Ice drift during the 1897 Andrée balloon expedition

The indirect cause of death of the three members of the Andrée balloon expedition on White Island in early October 1897 was the ice drift during their attempted retreat after the forced landing at 82°56′N 29°52′E. They initially tried to reach Cape Flora to the southeast of their current position in the Arctic pack ice even though they could deduce from prior explorers’ experience that the expected long-term direction of the ice drift in the area would be to the southwest. However, when they finally turned towards the Seven Islands in the southwest, the ice unexpectedly began to drift in a southeasterly direction. In this paper, trigonometrical methods are used to derive more precise measures of the ice drift the expedition members actually experienced, based on their own position fixes and their own descriptions of their marches. The results confirm that they were exposed to a southwesterly ice drift, on average, during the weeks they were trying to head southeast, and to a southeasterly ice drift, on average, during the weeks they were trying to head southwest. Hence, the disastrous ending of the expedition was, at least to some extent, a result of bad luck.

Assessing the Rain estimate from the reflectivity of Nha Be Radar

This study evaluates the estimated rainfall from Nha Be radar observation according to different experimental formulas. The results show that in six estimation formulas used, the formulation of Joss's large-scale rainfall estimation and Marshall-Plamer's formulation can be used to estimate the precipitation for the single southwest monsoon with an error about 5 mm/h and usually less than the observed value. The rainfall estimation formulas by Nguyen Huong Dien is the optimum estimation for the 9 synoptic rainfall patterns: Intertropical Convergence Zone, Southwest monsoon associated with Intertropical Convergence Zone, low-pressure area, thunderstorm, disturbance in East winds, low-pressure area associated with Southwest monsoon, low-pressure troughs have a Northwestern-Southeasterly direction and other synoptic patterns with errors: 5mm/h, 9.5 mm/h, 14 mm/h, 7mm/h, 19 mm/h, 8 mm/h, 8.5 mm/h, 9.5 mm/h and 14.7 mm/h, respectively. Keywords: Radar, rain estimate.

Distribution of Urophora affinis and U. quadrifasciata, Two Flies Introduced for Biological Control of Spotted Knapweed (Centaurea maculosa) in Montana

A survey was conducted at 88 sites in Montana in 1984 and 1985 to determine the distribution of Urophora affinis Frauenfeld and U. quadrifasciata (Meigen), two seed head flies released on spotted knapweed (Centaurea maculosa Lam. # CENMA) in North America. U. affinis, released in Montana during 1973 to 1977, was found at 40 of the 88 sites. The fly was concentrated within a short radius (about 5 to 8 km) of release sites, even at sites having well-established populations. U. quadrifasciata, released in British Columbia in 1972, but not in the United States, was found at 84 sites. The data suggest that the fly entered the state in the northwest corner and dispersed in a southeasterly direction. There was a strong positive relationship between mean number of galls per seed head and percent infestation for both fly species.

Bidrag til Læsøs geologi. Lithologi, biostratigrafi og geofysik

Seven wells have been performed on the island of Læsø in the Northern Kattegat Sea in order to clarify the Quaternary stratigraphy and structure of the island. All wells have been gamme-logged and five wells have been test-pumped. In addition, geoelectrical and electromagnetic (georadar) profiles have been measured. The lithostratigraphy and biostratigraphy of the seven wells show, that the late Quaternary of Læsø can be divided into four units: 1) a lower clay unit, which biostratigraphically is nearly identical with the type-section of the marine late Eemian - early Weichselian Skærumhede Series of Vendsyssel, 2) a sandy unit, which on the basis of reworked Foraminifera is believed to be a Weichselian melt-water deposit, 3) a clayey and silty unit, which biostratigraphically and lithologically corresponds to the marine socalled Younger Yoldia Clay of Vendsyssel, and 4) Holocene, marinesands and beachridges. Unit 3 and 4 is separated by an almost horizontal abrasion surface, which in three wells is developed into a soil profile demonstrating that Læsø was elevated above sea level before the onset of the Flandrian transgressions. In other wells and outcrops the boundary between unit 3 and 4 is covered by a conglomerate of boulders derived from the underlying deposits of various age. Six of the wells have been performed within a distance of a few hundred meter enabling a structural interpretation of the· area of investigation. A correlation of the six wells demonstrate, that the pre-Holocene of Læsø is disturbed by tectonic events, since the same stratigraphical units are found at surprisingly different levels. In three wells the Younger Yoldia Clay is even missing. Thus, the pre-Holocene, including the late Weichselian, marine deposits, may be dipping as much as 4 percent towards the north or northeast. A glacio-tectonical interpretation of this structure would anticipate a new glaciation of Læsø after the deposition of the Younger Yoldia Clay. However, more likely the northward tilting of late Weichselian and older strata is related to a Fennoscandian Border Zone fault, which is crossing Læsø in northwest-southeasterly direction immediately south of the area of investigation. Normal faulting in this fault during late Weichselian and Holocene times would cause northeastwards tilting of the strata within the magnitude as actually found. Moreover, from the georadar profiles the same fault is seen also to affect the almost horizontal boundary between unit 3 and 4, since a four meter jump in the level of the abrasion surface is coincident with the above mentioned fault and an app. 3000 years old sea cliff parallel with the fault. This may explain previous observations on the topography of Læsø, which showed that Læsø is divided in 8 shore-terraces, which after their formation during the last app. 3000 years have been slightly tilted, sometimes slowly towards southwest, and sometimes comparatively rapid towards northeast. Since the general late Weichselian and Holocene isostatic recovery of Scandinavia in this area would result in gradual southwesterly tilting of ancient shore-lines, it is reasonable to suggest the southwestwards tilting of the shore-terraces to be caused by the general isostatic upheaval of Denmark, while the north or northeastwards tilting fases may be caused by normal faulting activity.

Stabilized dune ridges in northern Saskatchewan

Stabilized dune ridges occurring in northern Saskatchewan have previously been identified as variedly as "ice-crack moraines" and longitudinal dunes. Investigations of their morphological, structural, and sedimentary attributes reveal that they are, indeed, of eolian origin, but they form a particular group within the parabolic dune association, namely, the "Cree Lake type dune ridges." The ridges occur in association with other types of parabolic dunes and other eolian features, such as loess and wind-abraded glacial blocks and bedrock outcrops. The dunes and the associated eolian features were all formed by southeasterly paleowinds of uniform direction. The dune ridges developed from primary parabolic dunes of simple and composite types through the process of dune elongation. At the same time, exposed rock surfaces were abraded by the wind and loess was deposited downwind from the developing dune fields. The southeasterly direction of the paleowinds, which is almost directly opposite to the direction of the present-day winds affecting dunes in the Lake Athabasca area, was due to adiabatic air masses coming off the ice sheet from the east and affected eolian activity in quite a large region in northern Saskatchewan and Alberta. The somewhat cool and sufficiently dry adiabatic winds checked the vegetation on the dunes and in the areas around them. The development of the dune ridges came to an end when a sudden climatic change evoked the rapid stabilization of the dunes by vegetation but not before most of the ridges became partly deformed by southwesterly crosswinds resulting from the same climatic change. The period of eolian activity is estimated from the age of the local ice frontal positions to have been between 10 000 and 8800 years BP. Only one other region is known from North America, namely, the St. Lawrence Lowland in the east, where analogous eolian environment prevailed in the zone peripheral to the continental ice sheet and produced comparable eolian features.

A palaeomagnetic survey of South American rock formations - Studies on rock formations from Northeast Brazil

Devonian, Carboniferous and Xriassic formations from Piaui and Maranhao States in the northeast of Brazil have been studied and palaeomagnetic pole positions deduced. During the Devonian and Carboniferous the south pole appears to have moved away from S. America in a southeasterly direction from the vicinity of Rio de Janeiro: in the Triassic it was situated near the present position of the south pole relative to S. America. These results are in good agreement with those from other formations of the same age from other parts of the continent. Thermal cleaning has been carried out. The Devonian formations were almost completely remagnetized by the Mesozoic or Tertiary geomagnetic fields and the primary magnetization is very weak. Polar wander of 40 to 50° appears to have occurred during the time interval under investigation, i.e. M. Devonian to Triassic.

The Hogge Bridge Site and the Wylie Focus

The Lavon Dam and Reservoir, under construction by the Corps of Engineers, Department of the Army, is one of the many projects throughout the country which will soon obliterate information relating to the prehistory of North America. This particular project is located on the East Fork of the Trinity River in Collin County, Texas, 21 miles northeast of Dallas. It was scheduled for completion in January, 1952.The Trinity River is one of several major rivers flowing in a southeasterly direction across the state of Texas. It heads in four branches north and northwest of the city of Dallas and flows into Galveston Bay and thence into the Gulf of Mexico, approximately 40 miles due east of the city of Houston. The East Fork (and its principal tributary, Pilot Grove Creek) is the easternmost of the headwater branches. It rises in Grayson County and enters the main stream in southwestern Kaufman County.

The Inglewood earthquake in Southern California, June 21, 1920

summary and conclusions The earthquake of June 21, 1920 originated a short distance west of Inglewood. The maximum intensity in the epicentral area was between VIII and IX in the Rossi-Forel scale. The disturbance was due to a small displacement of the rocks on the Inglewood-Newport-San Onofre fault or fault zone which parallels the Baldwin Hills-Los Cerritos ridge on the southwest and extends in a southeasterly direction apparently as far as the San Luis Rey River. The character of the motion in the epicentral area suggests that the displacement was probably vertical. The area within which the shock was felt (eleven thousand square miles or twenty-nine thousand square kilometers) was small considering the high intensity of the shock. This probably means that the origin was close to the surface. The rapid decrease in intensity on going away from the epicenter is chiefly due to the unconsolidated character of the rock strata in this area. While the vibrations die out rapidly in passing through such materials the destructive effects are always greater than in areas similarly located with respect to the origin but which are underlain with more rigid rock. The physiography, geology, and the recent seismic history of the Los Angeles coastal plain, remind us that earthquakes are to be expected in that area from time to time. But if the inhabitants will heed nature's warnings and take proper precautions in the location and construction of buildings and other structures, such earthquakes are not likely to do much damage.

II.—Note on the Serpentine of Duporth, in St. Austell Bay, Cornwall

The Geological Survey Map of CornwalI shews, to the south of the town of St. Austell, several patches of “greenstone,” extending from near the ancient earthwork called Trethullan Castle, on the west, to the sea at St. Austell Bay in the east ; a distance of over four miles.The western end of the most extensive of these patches swells ont on the top of the hill to the north-east of St. Mewan Church, so as to cover several hundred acres (including some of the best land in the parish). This was described by Mr. J. Arthur Phillips some years since in the Philosophical Magazine. Mr. Phillips speaks of the rock as being distinctly crystalline, consisting of felspar (sometimes triclinic) ; semi-transparent yellowish-brown crystals, probably hornblende ; a green fibrous mineral also believed to be a variety of hornblende ; many black grains of oxide of iron and a few hexagonal crystals, probably apatite ; and he says the rock exhibits unmistakeable evidence of extensive alteration. Speaking of its extension eastward, he says “it extends in diminished proportions in a southeasterly direction to the sea at Duporth.”