نتایج جستجو برای: sedimentary rock

تعداد نتایج: 48134  

2016
R. V. Morris D. T. Vaniman D. F. Blake R. Gellert S. J. Chipera E. B. Rampe D. W. Ming S. M. Morrison R. T. Downs A. H. Treiman A. S. Yen C. N. Achilles T. F. Bristow J. A. Crisp D. J. Des Marais J. D. Farmer K. V. Fendrich J. Frydenvang T. G. Graff J. P. Grotzinger J. M. Morookian S. P. Schwenzer

Morris, R. V.; Vaniman, D. T.; Blake, D. F.; Gellert, R.; Chipera, S. J.; Ming, D. W.; Morrison, S. M.; Downs, R. T.; Rampe, E. B.; Treiman, A. H.; Yen, A. S.; Achilles, C. N.; Bristow, T. F.; Fendrich, K.; Crisp, J. A.; Des Marais, D. J. ; Farmer, J. D. ; Grotzinger, J. P.; Morookian, J. M. and Schwenzer, S. P. (2016). High-Temperature, Perhaps Silicic, Volcanism on Mars Evidenced by Tridymite...

2017
V. E. D. OBOT

We performed a ground level geomagnetic survey of Greene County, Ohio in the fall of 1976. The geomagnetic map showed a positive magnetic anomaly running from the northwestern section to the southeastern section of the county while the remainder of the map was relatively undisturbed. We analyzed the localized anomaly of the southeastern section by the Peters methods and by fitting to the model ...

Journal: :Nature Geoscience 2021

Sedimentary rocks can release carbon dioxide (CO2) during the weathering of rock organic and sulfide minerals. This sedimentary could act as a feedback on Earth’s climate over millennial to geological timescales, yet environmental controls CO2 from are poorly constrained. Here, we directly measure flux 2.5 years at Draix-Bléone Critical Zone Observatory, France. Total fluxes approached values r...

2014
J. P. Grotzinger A. G. Hayes M. P. Lamb S. M. McLennan

The atmospheres of solid planets exert a fundamental control on their surfaces. Interactions between atmospheric and geologic processes influence the morphology and composition of surfaces, and over the course of geologic time determine the historical evolution of the planet’s surface environments including climate. In the case of Earth, the origin of life likely occurred within surface environ...

Journal: :journal of sciences islamic republic of iran 0
n. naimi ghassabiyan

the study area is situated in the middle part of the tabas block. it contains outcrops of rocks that formed along longitudinal faults in early cimmerian orogenic phase. the basin subsided along these faults from the late triassic to early cretaceous, which include two sedimentary cycles. a sedimentary cycle, related to upper triassic to bajocian is known as shemshak group. another sedimentary c...

1972
D. A. Summers

An investigation is made into the effects of water jet pressure, nozzle diameter, traverse speed of the nozzle over the rock surface and the number of times the jet passes over the same area on the penetration of a water jet into Indiana limestone. The effectiveness of the cut is judged on the depth of cut established and the specific energy of rock removal. Pressure is varied in the range from...

2014
Yong-Xiang Li Shipeng Wang Shaoying Fu Wenjun Jiao

*Correspondence: Yong-Xiang Li, State Key Laboratory for Mineral Research Deposits, School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210046, China e-mail: [email protected] Post-depositional compaction is an integral part of sedimentary rock formation and thus has been reasonably deemed as a major culprit for the long-recognized inclination-shallowing prob...

1999
Philip A. Meyers Elisabeth Lallier-Vergès

Identification of the sources of organic matter in sedimentary records provides important paleolimnologic information. As the types and abundances of plant life in and around lakes change, the composition and amount of organic matter delivered to lake sediments changes. Despite the extensive early diagenetic losses of organic matter in general and of some of its important biomarker compounds in...

2010
LAWRENCE POWELL

The carbonatite problem can be stated as follows: Are carbonatites genetically related to sedimentary carbonate rocks, or are they derived from a silicate parent material? The isotopic composition of strontium in 21 carbonatites and in several related alkaline rocks has been determined. The mean Sr87/$r86 ratio for the 21 carbonatites is 0.7065 + 0.0003. The Sr87/sr86 ratios of sedimentary carb...

1999
Ilya Muchnik Vadim Mottl

On the basis of the optimization-based approach to the analysis of massive ordered data sets, a new method is proposed for computer-aided interpretation of seismic exploratory data from the so-called crystalline basement of the Earth mantle, which underlies the relatively thin sedimentary cover having been, up to now, the almost exceptional object of seismic explorations. The seismic explorator...

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