Duricrusts

Dixon, John C.

doi:10.1007/978-94-015-8254-4_5

Cited by 12 publications

(10 citation statements)

References 76 publications

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“…The presence of rough‐textured, apparently indurated material exposed in the upper walls of many incised valleys (e.g., Figures 5, 8, 13, and 14) raises the possibility that a resistant layer, presumably a duricrust, has hardened the surface layers of much of the cratered highlands. In terrestrial arid and semi‐arid environments duricrusts sometimes develop sufficient strength and thickness to cause inverted topography during subsequent erosion [ Dixon , 1994]. Weak duricrusts have been found at the Viking, Pathfinder, and MER lander sites, but they would not be of sufficient strength to affect erosion.…”

Section: Discussion: Implications For Martian Erosional History and Ementioning

confidence: 99%

An intense terminal epoch of widespread fluvial activity on early Mars: 1. Valley network incision and associated deposits

2005

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[1] We present evidence that a final epoch of widespread fluvial erosion and deposition in the cratered highlands during the latest Noachian or early to mid-Hesperian was characterized by integration of flow within drainage networks as long as 4000 km and trunk valley incision of 50 to 350 m into earlier Noachian depositional basins. Locally deltaic sediments were deposited where incised valley systems debouched into basins. Large alluvial fans of sediment deposited from erosion of alcoves in steep crater walls probably formed contemporaneously. The depth of incision below Noachian surfaces correlates strongly with the gradient and the total valley length, suggesting consistent regional hydrology. Estimated discharges from channel dimensions indicate flow rates equivalent to mean annual floods in terrestrial drainage basins of equivalent size. Such high flow rates imply either runoff directly from precipitation or rapid melting of accumulated snow. Development of duricrusts on the Noachian landscape may have contributed to focusing of late-stage erosion within major trunk drainages. This latestage epoch of intense fluvial activity appears to be fundamentally different than the fluvial environment prevailing during most of the Noachian Period, which was characterized by widespread fluvial erosion of highlands and crater rims, deeply infilling crater floors, and intercrater basins through ephemeral fluvial activity, and development of local rather than regionally integrated drainage networks.

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Section: Discussion: Implications For Martian Erosional History and Ementioning

confidence: 99%

An intense terminal epoch of widespread fluvial activity on early Mars: 1. Valley network incision and associated deposits

2005

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“…The silicification proceeded in a vadose zone unfavourable for deep groundwater circulation (Głazek 1989;Głazek et al 1992;cf. Thiry and Milnes 1991;Dixon and McLaren 2009;Bustillo et al 2013) as an effect of descending solutions enriched in dissolved silica. This silica presumably originated from long-lasting (Thiry 1999) leaching of opal (cf.…”

Section: Discussionmentioning

confidence: 99%

Epigenetic silicification of the Upper Oxfordian limestones in the Sokole Hills (Kraków-Częstochowa Upland): relationship to facies development and tectonics

Matyszkiewicz¹,

Kochman²,

Rzepa³

et al. 2015

Acta Geologica Polonica

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ABSTRACT:Matyszkiewicz, J., Kochman, A., Rzepa, G., Gołębiowska, B., Krajewski, M., Gajdzik, K. and Żaba, J. 2015. Epigenetic silicification of the Upper Oxfordian limestones in the Sokole Hills (Kraków-Częstochowa Upland): relationship to facies development and tectonics. Acta Geologica Polonica, 65 (2), 181-203. Warszawa.A spectacular epigenetic silicification was encountered in the Oxfordian bedded limestones exposed in the Sokole Hills situated in the Kraków-Częstochowa Upland. The main epigenetic mineral is microcrystalline quartz accompanied by minor goethite, hematite, barite, galena and sphalerite. Locally, the mineralized limestones reveal Pb and Cu contents exceeding over 150 times the background values of these metals in unmineralized limestones.The epigenetic mineralization of the bedded limestones was probably a two-stage process. During the first, Early Cretaceous stage, silicified limestones formed at the erosional surface of a denuded carbonate complex. Such silicification greatly limited the progress of the first karstification phase of the Upper Jurassic carbonates initiated in the Hauterivian. The sources of silica accumulated in the limestones were descending solutions enriched in silica derived from the weathering zone. This silicification affected the topmost part of the Upper Jurassic massive limestones and the deeper portions of the bedded limestones along the fracture systems and stylolites.Early Cretaceous tectonic activity generated new dislocations and re-opened the existing faults, which were subsequently filled with permeable Albian quartz sands. These openings became the migration pathways for ascending, warm, relict, sulphide-carrying hydrothermal solutions at the second formation stage of the epigenetic mineralization. The newly supplied silica from the Albian sands precipitated on the silicified limestones and, as concentric rims, on brecciated, early diagenetic cherts. The second-stage mineralization proceeded under phreatic conditions, presumably close to a fluctuating mixing zone of ascending, warm hydrothermal solutions and descending cold groundwaters. The brecciated cherts acting as silica crystallization nuclei indicate that the last mineralization stage probably followed the final phase of Cenozoic faulting.

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“…These soils are characterized, in part, by the accumulation of soluble salts and the notable absence of an organic "O" horizon (Southard, 2000). The occurrence of carbonate in the vicinity of plant roots is widely documented (Klappa, 1980;Phillips et al, 1987;McLaren, 1995;Dixon and McLaren, 2009). However, plants play a crucial role in the concentration of carbonate within soil profiles.…”

Section: Soil Properties and Vegetationmentioning

confidence: 99%

“…This pattern is complicated, however, by the fact that parent-material properties strongly influence the patterns of carbonate and salt accumulations (see McLaren, 2009 andDixon, 2009 for detailed discussions). In more arid environments, depths are generally shallower, whereas in wetter environments depths are greater.…”

Section: Accumulation Of Calcium Carbonate and Soluble Saltsmentioning

confidence: 99%

Duricrusts

Cited by 12 publications

References 76 publications

An intense terminal epoch of widespread fluvial activity on early Mars: 1. Valley network incision and associated deposits

An intense terminal epoch of widespread fluvial activity on early Mars: 1. Valley network incision and associated deposits

Epigenetic silicification of the Upper Oxfordian limestones in the Sokole Hills (Kraków-Częstochowa Upland): relationship to facies development and tectonics

Soil Morphology in the Critical Zone: The Role of Climate, Geology, and Vegetation in Soil Formation in the Critical Zone

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