Geology topics

Karl W. Stauffer

Publications and source records attributed to Karl W. Stauffer.

7 recordsLinked to original sources

USGS1975

Geology of the Khyber Pass, Khyber Agency, Pakistan

The defile of the Khyber Pass is cut in the massive gray recrystallized Khyber Limestone whose thickness exceeds 3,000 feet. Although no fossils have been found in the immediate vicinity of the pass, assemblages collected at the end of the last century from 5 miles south of the pass, and recently collected fossils from Afghanistan, suggest strongly that the limestone is Carboniferous to Permian and perhaps Jurassic in age. The basal contact of the Khyber Limestone in places appears to be conformable upon the quartzites and tuffs of the Ali Masjid Formation; elsewhere it is probably an unconformity or a fault, especially where the limestone lies directly on the Ordovician to Carboniferous Landi Kotal Slate. The Ali Masjid Formation overlies the Shagai Limestone, which, in turn, rests in fault contact on the Landi Kotal Slate. Structurally the area is characterized by at least four major, roughly east-west trending thrust or reverse faults, along which relatively older rocks have moved southward over younger rocks. A north-northeast-trending system of alternating anticlines and synclines has been superimposed on the earlier structures. Elevated terraces and alluvial valleys suggest a very recent uplift of about 600 to 1,000 feet.

Khyber Pass, Khyber Agency↗

USGS1975

Geology of the Gilgit-Hispar area, Gilgit Agency, Pakistan

The Gilgit-Hispar area contains a large variety of igneous and metamorphic rocks, which have been grouped into seven general lithologic units, five composed largely of metamorphic rocks and two of intrusive rocks. The metamorphic units consist of probable correlatives of the Precambrian(?) Salkhala Series; the upper Paleozoic, slightly metamorphosed schists, quartzites, and calcareous rocks of the Chalt Schist; the higher metamorphosed (garnet and staurolite grades) schists, gneisses, and marbles of the Baltit Group; the Pasu Slate; and the Triassic(?) and older(?) greenstone complex consisting in large part of metavolcanic rocks. The metamorphism of the area is due at least in part to the intrusions of two huge silicic to intermediate batholiths of Cretaceous to Tertiary age composed largely of biotite granodiorite. The structural grain is west-northwest throughout the area and represents a part of the structural pattern whose focus is the Hazara-Kashmir syntaxial bend. Although steep faults and isoclinal folds are present, no large thrust faults were seen. The area apparently is structurally less complicated than comparable parts of the Hindu Kush mountains farther west in Chitral State. Deeply incised streams and elevated terraces indicate very recent uplift of considerable magnitude. Although traces of potential ore minerals are common in the Gilgit-Hispar area, deposits of possible commercial value were not seen. Heavy-mineral samples of stream sands contain fairly high concentration of scheelite. The radioactivity of the stream sands is in large part due to the thorium and uranium content of zircon. Radiometric traverses showed slightly higher radioactivity over gneisses and quartzites than over other rocks, but no unusually high values were recorded.

Open-File Report↗

USGS1975

Heavy mineral prospecting in Pakistan

Heavy-mineral prospecting is a method of tracing potential ore minerals to their source by systematically examining the heavy minerals of stream sands. The heavy minerals are partially concentrated in the field by panning. In the laboratory the heavy minerals are further concentrated by floating off the quartz and feldspar in a heavy liquid, such as bromoform, having a specific gravity of 2.89. Magnetite is separated magnetically and scheelite is identified under short-wave ultraviolet light. To obtain quantitative results on the minerals present, the sample is reduced by coning and quartering, mounted on a slide in oil, and a count of a minimum of 250 grains made. The chi square test applied to the splitting and counting techniques shows them to be statistically valid. The properties of some heavy minerals most useful for their rapid identification are listed. Methods here described are those utilizing a minimum of field and laboratory equipment and may be appropriate for application in many areas of the world.

Open-File Report↗

USGS1975

Heavy minerals in stream sands of the southern Hazara District, Pakistan

The areal distribution of heavy minerals in 99 samples from stream sands in the southern Hazara District, West Pakistan, indicates that the metamorphic grade of the rocks in the area increases toward the northwest. Minerals of potential economic value in the heavy-mineral samples include scheelite from the Oghi-Batgram-Battal area and hematite from the Galdanian area. The total weight of magnetite sand grains transported down the Indus River past Darband is calculated to be about 200,000 tons per year, a quantity which may be of economic value. Radioactive minerals are not present in any of the samples in sufficient quantity to be of economic importance.

Hazara District↗

USGS1975

Reconnaissance geology of the Central Mastuj Valley, Chitral State, Pakistan

The Mastuj Valley in Chitral State is a part of the Hindu Kush Range, and is one of the structurally most complicated areas in northern Pakistan. Sedimentary rocks ranging from at least Middle Devonian to Cretaceous, and perhaps Early Tertiary age lie between ridge-forming granodiorite intrusions and are cut by thrust faults. The thrust planes dip 10? to 40? to the north- west. Movement of the upper thrust plates has been toward the southeast relative to the lower blocks. If this area is structurally typical of the Hindu-Kush and Karakoram Ranges, then these mountains are much more tectonically disturbed than previously recorded, and suggest compression on a scale compatible with the hypothesis that the Himalayan, Karakoram, and Hindu Kush Ranges form part of a continental collision zone. The thrust faults outline two plates consisting of distinctive sedimentary rocks. The lower thrust plate is about 3,000 feet thick and consists of the isoclinally folded Upper Cretaceous to perhaps lower Tertiary Reshun Formation. It has overridden the Paleozoic metasedimentary rocks of the Chitral Slate unit. This thrust plate is, in turn, overridden by an 8,000-foot thick sequence consisting largely of Devonian to Carboniferous limestones and quartzites. A key factor in the tectonic processes has been the relatively soft and plastic lithology of the siltstone layers in the Reshun Formation which have acted as lubricants along the principal thrust faults, where they are commonly found today as fault slices and smears. The stratigraphic sequence, in the central Mastuj Valley was tentatively divided into 9 mapped units. The fossiliferous shales and carbonates of the recently defined Shogram Formation and the clastlcs of the Reshun Formation have been fitted into a sequence of sedimentary rocks that has a total thick- ness of at least 13,000 feet and ranges in age from Devonian to Neogene. Minerals of potential economic significance include antimony sulfides which have been mined elsewhere in Chitral, the tungstate, scheelite, which occurs in relatively high concentrations in heavy-mineral fractions of stream sands, and an iron-rich lateritic rock.

Open-File Report↗

USGS1969

Devonian laterite in Chitral state, West Pakistan

A Devonian laterite has recently been discovered near Reshun in the Mastuj valley of Chitral State, West Pakistan. It is believed to be the fourth recorded Paleozoic laterite in the world. The laterite is entirely within a thick carbonate of the Shogram Formation of Upper Devonian (Frasnian) age. A chemical analysis of the laterite shows the principal constitutents to be: Al 2 O 3 35.5%, SiO 2 , 21.7% Fe 2 O 3 16.0%, FeO 10.3%, TiO 2 , 3.5% CaO 0.97%, and MgO 0.70%. Minerals determined by X-ray analysis include hematite, boehmite, diaspore, anatase, rutile, kaolinite, pyrophyllite and what is probably chamosite.

Chitral↗

USGS1968

Silurian-devonian reef complex near Nowshera, West Pakistan

The first Paleozoic reef belt on the Indo-Pakistan subcontinent has recently been recognized near the town of Nowshera (lat 34°00′ N., long 72°00′ E.) in northern West Pakistan. It consists of nine separate hills aligned in a 15-mile-long, east-west band rising out of the Peshawar alluvial plain. Each hill is composed of one or more reef cores whose thicknesses range from less than 100 feet to more than 700 feet. The reef cores are separated by relatively unfossiliferous carbonate rocks thinner than the reefs. The reef belt contains a fauna entirely new to Pakistan that has been dated as Early Devonian to to Late Silurian (Ludlovian to Gedinnian). The reef carbonates are the first sediments of possible Silurian age found anywhere in the country and the southernmost Devonian deposits in West Pakistan. Individual reef cores consist of faunal zones or layers that indicate a gradual growth of the reef mass from relatively quiet water upward into rough water. The presence of these reefs and correlative fossiliferous carbonate sediments in the Peshawar area suggests that in Silurian and Devonian times much of northern West Pakistan was covered by warm, shallow seas bordered by reefs or containing reef platforms. The association of these Paleozoic reefs with extensive deposits of fetid black limestones and porous dolomites may indicate economic potential for the accumulation of oil.

Town of Nowshera in northern West Pakistan↗