Microbiotic crusts as biomarkers for surface stability and wetness duration in the Negev Desert
Microbiotic crusts play an important role in arid and semi-arid regions. In an attempt to assess the main factors that may determine their growth, measurements of the amount of fines (silt and clay), rain, moisture content, wetness duration and wind
erosion and deposition were carried out along a 12 station transect within a partially crusted dune field in the western Negev Desert and compared to the crust cover and chlorophyll content. Results and discussion. Owing to the strong positive relationship
between daylight wetness duration and the crust's chlorophyll content, the crust may serve as a useful biomarker for the quantification of surface wetness duration.
[b1] Inst. of Earth Sciences, Hebrew Univ., Jerusalem, Israel
Investigation of coupling between surface processes and induced flow in the lower continental crust as a cause of intraplate seismicity
California ; Earth surface processes ; Erosion rate ; Global change ; Human impact ; Japan ; Natural hazards ; Plate tectonics ; Seismicity ; South Carolina ; United States of America
On the basis of the rheological knowledge gained, it is suggested that intraplate seismicity can also be caused by coupling between surface processes and flow in the lower continental crust. This view is shown to be a natural consequence
of the modern idea that isostatic equilibrium is maintained by flow in the weak lower crust in response to erosion and sedimentation. It is supported by a general correlation between the vigour of surface processes and rates of intraplate seismicity
Soil crusting impact on soil organic carbon losses by water erosion
This study was conducted in Tougou Catchment (northwest of Burkina Faso), characterized by sandy soils with varying types of surface crusts. The 4 different crust types studied were : structural crusts (STRU), which were found under cultivated soils
, which were plowed annually; perennial desiccation crusts (DES), gravel (GRAV) and erosion (ERO) crusts, generally found in the degraded semi-arid savannas. Water and sediment samples were collected from the runoff plots after every rainfall event (n = 10
) of the 2011 rainy season. The sediment samples were analyzed for organic carbon (OCsed), while the water samples were examined for dissolved organic carbon (DOC). This study pointed out a significant relationship between soils crusting on SOC erosion
. It showed that the formation of loose and sandy crusts provides greater SOC protection from water erosion, which in turn may improve SOC stabilization and associated soil functions, such as soil fertility, water-holding capacity and sequestration
[b4] IRD-BIOEMCO c/o School of Agricultural, Earth and Environmental Sciences, Univ. KwaZul-Natalu, Scottsville, Afrique du Sud
A new concept of neotectonics within the framework of geotectonics is discussed in this article. The A. applied the principles of synergetics and periodicity. Neotectonics can be regarded as a discipline studying, above all, the Earth'scrust
The summary of knowledge on the evolution of the Himalayan relief and its generalisation on the basis of comparison with other mobil zones of the Earth'scrust. (MS).
According to v. Bubnoff, the varied substructure is the cause for the different mobility behaviour. The types of crustal structure correspond to original arrangements of formation of the earth'scrust. As an original arrangement, in addition
to shields, the type of the shelf crust exists, as illustrated by Central and Western Europe. The geosynclinal, tectogenetic and magmatic development conditioned by the drift in this shelf crust region is described in outline. The geotectonic events
Wind erosion on the north-eastern Tibetan Plateau : constraints from OSL and U-Th dating of playa salt crust in the Qaidam Basin
Aeolian features ; Aeolian transport ; Arid area ; China ; Dating ; Geomorphology ; Isotope dating ; Optically stimulated luminescence ; Playa ; Salt crust ; Sedimentary basin ; Tibet ; Wind erosion
The aim of this paper is to constrain the timing of the formation of salt crusts and playas in the Qaidam Basin. Optically stimulated luminescence (OSL) and U-series dating from a pit section and from the top of a deep drill core, together
with results from magnetostratigraphy and a climate proxy record correlated to the marine oxygen isotope record, are used here to determine the age of the playa plains and suggest that the salt crusts have an age of c. 0.1 Ma. This young age and the wide
distribution of resistant thick salt crusts of the playa plains indicate a much lower degree of wind erosion than previously suggested. The crusts protect the surface from significant surface erosion (including sediment exhumation and unloading) and whilst some
[b2] State Key Lab. of Loess and Quaternary Geology, Inst. of Earth Environment, CAS, Xi'an, Chine
Dust fall and biological soil crust distribution as indicators of the aeolian environment in China's Shapotou railway protective system
Spatial and temporal distributions of dust fall along with the spatial variation of the biological crust were measured along a cross-section in China's Shapotou railway protective system. The variation of the aeolian environment was evident from
the spatial variation of near-surface wind flow and both grain size and accumulation rate of dust fall. The surface conditions along the cross-section were characterized by crust type, crust thickness, and ground (0–5 cm) compaction. The distribution of dust
fall and crust indicated the intensity of aeolian activity and the stability of the aeolian environment. Further improvement of the aeolian environment by natural processes or by human construction would promote additional dust fall and accelerate
the development of the crust.
[b1] State Key Lab. of Earth Surface Processes and Resource Ecology, Normal Univ., Beijing, Chine
The effects of heavy winter rains and rare summer rains on biological soil crusts in the Negev Desert
Biological soil crusts (BSCs) abound in the Hallamish dune field in the western Negev Desert, Israel. The aim of this paper is to examine crust responses to winter and summer rains, focusing particularly on its biomass components, chlorophyll
of the BSCs increase 2–3-fold following winter rains; much higher species composition was monitored at the BSC during the winter; summer rain substantially deceased the chlorophyll content of the crusts; summer rains may alter species composition and biomass
[b1] Inst. of Earth Sciences, Hebrew Univ., Jerusalem, Israel
The contribution discusses problems of the evolutional history of the earth'scrust, such as cycles, stages and direction of geological processes, which are influencing the regularities of endogenous ore formation. The A. examines these regularities
The mechanical behaviour of rock under crustal and mantle conditions in The Earth: its origin, structure and evolution.
A brief survey is given of the types of mechanical behaviour that might be expected in the crust and mantle in the light of recent experimental studies. Emphasis is placed on the variety of possible behaviour and the difficulties that arise out
of the earth's relief or have changed the letter| 2. denote that part of geomorphology which covers the formation of surface forms through crust movements (with tectonic geomorphology as a synonym). Thus, the term morphotectonics is similar to the term active
The present paper is an attempt to define the term morphotectonics. In contrast to the term structural tectonics, this term should: 1. comprise all kinds of crust movements that have resulted into the formation of both major and minor forms
morphostructure used in Soviet geomorphology rather than neotectonics because the latter is confined to those kinds of crust movements that result into surface forms and also extends beyond the Neogene to the Paleogene and the early Mesozoics. The science
of morphotectonics should investigate and categorize all surface forms brought about by crust movements. In addition, the movements themselves should be included in the research and be seen in connection with and integrated into geological and geophysical studies
Infiltration through three contrasting biological soil crusts in patterned landscapes in the Negev, Israel
The AA. examine the role of soil crusts in infiltration processes in 3 contrasting environments in the Northern, Central, and Central-Western Negev. The 3 crust types are : a dune sand supporting an almost continuous thin cyanobacterial and moss
crust, a predominantly physically (depositional) crusted loess soil sparsely colonised by cyanobacterial filaments, and a loamy hillslope soil supporting a well-developed crust colonised by cyanobacteria lichens, and some mosses. The AA. examine
the influence of crusts on water flow, and infer likely effects of crusts and their removal on ecological processes in landscapes characterised by a patchy distribution of resources.