scholarly journals Paradise from Cataclysm: Zion Canyon’s Sentinel Landslide

Geosites ◽  
2019 ◽  
Vol 1 ◽  
pp. 1-9
Author(s):  
Anna Stanczyk ◽  
Jeffrey Moore ◽  
Brendon Quirk ◽  
Jessica Castleton
Keyword(s):  
Rock Avalanche ◽  
Landslide Dam ◽  
River Flows ◽  
The North ◽  
North Fork ◽  
Virgin River ◽  
Sediment Layers ◽  
The Hill

Zion Canyon hosts millions of visitors each year, yet few are aware of the massive prehistoric landslide that played an important role in shaping the iconic landscape. South of the Sand Bench trailhead and bridge, a large hill encroaches on the canyon bottom around which the North Fork Virgin River flows. North of the bridge, Zion Canyon’s fl at bottom stretches into the distance. The hill is part of an enormous rock avalanche deposit known as the Sentinel slide that is nearly 2 miles (3.2 km) long and more than 650 feet (200 m) thick. After failure, the Sentinel rock avalanche dammed the North Fork Virgin River creating a lake (known as Sentinel Lake) which persisted for approximately 700 years (Grater, 1945; Hamilton, 1976; Castleton and others, 2016). Over the course of the lake’s lifetime, sediment settled at the bottom of the lake to create thick deposits of mud, clay, and sand. Sediment eventually fi lled in the canyon bottom behind the landslide dam, and the lake ceased to exist. Th ese sediment layers are still visible today and are responsible for the remarkably fl at fl oor of upper Zion Canyon (Grater, 1945; Hamilton, 2014; Castleton and others, 2016).

Impacts of Hikers on Aquatic Invertebrates in the North Fork of the Virgin River, Utah

2010 ◽  
Vol 55 (4) ◽  
pp. 551-557 ◽  
Author(s):  
Andrea M. Caires ◽  
Mark R. Vinson ◽  
Anne M. D. Brasher
Keyword(s):  
Aquatic Invertebrates ◽  
The North ◽  
North Fork ◽  
Virgin River

scholarly journals Virgin River Spinedace Habitat Preference Study

1987 ◽  
Vol 11 ◽  
pp. 189-190
Author(s):  
James Deacon ◽  
Anga Rebane
Keyword(s):  
River System ◽  
Early Spring ◽  
Sampling Techniques ◽  
Habitat Conditions ◽  
Winter Habitat ◽  
The North ◽  
Beaver Dam ◽  
North Fork ◽  
Virgin River ◽  
Preference Study

Thus far in the study, 4 species of endemic fishes and 2 introduced trout species have been collected, measured for total length, and in some cases, weighed, and then released. Sampling has been accomplished by electroshocking on 6, 7, 8, and 9 July, 1987, at 4 sites on the East and North Forks of the Virgin River, as well as 1 site on the Santa Clara River, and 1 site on Moody Wash near Mogatsu Creek, a tributary of the Santa Clara River. Seining, measuring, and releasing was done on 3, 4, and 20 September, 4 and 10 October, and on 9 and 10 January, 1988, at five sites on the East and North Forks of the Virgin River. Electroshocking was used on 9 January, 1988 at one of the North Fork sites, utilizing a backpack electroshocker unit borrowed from Donna Withers, of the Nevada Department of Wildlife. On 24, 29, and 30 August, fish were surveyed by seining or dip netting at Lytle Ranch, on Beaver Dam Wash, a tributary of the Virgin River, for purposes of determining favorable habitat conditions under a different regime. Electroshocking was determined to be limited in use in the Virgin River system, due to the frequent turbidity of the water, and the depth of the pools. In winter we have not collected substantial numbers of any species, with either electroshocking or seining techniques. It is possible that the fish are located in places unaccessible to our sampling techniques, or possibly they have undertaken significant migration to other locations, most likely towards the warmer waters of lower elevations. Mass mortality can be ruled out due to the fact that all fish species have been observed to reappear in early spring. We need to revise our sampling techniques, and are working on a variety of different procedures to be able to collect fish in winter, or find out where they live. The limitations of the winter habitat may prove to be an important factor in the continued success of the spinedace in the Virgin River in Zion. The borrowed electroshocking equipment seems marginally successful in sampling fishes in the highly conductive water of the Virgin. A more powerful unit needs to be procured. When the water is clear, shocking works well because the fish can be visualized and netted while immobilized by the shocker, but the frequent turbidity of the water would make any fish not surfacing impossible to see and catch, even though it was immobilized.

An Iron Age A site on the Chilterns

1951 ◽  
Vol 31 (3-4) ◽  
pp. 132-148 ◽  
Author(s):  
K. M. Richardson ◽  
Alison Young
Keyword(s):  
Water Supply ◽  
Iron Age ◽  
The West ◽  
North West ◽  
The North ◽  
Roman Villa ◽  
Adjoining Area ◽  
Cursory Examination ◽  
A Site ◽  
The Hill

In 1946 a visit to the barrow, which lies on the edge of the western scarp of Chinnor Common, and a cursory examination of the adjoining area, cultivated during the war, resulted in finds of pottery and other objects indicating Iron Age occupation. The site lies on the saddleback of a Chiltern headland, at a height of about 800 ft. O.D. Two hollow ways traverse the western scarp, giving access to the area from the Upper Icknield Way, which contours the foot of the hill, then drops to cross the valley, passing some 600 yards to the north of the Iron Age site of Lodge Hill, Bledlow, and rising again continues northwards under Pulpit Hill camp and the Ellesborough Iron Age pits below Coombe Hill. The outlook across the Oxford plain to the west is extensive, embracing the hill-fort of Sinodun, clearly visible some fourteen miles distant on the farther bank of the Thames. The hollow way at the north-west end of the site leads down to a group of ‘rises’ hard by the remains of a Roman villa, and these springs are, at the present day, the nearest water-supply to the site.

Art. VII.—Notes on Persian Belúchistán. From the Persian of Mirza Mehdy Khán. Published Teheran, July, 1875

1876 ◽  
Vol 9 (1) ◽  
pp. 147-154
Author(s):  
A. H. Schindler
Keyword(s):  
Indian Ocean ◽  
Temperate Climate ◽  
The South ◽  
The West ◽  
The North ◽  
The People ◽  
The Indian Ocean ◽  
The Hill ◽  
Cool Climate

The part of Belúchistán now under Persian rule is bounded upon the north by Seistán, upon the east by Panjgúr and Kej, upon the south by the Indian Ocean, and upon the west by Núrámshír, Rúdbár, and the Báshákerd mountains.This country enjoys a variety of climates; almost unbearable heat exists on the Mekrán coast, we find a temperate climate on the hill slopes and on the slightly raised plains as at Duzek and Bampúr, and a cool climate in the mountainous districts Serhad and Bazmán. The heat at Jálq is said to be so intense in summer that the gazelles lie down exhausted in the plains, and let themselves be taken by the people without any trouble.

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