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At least 307 records · Page 17Linked to original sources
USGS1986

Late Neogene and Quaternary coarse-fraction and carbonate stratigraphies for Site 586 on Ontong-Java Plateau and Site 591 on Lord Howe Rise

Carbonate oozes recovered by hydraulic piston coring at DSDP Site 586 on Ontong-Java Plateau and Site 591 on Lord Howe Rise have carbonate contents that are consistently higher than 90% with only minor variations. Consequently, paleoceanographic signals were not recorded in detail in the carbonate contents. However, mass accumulation rates of carbonate increased in the late Miocene to mid-Pliocene, reflecting an increase in productivity, then abruptly decreased from mid-Pliocene to the present. Variations in relative abundances of coarse material (foraminifers) and fine material (mostly calcareous nannofossils) do reflect histories of current winnowing and biogenic productivity at the two sites. The late Miocene from 10.5 to 6.5 m.y. ago was a time of relatively constant, quiet, pelagic sedimentation with typical southwest Pacific sedimentation rates of 20-25 m/m.y. The average coarse-fraction abundances are always higher at Site 586 than at Site 591, which reflects winnowing at Site 586. These conditions were interrupted between 6.5 to 4.0 m.y. ago when increased upwelling at the Subtropical Divergence and the Equatorial Divergence produced greater productivity of calcareous planktonic organisms. The increased productivity is suggested by large increases in both fineand coarse-fraction material and constant ratios of foraminifers to nannofossils. The maximum of productivity was about 4.0 m.y. ago. This period of increased upwelling is coincident with the inferred development of the West Antarctic ice sheet. The high productivity was followed by an abrupt increase in winnowing about 2.5 m.y. ago at Site 591, but not until about 2.0 m.y. ago at Site 586. By 2.0 m.y. ago in the late Pliocene, quiet, pelagic sedimentation conditions prevailed, similar to those of the late Miocene. The last 0.7 m.y. has been a period of relatively intense winnowing on Lord Howe Rise but not on Ontong-Java Plateau. The coarse-fraction data have both long- and short-period fluctuations. Long-period fluctuations at Site 591 average about 850 × 103 yr./cycle and those at Site 586 average 430 × 103 yr./cycle. The highest amplitudes are found in the Pliocene and Quaternary sections. The short-period fluctuations range from 100 to 48 × 103 yr./cycle at Site 586 and from 250 to 33 × 103 yr./cycle at Site 591. The effects of local fluctuations of productivity and winnowing have modified the primary orbital forcing signals at these two sites to yield complex paleoceanographic records

Initial Reports of the D.S.D.P.↗
USGS1946

Stratigraphy and structure of the area of the Killik, Chandler, Anaktuvuk, and Colville Rivers, Alaska

This report deals with results of field and laboratory studies carried out to May 1946 by the Geological Survey, largely as part of the Navy Department's program of petroleum investigations in northern Alaska. The immediate purpose of the work has been to collect and interpret stratigraphic and structural data pertinent to drilling in the Umiat area. Field studies were made during the summers of 1944 and 1945 in the drainage areas of the Colville, Killik, Chandler, and. Anaktuvuk Rivers (fig. 1). Paleontologic and microlithologic studies, together with stratigrahica1 and structural analysis of the areas, were carried out in the petroleum laboratory in Fairbanks. This work led. to preparation of a preliminary report submitted. in December, 1945. Additional detailed studies, in the Survey laboratories and offices in Washington, D. C., have resulted in some modification of earlier conclusions and changes in illustrations. The changes are minor and have no significant bearing on drilling in the Umiat area. The present report is accompanied. by revised conies of figures 1, 2, 3 (sheet 1) and. 5. These illustrations should be substituted for the comparable figures of the preliminary report. Figures 3 (sheet 2), 4, and. 6 of the earlier report stand unchanged and should, be added to the illustrations accompanying the present report. It is believed that work to date has revealed the general geologic picture of the area and. that the sequence of Upper Cretaceous rocks is established. The section of rocks in Umiat Test No. 1 has been approximately located within the sequence. This report, and the work on which it is based was done under the supervision of George O. Gates, who has contributed. much to the study.

Alaska↗
USGS1950

Stratigraphy and structure of the Okpikruak and Kiruktagiak Rivers area, Alaska

Navy Oil Unit Party 4, during the summer field season of 1949, examined the surface geology of the area of the Okpikruak and Kiruktagiak Rivers. The party consisted of six men: two geologists, two field assistants, a weasel mechanic, and a cook. Three weasels were used for transportation in the field. The area covered is bounded on the west by the Okpikruak River, on the east by the Chandler River, and on the south by the north front of the Brooks Range. Tuktu Bluff on the Chandler River and its westward extension forms the northern boundary. The area is drained by the Chandler, Kiruktagiak, Ayiyak, Okokmilaga, and Okpikruak Rivers. The objectives of this summer's work was the geologic mapping and stratigraphic study of the rocks that crop out in this area. All outcrops were visited and the geology was plotted on vertical and trimetrogon oblique aerial photographs. Altitudes were established by an altimeter traverse. Parts of this area had been investigated previously by members of the Navy Oil Unit. During the summer of 1945 George Gryc, E. J. Webber, and Karl Stefansson visited outcrops along the. Chandler and Kiruktagiak Rivers and in the vicinity of Castle Mountain. In the same year L. A. Warner and C. E. Kirschner examined outcrops along the Okpikruak River in conjunction with their survey of the Klink and Colville Rivers. R. L. Detterman included detailed stratigraphic studies of cutbanks near the confluence of the Kiruktagiak and Chandler Rivers in his geological mapping of the lower Chandler during the summer of 1948.

Alaska↗
USGS1950

Stratigraphy and structure of the area of the upper Meade River, Alaska

The stratigraphic evidence in the upper Meade River area includes zones B to D of the Nanushuk group (Cretaceous). Zones B and C are not differentiated in mapping and description. South of the Meade River 2,100 feet of zones B-C and 1,500 feet of zone D are exposed. North of the fault zone along the Meade River, the only rocks present, estimated not over 1,000 feet thick, are zone D beds which may be at least in part younger than the zone D rocks south of the Meade River. Sands which barely meet the minimum requirements for potential reservoir beds are present in both zones. South of the Meade River the Kigalik anticline and the Falcon Creek anticline, both sharp-crested folds, trend east. The intervening synclines are broad with low dips on the flanks. Along the Meade River the major structure is a zone of reverse faults, about three-fourths of a mile wide, which brings rocks of zones B-C on the south opposite rocks of zone D on the north. Minimum displacement in this zone is 1,000 feet at longitude 157° 50'W. and 300 feet near the gas-seep lake. North of the fault zone, the Meade River anticline is a rather low fold, so poorly exposed that closure cannot be detected by surface geologic methods.

Alaska↗
USGS1950

Review of the stratigraphy and structure of the Gubik anticline

At the direction of Ralph L. Miller, a special study was made of part of the Gubik anticline east of the Colville River. The purpose of this study was two fold; first, the examine the field evidence bearing on east plunge, second, to attempt to establish the continuity of the anticlinal axis from the Colville River to the Anaktuvuk River. The results of this study and a summary of results of the study of part of the anticline west of the Colville River by Stefansson and Thurrell 1/ are presented below.

Alaska↗
USGS1950

Stratigraphy and structure of the Aupuk anticline

In addition to conducting an examination of the surface geology in the Southern Foothills province between the Killik River and east fork of the Etivluk River, Navy Oil Unit Party No. 5 was requested to map the Aupuk anticline during the 1950 field season, for the purpose of evaluating the petroleum possibilities thereof from the standpoints of favorable statigraphy and possible structural closure. Field mapping of the Aupuk anticline began on August 1, and about 1 month was devoted to the study. Party personnel consisted of G. Donald Eberlein and Charles D. Reynolds, geologists, W. L. D'Olier and W. D. Carter, field assistants, Richard Olson, camp cook, and Max H. Davis, weasel mechanic. Robort M. Chapman, geologist, visited the party for 1 week early in August to help start the work and shared, with Eberlein, the responsibilities associated with the final compilation of this report. Three weasels were used for daily transportation to the field and for moving camp. A 10-foot Link boat equipped with 5 hp. outboard motor was used to cross the Colville River. As field work progressed from west to east it became apparent that the camp equipment and weasels would have to be gotten across the Colville River if field work was to be completed by early September. This crossing was effected without incident at a point approximately 10 miles below the confluence of the Kurupa and Colville Rivers on August 26. The party reached Umiat on September 5.

Alaska↗
USGS1947

Stratigraphy and structure of the area of Maybe Creek

During the summer of 1946 the United States Geological Survey continued its program of stratigraphic and structural investigations in Naval Petroleum Reserve No. 4, northern Alaska. This report summarizes the results of work in the area of Maybe Creek (see inset, fig. 1). The area studied is southwest of Umiat and includes about 500 square miles lying generally between the headwaters and mouth of Maybe Creek. Structural data covering approximately 250 square miles of this area has been compiled from aerial photographic studies. The area is bordered generally on the north by the lake country and on the west by the Ikpikpuk River. Most of the area is north of Maybe Creek except for that part extending for 6 miles south of Maybe Creek between longitudes 153° 30' W. and 154° 20' W. The latitude of Maybe Creek is about 69° 15' N. The stream flows generally westward and at longitude 154° 40' W. unites with the eastward-flowing Kigalik River to form the Ikpikpuk River, which has a northerly course across the Arctic Slope to the ocean.

Alaska↗
USGS1951

Stratigraphy and structure of the upper Siksikpuk - Nanushuk Rivers area

Structural and stratigraphic studies of tha rocks in the Siksikpuk and Nanushuk Rivers area were conducted by Navy Oil Unit party 2 during the summer field season of 1950. The field party consisted of two geologists, two field assistants, a cook, and a weasel mechanic. Three weasels were used for transportation of equipment and personnel. The area examined covers approximately 1,000 square miles of the Arctic Foothills province and lies between the Itkillik River on the east and the Chandler River on the west. The area is drained by the Itkillik, Nanushuk, Anaktuvuk, Siksikpuk, and Chandler Rivers. The mapped area adjoins the Okpikruak and Kiruktagiak Rivers area 1/ to the west. The primary objective of the geologic work in this area was detailed stratigraphic study of pre-Nanushuk group rocks in the Southern Foothills belt as a supplement to the Work begun in the Okpikruak and Kiruktagiak Rivers area in 1949. A secondary objective was areal mapping and structural studies for the purpose of delimiting structures favorable for drilling tests of the Lisburne limestone. Parts of this area had been reconnoitered by members of the U. S. Geological Survey in previous years. In 1901 F. C. Schrader traversed the Anaktuvuk River, In 1945 R. E. Fellows, R. M. Chapman, and C. T. Bressler visited outcrops along the northern margin of the area in the vicinity of the Anaktuvuk River and Kanayut Creek. E. J. Webber and R. L. Detterman examined a few of the cutbanks along the Nanushuk River in 1947; and in 1949 A. L. Bowsher, Sr., and J. T. Dutro mapped an outlier of Lisburne limestone north of Nanushuk Lake.

Alaska↗
USGS1951

Stratigraphy and structure of the southern foothills section between the Etivluk and Kiligwa Rivers

The part of the Southern Foothill section, Arctic foothills province, that lies beteween the Etivluk and Kiligwa Rivers was investigated by Navy Oil Unit party 6 during the 1950 field season, A belt about 16 miles wide and 60 miles long (approximately 800 square miles) was mapped in considerable detail (see index map, pl. 1). The mapped area is in the west-central part of the Arctic Foothills province, wholly within the boundaries of Naval Petroleum Reserve No. 4. Major drainage consists of the middle reaches of the Etivluk, Ipnavik, Kuna, and Kiligwa Rivers. Principal objectives of the party, using previous geologic studies in. the Okpikruak-Kiruktagiak Rivers area 1/ ao an initial working base, were stratigraphic and structural studies of the outcrops in the interstream areas. In view of the former interest in possible Lisburne limestone plays, the Lisburne Ridge west of the Etivluk River and the northward nosing of the Triassic complex between the Ipnavik and Kuna Rivers were designated as areas for particular emphasis. The party included six men: two geologists; two field assistants, a cook, and a weasel mechanic. Three weasels were available for transportation; two of which were maintained in operating condition for daily field use. As many exposures as were pertinent or accessible were examined. Vertical photographs were used for plotting data and for areal control; relative vertical control was established with altimeters, The effective working radius from base camp as increased from 8 miles to 20 miles by making frequent 2- or 3-day spike trips.

Alaska↗