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    ABSTRACT: Fault linkage plays an important role in the growth of faults. In this paper we analyze a published synthetic model to simulate fault linkage. The results of the simulation indicate that fault linkage is the cause of the shallower local slopes on the length–frequency plots. The shallower local slopes lead to two effects. First, the curves of log cumulative number against log length exhibit fluctuating shapes as reported in literature. Second, for a given fault population, the power-law exponents after linkage are negatively related to the linked length scales. Also, we present datasets of fault length measured from four structural maps at the Cantarell oilfield in the southern Gulf of Mexico (offshore Campeche). The results demonstrate that the fault length data, corrected by seismic resolution at the tip fault zone, also exhibit fluctuating curves of log cumulative frequency vs. log length. The steps (shallower slopes) on the curves imply the scale positions of fault linkage. We conclude that fault linkage is the main reason for the fluctuating shapes of log cumulative frequency vs. log length. On the other hand, our data show that the two-tip faults are better for linear analysis between maximum displacement (D) and length (L). Evidently, two-tip faults underwent fewer fault linkages and interactions.
    Journal of Geodynamics 01/2010; 49(1):24-30. DOI:10.1016/j.jog.2009.08.002 · 2.62 Impact Factor
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    ABSTRACT: For exploration and development the geologists and engineers try to know the true stratigraphic thickness (t). The monoclinal and folded bed models are published methods for t calculation. Both models assume parallel beds which can lead to significant deviations. In order to calculate the values of t considering the effects of both folding and stratigraphic variation we propose the 'folded wedge model'. Three are considered: β<sub align="right"> 1 </sub>, the bed dip at the point where the well enters; β<sub align="right"> 2 </sub>, the bed dip at the point where the well leaves; and α, the deviated angle of borehole (angle between vertical and borehole). Three values of t can be obtained: the value measured normal to top (t<sub align="right"> 6 </sub>); the value measured normal to bottom (t<sub align="right"> 7 </sub>); the average value measured normal to bottom and top (t<sub align="right"> 8 </sub>). The folded wedge model is applied to the Cantarell oil field complex obtaining more reasonable values of t than using the existing methods. [Received: August 16, 2009; Accepted: February 10, 2010]
    International Journal of Oil Gas and Coal Technology 01/2010; 3(3):245 - 268. DOI:10.1504/IJOGCT.2010.035374 · 0.43 Impact Factor
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    ABSTRACT: The Global Stratotype Section and Point (GSSP) for the Cretaceous/Paleogene (K/Pg) boundary was defined at the base of the boundary clay at a section near El Kef Tunisia, but the outcrop became quite deteriorated. In order to better characterize the boundary and to solve problems of correlation, several auxiliary sections are designed and described in detail including: Al'n Settara and Ellès in Tunisia, Caravaca and Zumaya in Spain, Bidart in France and El Mulato and Bochil in Mexico. These sections are the most continuous, expanded and representative of marine sedimentation in areas proximal and distal to the Chicxulub meteorite impact site. In addition, these sections are classical, very well known, physically accessible, have been exhaustively studied and allow a very detailed global correlation. The correlation criteria used were the meteorite impact evidence (Ir anomaly, Ni-rich spinel, etc.) and the mass extinction of planktic micro- and nannofossils. Furthermore, it was proposed that the K/Pg boundary is marked exactly by the moment of the meteorite impact, which implies that all the sediments generated by the impact belong to the Paleogene. While in distal areas to the impact site the K/Pg boundary coincides with a millimetre-thick rusty layer, in proximal areas the K/Pg boundary correlates to the base of a metre-thick Clastic Unit, including a thick calcareous breccia in the sections closer to the impact crater.
    Episodes 06/2009; 32(2):84-95. · 1.38 Impact Factor
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    ABSTRACT: Fault slip and fault separation are generally not equal to each other, however, they are geometrically related. The fault slip (S) is a vector with a magnitude, a direction, and a sense of the movement. In this paper, a series of approaches are introduced to estimate quantitatively the magnitude and direction of the fault slip using fault separations. For calculation, the known factors are the pitch of slip lineations (γ), the pitch of a cutoff (β), the dip separation (Smd) or the strike separation (Smh) for one marker. The two main purposes of this work include: (1) to analyze the relationship between fault slip and fault separation when slickenside lineations of a fault are known; (2) to estimate the slip direction when the parameters Smd or Smh, and β for two non-parallel markers at a place (e.g., a point) are known. We tested the approaches using an example from a mainly strike-slip fault in East Quantoxhead, United Kingdom, and another example from the Jordan Field, Ector County, Texas. Also, we estimated the relative errors of apparent heave of the normal faults from the Sierra de San Miguelito, central Mexico.
    Journal of Structural Geology 10/2007; 29(10):1709-1720. DOI:10.1016/j.jsg.2007.06.003 · 2.42 Impact Factor
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    Journal of Canadian Petroleum Technology 01/2007; 46(11). DOI:10.2118/07-11-CS · 0.62 Impact Factor
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    ABSTRACT: Problems with measuring fault slip in the subsurface can sometimes be overcome by using subsurface structural contour maps constructed from well logs and seismic information. These maps are useful for estimating fault slip since fault motion commonly causes the dislocation of structural contours. The dislocation of a contour is defined here as the distance in the direction of fault strike between two contours which have the same value on both sides of a fault. This dislocation can be estimated for tilted beds and folded beds as follows:(i) If a dip-slip fault offsets a tilted bed, the dislocation (Sc) of contours can be estimated from the vertical component (Sv) of the fault slip and the dip (β) of the bedding according to the following relationship: Sc= Sv/tan β. Since Sc and β can be measured from a contour map, the vertical component of fault slip can be obtained from this equation.If a strike-slip fault offsets a tilted bed, the dislocation (Scs) of contours is equal to the strike-slip of the fault (Sc), that is, Scs= Ss.(ii) If a fault offsets a symmetric fold, the strike component (Scs) of fault slip and the dislocation of the contours (Sc) can be calculated, respectively, from the equations Scs= (Smax+ Smin) / 2 and Sc= (Smax - Smin) / 2. Smax is the greater total dislocation (Sc+ Scs) of a contour line between the two limbs of the fold and Smin is the smaller total dislocation (Sc - Scs) for the same contour line. In this case, Sv can be also calculated using the obtained value of Sc and the equation Sv= Sc tan β.Similarly, for an asymmetric fold, the dislocation of contours due to the vertical slip component is Scb= (Smax - Smin)/(n + 1), and the strike-slip component is Ss= Scs= (nSmin+ Smax/(n + 1), where n is the ratio between the values of interlines of the two limbs, and Scb is the dislocation of contours due to the vertical slip component for either of the two limbs (here it is for limb b).In all cases, three conditions are required for the calculation of contour dislocation:(i) the contour lines must be approximately perpendicular to the fault strike; the intersection angle between the fault strike and the strike of bedding should be greater than 65°;(ii) the bed must not be dip more than 35°; and(iii) folding or flexure of the stratigraphic horizons must have occurred before faulting.These methods for determining fault slip from the dislocation of structural contours are discussed using case studies from the Cantarell oilfield complex, Campeche Sound (southern Gulf of Mexico), the Jordan-Penwell Ellenburger oilfield in Texas, and the Wilmington oilfield in California.
    Journal of Petroleum Geology 06/2004; 27(3):277 - 298. DOI:10.1111/j.1747-5457.2004.tb00059.x · 1.53 Impact Factor
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    ABSTRACT: The main oil reservoir in the Cantarell Field, offshore Campeche, consists of a dolomitized carbonate breccia with an ejectsseal on top, considered to have been formed during the Chicxulub impact event. Two different dolomitization events have been identified associated with the reservoir. The first generation (D1) is a bright-red luminescent saddle dolomite while the second generation is a minute, non-luminescent dolomite (D2). Brine fluid inclusions show an evolution from D1 to D2 to higher temperatures (from 80–120 to 100–120 °C) and salinities (from 2–8 to 6–8 wt.% eq. NaCl). Hydrocarbon-bearing fluid inclusions evolved from heavy oils to light oils in D1 (from core to rim), while in D2, all inclusions appear to be formed by heavy oil with an 'API similar to the oil contained in the present reservoir. These facts suggest that the end of the dolomitization process was closely related with the beginning of the main accumulation of oil into the reservoir, displacing the aqueous fluids and precluding the precipitation of carbonates.
    Journal of Geochemical Exploration 05/2003; DOI:10.1016/S0375-6742(03)00085-2 · 2.43 Impact Factor
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    Martinez-Ibarra R · Tritlla J · Cedillo-Pardo E · Grajales-Nishimura J.M
    PACROFI; 01/2002
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    J. Smit · B. Roep · J. M. Grajales-Nishimura · J. Bermudez
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    ABSTRACT: The K/T boundary in marine deposits in and around the Gulf of Mexico at a dis- tance of
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    01/1994; 825:49.
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    ABSTRACT: (40)Ar/(39)Ar dating of drill core samples of a glassy melt rock recovered from beneath a massive impact breccia contained within the 180-kilometer subsurface Chicxulub crater in Yucatán, Mexico, has yielded well-behaved incremental heating spectra with a mean plateau age of 64.98 +/- 0.05 million years ago (Ma). The glassy melt rock of andesitic composition was obtained from core 9 (1390 to 1393 meters) in the Chicxulub 1 well. The age of the melt rock is virtually indistinguishable from (40)Ar/(39)Ar ages obtained on tektite glass from Beloc, Haiti, and Arroyo el Mimbral, northeastern Mexico, of 65.01 +/- 0.08 Ma (mean plateau age for Beloc) and 65.07 +/- 0.10 Ma (mean total fusion age for both sites). The (40)Ar/(39)Ar ages, in conjunction with geochemical and petrological similarities, strengthen the recent suggestion that the Chicxulub structure is the source for the Haitian and Mexican tektites and is a viable candidate for the Cretaceous-Tertiary boundary impact site.
    Science 09/1992; 257(5072):954-8. DOI:10.1126/science.257.5072.954 · 31.48 Impact Factor

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