Endogenic Forces Research Articles

Size Distributions Reveal Regime Transition of Lake Systems Under Different Dominant Driving Forces

AbstractPower law size distribution is found to associate with fractal, self‐organized behaviors and patterns of complex systems. Such distribution also emerges from natural lakes, with potentially important links to the dynamics of lake systems. But the driving mechanism that generates and shapes this feature in lake systems remains unclear. Moreover, the power law itself was found inadequate for fully describing the size distribution of lakes, due to deviations at the two ends of size range. Based on observed and simulated lakes in China's 11 hydro‐climatic zones, we established a conceptual model for lake systems, which covers the whole size range of lake size distribution and reveals the underlying driving mechanism. The full lake size distribution is composed of three components, with three phases featured by exponential, stretched‐exponential and power law distribution. The three phases represent system states with successively increasing degrees of heterogeneity and orderliness, and more importantly, indicate the dominance of exogenic and endogenic forces, respectively. As the dominant driving force changes from endogenic to exogenic, a phase transition occurs with lake size distribution shifted from power law to stretched‐exponential and further to exponential distribution. Apart from compressing the power law phase, exogenic force also increases its scaling exponent, driving the corresponding lake size power spectrum into the regime of “blue noise.” During this process, the autocorrelation function of the lake system diverges with a possibility of going to infinity, indicating the loss of system resilience.

Response of Surface Erosion to Crustal Shortening and its Influence on Tectonic Evolution in Fold‐and‐Thrust Belts: Implications From Sandbox Modeling on Tectonic Geomorphology

AbstractStructural deformation affects surface processes and the consequent distribution of tectonic stress and structural deformation patterns via crustal isostasy. The associated processes and mechanisms are widely concerned topics in tectonic geomorphology. In this study, we discuss the interaction between tectonic deformation and surface processes in fold‐and‐thrust belts by sandbox experimental modeling. The tectonic deformation patterns under different conditions are studied, including the occurrence of detachment and the different crustal shortening rates. Furthermore, we discussed the influence of surface erosion and sedimentation on the spatial distribution, morphology, amplitude, and process of tectonic deformation. The results show that the occurrence of plastic detachment links the interaction of surface erosion and tectonics such as deformation patterns. Thin‐skinned structures develop when plastic detachment occurs, thus amplifying surface processes. In turn, the erosion and deposition affect the position and morphology of new structures as well as the lateral propagation and connection of isolated structures. Different shortening rates lead to different propagation distances and structure arrangements. These different tectonic conditions result in diverse drainage evolution and the specific processes of surface erosion and deposition. In general, structural development is controlled by both endogenic forces and surface erosion and deposition processes. The physical properties of detachments and crustal shortening rates play an important role in linking deep tectonic activity and surface processes. These results are comparable to natural examples, such as the fold‐and‐thrust belts along the Tianshan Mountains, thus providing new clues for understanding the mechanism of the interaction between endogenic tectonic activity and surface processes.

Occator crater in color at highest spatial resolution

The geology of the outstanding crater Occator on Ceres has been studied by combining highest resolution color images and other information from the DAWN mission. Thus, surface and sub-surface layers and geologic processes can be understood and interpreted in a consistent manner. In order to achieve this, morphometry, absolute surface unit ages, color, and the distribution of foci of activity were the key data. These data show that the ascent of brine from reservoir(s) at depth and deposition of its salts on the surface persisted much longer than initially thought possible as an immediate result of the primary impact. The youngest depositional processes of bright material occurred less than 2 Ma ago. Also, the bright Cerealia and Vinalia Faculae are not the only traces of this activity; updoming is present on the southwestern crater floor. Faculae coincide with fractures and vents and indicate complex mechanisms of the deposition of bright carbonate-rich material. Due to the large age difference between the Occator impact itself, modeled cooling times of heated crater material, and the recent activity at the faculae we conclude that endogenic forces were lately acting. The distribution and thickness of surface and sub-surface brine layers are far from homogeneous in the upper crust beneath Occator. Further evidence regarding the distribution of materials has been derived from the distribution of the ejecta and the transition of ejecta to background material outside the crater.

Vortex Theory and Earth Dynamics

Morphological evidence in active tectonic areas consisting of subcircular shapes suggests that these geometries may originate from alternative mechanisms to those described by translational dynamics of complex faults. The mechanics behind endogenic forces, in particular convection currents, hasn't been completely explained. Differing in density from upward flows developing in atmosphere and in water, magma upwelling from the mantle can trigger endogenic vortexes in particular conditions and due to Coriolis Force. At their onset and ascent phase, vortexes apply lateral forces as result of rotation, open their way toward the surface and over time stabilize the channel. Opposite to a rising linear flow which compacts overlying materials impeding their surge, vortex flows unload the materials externally and compact them on the lateral surface of the channel, thus making it more regular and stable. Torsional movements on the surface associated to vulcanites, lateral ramps and subcircular elevations, can be observed. Other phenomena that may be consequence of vortex dynamics are the volcanic cones showing pseudo-rotations in the morphologies surrounding the crater. In this study we suggest a modeling for a vortex theory which may explain the Earth dynamics in terms of spiraling movement and magma upwelling stabilizing over time.

Topographic constraints on the origin of the equatorial ridge on Iapetus

Saturn’s moon Iapetus has an equatorial ridge system, which may be as high as 20km, that may have formed by endogenic forces, such as tectonic and convective forces, or exogenic processes such as debris infall. We use high-resolution topographic data to conduct a topographic analysis of the ridge, which suggests a predominantly triangular morphology, with some ridge face slopes reaching 40°, allowing for an exogenic formation mechanism.

Structure and contents of layered classification system of digital geomorphology for China

This paper presents the structure and contents of a standardized layered classification system of digital geomorphology for China. This digital classification method combines landforms characteristics of morphology with genesis. A total of 15 categories of exogenic and endogenic forces are divided into two broad categories: morpho-genetic and morpho-structural landforms. Polygon patches are used to manage the morpho-genetic types, and solitary points, lines and polygons are used to manage the morpho-structural types. The classification method of digital morpho-genetic types can be divided into seven layers, i.e. basic morphology and altitude, genesis, sub-genesis, morphology, micro-morphology, slope and aspect, material and lithology. The method proposes combinations of matrix forms based on layered indicators. The attributes of every landform types are obtained from all or some of the seven layers. For the 15 forces categories, some classification indicators and calculation methods are presented for the basic morphology, the morphologic and sub-morphologic landforms of the morpho-genetic types. The solitary polygon, linear and point types of morpho-structural landforms are presented respectively. The layered classification method can meet the demands of scale-span geomorphologic mapping for the national primary scales from 1:500,000 to 1:1,000,000. The layers serve as classification indicators, and therefore can be added and reduced according to mapping demands, providing flexible expandability.

Thermal history of the central Gotthard and Aar massifs, European Alps: Evidence for steady state, long‐term exhumation

Quantifying long‐term exhumation rates is a prerequisite for understanding the geodynamic evolution of orogens and their exogenic and endogenic driving forces. Here we reconstruct the exhumation history of the central Aar and Gotthard external crystalline massifs in the European Alps using apatite and zircon fission track and apatite (U‐Th)/He data. Age‐elevation relationships and time‐temperature paths derived from thermal history modeling are interpreted to reflect nearly constant exhumation of ∼0.5 km/Ma since ∼14 Ma. A slightly accelerated rate (∼0.7 km/Ma) occurred from 16 to 14 Ma and again from 10 to 7 Ma. Faster exhumation between 16 and 14 Ma is most likely linked to indentation of the Adriatic wedge and related thrusting along the Alpine sole thrust, which, in turn, caused uplift and exhumation in the external crystalline massifs. The data suggest nearly steady, moderate exhumation rates since ∼14 Ma, regardless of major exogenic and endogenic forces such as a change to wetter climate conditions around 5 Ma or orogen‐perpendicular extension initiated in Pliocene times. Recent uplift and denudation rates, interpreted to be the result of climate fluctuations and associated increase in erosional efficiency, are nearly twice this ∼0.5 km/Ma paleoexhumation rate.

Twenty-five years of ultrahigh-pressure metamorphism Preface

This special issue of the European Journal of Mineralogy is dedicated to ultrahigh-pressure (UH P ) metamorphism and its increasing role in the geosciences. The term UH P metamorphism refers to those rock types that were formed or embedded in shallow levels of the continental or oceanic lithosphere and subsequently experienced PT -conditions within or above the lower limits of the coesite stability field. It was 25 years ago that Christian Chopin discovered metamorphic coesite in “pyrope-quartzites” from the Dora-Maira Massif, Italian Western Alps (Chopin, 1984). In the same year, Dave Smith found coesite in eclogites from the Western Gneiss Region, Norway (Smith, 1984). At that time, UH P metamorphism was thought to represent a rather “exotic” type of metamorphic grade. However, the worldwide importance of these rocks is now documented in more than 25 recognized UH P terranes. Thus, UH P metamorphism is far from an “exotic” process, and reflects its significance regarding global endogenic forces. Only through the application of fundamental mineralogical and petrological methodologies was it possible to decode burial and subsequent exhumation of UH P metamorphic rocks. It is clear that all other disciplines of solid earth sciences are affected as a …

Biological energy in landscape evolution

Traditional conceptual models of landscape evolution view topography as an outcome of endogenic forces (uplift) working against exogenic forces of denudation. The energy considerations of these concepts have focused on the conversion of the potential energy of landscape relief to kinetic energy. The concept of the biosphere as a planetary membrane for capturing and converting solar energy, coupled with the critical geomorphic role of biota, call for a consideration of biotic contributions to geomorphic work. A review of estimates of global rates of kinetic energy of denudation and uplift, and net primary production (NPP) indicates that the energy density of NPP is, on average, three to seven orders of magnitude greater than the others. If even a tiny fraction of NPP is geologically significant, then the biological subsidy to the energy of landscape evolution must be considered on a par with that of geophysical and geochemical phenomena. A case study in eastern Kentucky shows that even if only 0.1 percent of NPP is geomorphically significant, it still far exceeds the energy inputs from uplift and conversion of potential to kinetic energy by denudation. This is unlikely to be unique, though the relative importance of biological and geophysical processes must obviously vary with climate, tectonic setting, and other factors. Results indicate that, particularly where biological activity is significant, geomorphic work performed by biota may be greater than that associated with endogenic processes and with the kinetic energy of denudation.

Classification and characteristics of karst reservoirs in China and related theories

Abstract Karst reservoirs are distributed widely in China, for which integrated geological, logging, testing, and seismic identification marks can be made and their ages can be determined using unconformity surfaces, the lithologic features, and paleobiology of cavern clastic fillings and element geochemistry. The karst reservoirs can be classified as buried hill karst, reef-bank karst, internal karst, bedding deep-underflow karst, vertical deep-infiltration karst, and hydrothermal fluid karst. The first three belong to base-level karsts, controlled by different-order sequence interfaces; the last three belong to nonbase-level karsts, which are controlled by tectonics and fracture. The division of karst facies should take full account of the internal relation of the base-level karsts and the nonbase-level karsts, the existence of deep-turbulent flow zones and the genetic type of karsts. There are many types of corrosion fluid in carbonate rocks in petroleum basins. It is important for the reservoir evaluation and prediction to reconstruct them and to analyze the genetic mechanics of the karst pore-cave-fracture and large-scale cave. As for the controlling factors for the karst development, the study of zonal exogenic forces should be enhanced while the study of azonal endogenic forces is emphasized.

Penecontemporaneous non-tectonic brecciation of unconsolidated silts and muds

At several localities sediments have been found which partly or completely consist of angular fragments. From the geological context it is clear that the fine-grained parent material was broken up after deposition. This cannot be explained by endogenic forces, so that sedimentary and diagenetic (penecontemporaneous) processes must be the cause. Occurrences from Poland and The Netherlands are described, together with an analysis of the brecciation processes. These breccias are the result of pressure which may have been cryostatic, or caused by bioturbation, flowage of liquified material or similar processes.

The hypsometric curve of Mars

For the construction of the hypsometric curve of Mars the topographic map of the planet produced by the U.S.G.S. has been utilized. All the areas delimited by isolines and geographic grid have been measured, then summing all the contributions given by the areas included between the same isolines. Such measurements have been effected by means of a solid-state optical image analyzer. A comparative study of the hypsometric curves of the Earth and the Moon shows that, on Mars, several processes of vertical differentiation of the crust started, but did not develop completely owing to the exhaustion of the endogenic forces which determine the surficial dynamics of a planet. A model of the evolution of the Martian crust is discussed in order to justify the shape of the hypsometric curve.

The principle of antagonism in the earth's evolution

It is shown that for a complete geological interpretation of the evolution of the Earth, the principle of antagonism between endogenic and exogenic forces must be consistently applied. Inasmuch as the nature of the endogenic forces is random, it is possible to distinguish between effects of the two types of forces by a statistical test for nonrandomness (or randomness). Examples are given. Thus it is, e.g., shown that the orientation of valley trends in Switzerland is non-random; therefore the pre-design of the Swiss valleys is of tectonic, not erosive origin.

Evidence for lunar volcano-tectonic features

Objections to large-scale lunar volcanism are partly based on the small maximum diameter of terrestrial volcanic craters compared with lunar craters and on the association of terrestrial volcanoes with oceanic ridges and geosynclinal-orogenic belts, which seem to be absent on the moon. Actually, terrestrial volcano-tectonic complexes comparable in size (diameter up to 180 km) and morphology, to large lunar craters are also distributed independently of oceanic ridges and geosynclinal-orogenic belts; their relationships to tectonic plates are poorly understood. They are characteristic of areas of fracture tectonics, including platforms, and outnumber known impact craters between 5 and 10:1. Volcanic rocks that erupted from volcano-tectonic complexes have episodically ‘overplated’ continents, contributing significantly to their crust. On the moon the volcanic episodes appear to have been fewer, and endogenic forces were insufficient to initiate geosynclines, welts resembling oceanic ridges, and tectonic plates. Instead, ‘overplating’ may have played a major role in forming the lunar surface during devolatilization early in lunar history. If so, it resulted in formation of volcano-tectonic ‘craters’ controlled by the lunar tectonic grid, a system of fractures similar to those of the earth's platforms. Terrestrial volcano-tectonic complexes that characterize overplated areas tend to be rimmed by volcanic and subvolcanic domes, arcuate-to-circular or polygonal in plan (confocal subvolcanic or 'ring-dike complexes). A sample of over 400 reveals at least four major types: (1) calc-alkalic to peralkalic parent magma, (2) high-alkali feldspathoidal complexes, (3) basaltic complexes, and (4) layered complexes of ultramafic rocks and anorthosite.

SOURCES OF ENERGY IN GEOCHEMICAL PROCESSES

Large sources of energy are required to account for all known past and continuing geological processes. Exogenic forces are fed by solar energy but the source of endogenic forces are not so clearly understood. Earlier theories to account for such energy such as residual heat from an originally molten earth and accumulation of heat from radioactive minerals are in conflict with known facts. There exists a basic difference between the lattice structure of magmatic and highgrade metamorphic rocks on the one hand and sedimentary and low-grade metamorphic rocks on the other; in the former the basic lattice structure is one A1 atom and four O atoms in tetrahedral form, in the latter it is one A1 atom and six O atoms in octahedral form. Similar distinctions are noted for other elemental associations, The bonding properties of A1 and Si in the former class of rocks are covalent, in the latter one finds the bonds between A1 and O to be ionic and between S and O, half ionic. This indicates that the two groups repre...