13.4: Basins Caused by Strike-Slip Faulting
- Page ID
- 38112
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Tectonics and crustal dynamics
Strike-slip basins form in areas where the horizontal along fault-bounded crustal blocks causes localized zones of extension (transtension) or compression (transpression). We will focus mainly on extensional situations in the following text.
Extension commonly takes place where strike slip faults curve or bend (releasing bends). This localized extension is associated with near vertical faults or fault zones which bound blocks of downdropped crust. Given their close association with strike slip fault systems, tectonism (and thus sedimentation) in these basins is commonly episodic and corresponds to periods of activity along basin-bounding faults.
Figure \(\PageIndex{1}\): Series of maps showing the development of a pull-apart basin caused by a right lateral strike slip fault (Page Quinton via Wikimedia Commons; CC BY-SA 4.0 which is after Mann et al, 1983).
Morphology
Strike-slip basins are relatively small (tens to hundreds of km2) features that, in map view, are relatively narrow rhombohedral or lens-shaped features. The basin-bounding faults and/or fault zones are near vertical. In the case of pull-apart basins developed in association with releasing bends, the faults and long axis of the basin broadly parallels the bend and is oblique to the trend of the major strike-slip faults. Given the profound influence of local fault geometry, individual strike-slip basins and be internally segmented and linear arrays of individual basins can form in association with regional strike-slip fault zones. Although strike slip-basins are relatively small in terms of surface area, the basin fill can be hundreds to thousands of meters thick and relief along basin margins can be pronounced.
Figure \(\PageIndex{2}\): Cross sectional sketch of a pull-apart basin formed by a right lateral strike slip fault. (Page Quinton via Wikimedia Commons; CC BY-SA 4.0 which is based on Larue and Allen, 2021).Sedimentology
Given their small size, proximity to active faults, significant relief, and short transport distance, strike-slip basins is dominated by coarse-grained, immature clastic sediments including breccias, conglomerates, and sandstones deposited in association with alluvial fans and fluvial systems – particular during periods of active tectonism. During periods of quiescence and/or under certain climatic regimes, fine-grained mudrocks and sandstones associated with floodplains, lakes, and shallow marine deposits may be present. Abrupt facies changes are characteristic and soft-sediment deformation can be common.
Volcanism is rare given that these basins are typically not associated with sufficient crustal thinning to enable partial melting.