The post-Messinian translation of the Southern Apennines-Calabrian Arc in the Bradano basin (Northern Ionian Sea)

<p>In Northern Calabria, the Southern Apennines orogenic wedge bends and passes to the Calabrian Arc while they are both colliding with the subducting Apulia plate. The boundary between Southern Apennines and Calabrian Arc is commonly placed along the NW-SE trending Sangineto Lineament whose offshore prolongation is not clearly defined. A multi-scale seismic reflection dataset combined with exploration wells and seafloor bathymetry allowed us to define the post-Messinian tectono-sedimentary evolution of the Bradano Basin adjacent to the orogenic belt.  </p><p>After Messinian times, two main tectono-sedimentary events deeply modified the Bradano Basin. During the first event (early Pliocene-early Pleistocene), a left-lateral transpressive system, about 20-30 km wide, was part of an oblique convergent margin along which the Southern Apennines and the Calabrian Arc collided; remnants of this transpressive system are now buried under the western portion of the Bradano Basin near the Calabrian margin. Shelf to deep marine turbiditic deposits were prevailing during this first event. Around the Pliocene-Pleistocene boundary (2.58 Ma), a sudden and widespread basin rearrangement occurred. During the second event (early Pleistocene-Present) the orogenic front of the Southern Apennines and the earlier transcurrent systems were suddenly translated to the NE of about 50 km and the left-lateral transpressive boundary between the Southern Apennines and Calabrian Arc became part of the orogenic wedge. During this second event, both upper and lower converging plates were shortened together along multiple detachments levels and out-of-sequence thrusts. The second tectono-sedimentary event is characterized by prograding deltaic and shelfal deposits that seal the earlier transpressive system and pass to deep marine deposits in the central part of the Bradano basin.</p><p>The study reveals that the eastern boundary between Southern Apennine and Calabrian Arc is a wide deformation belt including the Sangineto Lineament while the Messinian-Pliocene orogenic transpressive system is buried and translating toward the NE since Early Pleistocene.</p>

Landscape Records 25 Million Years of Tectonic Evolution at an Oblique Convergent Margin, Marlborough Fault System, New Zealand

<p>The landscape at the NE end of the South Island, New Zealand, records oblique plate collision over the last 25 million years. Using low-temperature thermochronology, geomorphic analyses, and cosmogenic <sup>10</sup>Be data, we document the landscape response to tectonics over long (10<sup>6</sup>) and short (10<sup>2</sup> – 10<sup>3</sup>) timescales in the Marlborough Fault System (MFS) and related Kaikōura Mountains. Our results indicate two broad stages of landscape evolution that reflect a changing plate boundary through time. In the eastern MFS, Miocene folding above blind thrust faults generated prominent Kaikōura Mountain peaks and formed major transverse rivers early in the plate collision history. By the Pliocene, rotation of the plate boundary led to a transition to dextral strike-slip faulting and widespread uplift that led to cycles of river channel offset, deflection and capture of tributaries draining across active faults, and headward erosion and captures by major transverse rivers within the western MFS. Despite clear evidence of recent rearrangement of the western MFS drainage network, rivers in this region still flow parallel to older faults, rather than along orthogonal traces of younger, active strike-slip faults. Such drainage patterns emphasize the importance of river entrenchment, showing that once rivers establish themselves along a structural grain, their capture or avulsion becomes difficult, even when exposed to new weakening and tectonic strain. Over short timescales (hundreds to thousands of years), apparent catchment-wide average erosion rates derived from <sup>10</sup>Be data show an increase from SW to NE, along strike of the Seaward Kaikōura Range. These rates mirror spatial increases in elevation, slope, channel steepness, and coseismic landslides, demonstrating that both landscape and geochronology patterns are consistent with an increase in rock uplift rate toward a subduction front that is presently locked on its southern end. Remarkably, the form of the topography, hillslopes, and rivers across much of the MFS appears to faithfully record the complex and changing tectonic history of a long-lived, oblique convergent plate boundary.</p>

Activity of crustal faults and the Xolapa sliver motion in Guerrero–Oaxaca forearc of Mexico, from seismic data

Oblique convergent margins often host forearc slivers separated by the subduction interface and a trench parallel strike-slip fault system in the overriding plate. Mexican oblique subduction setting led to the formation of a forearc sliver and accomodation of part of the slip at the bounding system of strike-slip faults. The Xolapa sliver is, on average, a $$\sim 105$$ ∼ 105 -km-wide crustal block located along the coast of Guerrero and Oaxaca states of Mexico, and is limited by a $$\sim 650$$ ∼ 650 -km-long La Venta-Chacalapa fault zone. Two types of datasets, local catalog and Global CMT compilation, are used to estimate the motion of the Xolapa sliver using the rigid block model that describes the phenomenon of slip partitioning. According to the results obtained from local and Global CMT catalogs for selected subduction thrust earthquakes, the forearc sliver moves southeastwards with respect to the fixed North America plate at the rate of 10 ± 1 mm/year and 5.6 ± 0.8 mm/year, respectively. These velocities in general agree with the values obtained from long-term GPS observations (5–6 mm/year). The origin of the inconsistency between local and teleseismic estimates is attributed to a difference in the double couple focal mechanism parameters for two types of datasets. Convergence obliquity changes from $$10.42{^\circ }$$ 10.42 ∘ and the rate of 58 mm/year to $$13.29{^\circ }$$ 13.29 ∘ at the rate of 68 mm/year along the Guerrero and Oaxaca coast increasing from northwest to southeast; therefore, the Xolapa sliver is supposed to be stretched. However, the slip vector azimuths of thrust subduction earthquakes tend to approach plate convergence vectors southeastwards along the coast; so, we assume that this may produce the forearc block compression.

Structural complexity in the boundary of forearc basin – accretionary wedge in the northwesternmost Sunda active margin

The area from Andaman to northern Sumatran margin is a region where major faults collided that complicates the structural configuration. The origin of structures in the boundary between the accretionary wedge and forearc basin in the northwesternmost segment of the Sunda margin has been a subject of debates. This article reviews several published works on the Andaman – north Sumatran margin to characterize the boundary between forearc basin and accretionary wedge. Complex strain partitioning in this margin is characterized by sliver faults that crossing boundaries between the backarc basin, volcanic arc, forearc basin, and accretionary wedge. The fault zone can be divided into two segments: The West Andaman Fault (WAF) in the north and Simeulue Fault (SiF) in the southern part. A restraining step-over formed in between WAF and SiF. The SiF may extent onshore Simeulue to a strike-slip fault onshore. Strain-partitioning in such an oblique convergent margin appears to have formed a new deformation zone rather than reactivated the major rheological boundary in between the accretionary wedge and forearc basin. The eastern margin of the Andaman-north Sumatra accretionary wedge appears to have form as landward-vergent backthrusts of Diligent Fault (DF) and Nicobar Aceh Fault (NAF) rather than strike-slip faults. This characteristic appears to have formed in the similar way with the compressional structures dominated the eastern margin accretionary wedge of the central and south Sumatra forearc. Keywords: Andaman, North Sumatra, forearc, structure, accretionary wedge, strain partitioningDaerah Andaman - Sumatera bagian utara adalah wilayah di mana patahan-patahan besar saling bertemu dan membuat konfigurasi struktur menjadi rumit. Asal-usul struktur di batas antara prisma akresi dan cekungan busur muka di bagian paling baratlaut dari tepian Sunda telah menjadi topik perdebatan. Artikel ini mengulas beberapa studi yang telah diterbitkan sebelumnya mengenai tepian Andaman - Sumatra bagian utara untuk mengkarakterisasikan batas antara cekungan muka dan prisma akresi. Pemisahan regangan yang kompleks di tepian ini dicirikan oleh sliver fault yang melintasi batas antara cekungan busur belakang, busur vulkanik, cekungan busur muka, dan prisma akresi. Zona sesar tersebut dapat dibagi menjadi dua segmen, yaitu Sesar Andaman Barat (WAF) di utara dan Simeulue Fault (SiF) di bagian selatan. Sebuah restraining step-over terbentuk di antara WAF dan SiF. SiF kemungkinan menerus sampai ke Pulau Simeulue dan menyatu dengan sesar geser. Pemisahan regangan di tepian konvergen yang miring seperti itu tampaknya telah membentuk zona deformasi baru daripada mengaktifkan kembali batas reologi utama di antara prisma akresi dan cekungan busur muka. Batas bagian timur dari prisma akresi di Andaman – Sumatera bagian utara memiliki bentuk sebagai backthrusts berarah darat yaitu Sesar Diligent (DF) dan Sesar Nicobar Aceh (NAF) dan bukan merupakan sesar geser. Karakteristik ini tampaknya terbentuk dengan proses yang mirip dengan struktur-struktur kompresional yang mendominasi bagian timur prisma akresi di daerah Sumatra bagian tengah dan selatan.Kata kunci: Andaman, Sumatera bagian, busur muka, struktur, prisma akresi, pemisahan regangan

RECORDING AND MODELING OF FORTRESSES AND CASTLES WITH UAS. SOME STUDY CASES IN JAEN (SOUTHERN SPAIN)

The province of Jaen (Southern Spain) has one of the largest concentrations of medieval fortresses of all Europe. Moreover ancient Iberian settlements located in <i>oppida</i> (fortified villages) and dated at VI-IV BC also are outstanding examples of historical heritage landmarks in the region. Most of these places are being restored or under documentation analysis to prevent their progressive deterioration. These places have several geometric characteristics in common, such as isolated locations, elongated shapes, largemedium size objects (in the order of tens to few hundred of meters), architectural features with vertical development (such as masonry or rammed earth walls, towers, gates, battlements, etc) or without it (walls, buildings or paths layouts at ground level). The object size, the required level of details and accuracy (of the order of some few cm) and both vertical and horizontal features imply that present UAS techniques can be advantageously used with respect to conventional aerial and terrestrial photogrammetric techniques. Vertical stereoscopic and oblique convergent UAS photogrammetric networks combined with processing techniques based on Structure from Motion (SfM) algorithms allow detailed low cost 2D/3D products. The proper selection of the UAS, camera, image acquisition mode (stop and/or cruising), the network and the processing software will determine the quality of final products and their usefulness in metric documentation, 3D modelization or museology. The efficiency of the use of UAS has been analyzed in several selected examples in Jaen (Burgalimar and Berrueco castles, Xth and XIIIth centuries, respectively, and the Iberian Puente Tablas oppidum, Vth-IVth centuries BC).

RECORDING AND MODELING OF FORTRESSES AND CASTLES WITH UAS. SOME STUDY CASES IN JAEN (SOUTHERN SPAIN)

The province of Jaen (Southern Spain) has one of the largest concentrations of medieval fortresses of all Europe. Moreover ancient Iberian settlements located in &lt;i&gt;oppida&lt;/i&gt; (fortified villages) and dated at VI-IV BC also are outstanding examples of historical heritage landmarks in the region. Most of these places are being restored or under documentation analysis to prevent their progressive deterioration. These places have several geometric characteristics in common, such as isolated locations, elongated shapes, largemedium size objects (in the order of tens to few hundred of meters), architectural features with vertical development (such as masonry or rammed earth walls, towers, gates, battlements, etc) or without it (walls, buildings or paths layouts at ground level). The object size, the required level of details and accuracy (of the order of some few cm) and both vertical and horizontal features imply that present UAS techniques can be advantageously used with respect to conventional aerial and terrestrial photogrammetric techniques. Vertical stereoscopic and oblique convergent UAS photogrammetric networks combined with processing techniques based on Structure from Motion (SfM) algorithms allow detailed low cost 2D/3D products. The proper selection of the UAS, camera, image acquisition mode (stop and/or cruising), the network and the processing software will determine the quality of final products and their usefulness in metric documentation, 3D modelization or museology. The efficiency of the use of UAS has been analyzed in several selected examples in Jaen (Burgalimar and Berrueco castles, Xth and XIIIth centuries, respectively, and the Iberian Puente Tablas oppidum, Vth-IVth centuries BC).