eastern part of Saur is dissected westward and becomes stepped. The middle part of the Barlyk ridge descends northward in three distinct broad steps—evidently here too there is a stepped fault; by similar steps the Manrak ridge also descends northward, and so on.

On the southern slope of Saur, in valleys opening into the Kobu valley near the kum. Matenya, I found clear traces of a formerly very considerable development of glaciers in the form of typical moraines and cirques; the glaciers reached 10–15 versts in length and extended down to the Kobu valley, whereas at present there are here only firn patches and, in places, small intermittent glaciers. In the valleys of the northern slope of Saur, which were not visited, former glaciation was evidently even more considerable, since this ridge has a short and steep southern slope and a gentle and long northern slope. In the high part of Tarbagatai (near the Khabar-asu pass) the signs of glaciation are not so clear, and in Barlyk they apparently are absent; moreover, the highest part of Barlyk—the Kert-tau ridge, where even at present snow lies almost all summer, remained off the route.

Of great interest are also observations concerning the distribution of loess, desert varnish, various forms of weathering and winnowing, especially developed in the Dzungarian Gates, as well as ancient lacustrine beach ridges there.

In conclusion, I consider it a pleasant duty to offer my sincere gratitude to the persons who contributed to the success of my journey: to the Imperial Russian consul in the city of Chuguchak, S. V. Sokolov; to the military governor of the Semipalatinsk Region, Major General Galkin; and to the vice-governor, N. F. Nitskevich. Great assistance in the work in the Tarbagatai was rendered to me by copies of the latest surveys of this range, provided to me by the kind order of Yu. A. Shmidt, head of the Omsk Military-Topographic Department.

V. A. Obruchev.