West Iberia Research Articles

Serpentinization and magmatism during extension at non-volcanic margins: the effect of initial lithospheric structure

Abstract At several non-volcanic margins serpentinized peridotites occur within a wide continent-ocean transition (COT) and beneath the edge of the thinned continental crust. However, other margins such as the Woodlark Basin appear to have a sharp COT and no reported serpentinites. We investigate the thermal, magmatic and rheological evolution of margins during extension as a function of initial lithospheric structure, rift duration and stretching factor. For cratonic and old orogen models, the entire crust should become brittle at stretching factors c. 3–4. The resultant crust-cutting faults allow water to reach and serpentinize the mantle, leading to the development of serpentinite décollements at the crust-mantle boundary and exhumation of mantle at the COT. Our predictions are consistent with the spatial limit and thickness of serpentinites at the SW Greenland and West Iberia margins, and the Rockall Trough. They also explain the absence of a broad zone of unroofed, serpentinized mantle at the COT of the Woodlark Basin: here the crust was too thick and hot for serpentinites to form before break-up. Larger melt production than in the West Iberia type margins and concentration of the lithospheric strength in the crust leads to synchronous crustal separation and lithospheric failure, yielding a sharp COT.

The role of detachment faulting in the formation of an ocean-continent transition: insights from the Iberia Abyssal Plain

Abstract The Iberia Abyssal Plain segment of the West Iberia margin was drilled during Ocean Drilling Program Legs 149 and 173 and has been extensively studied geophysically. We present new microstructural investigations and new age data. These, together with observed distribution of upper- and lower-crustal and mantle rocks along the ocean-continent transition suggest the existence of three detachment faults, one of which was previously unrecognized. This information, together with a simple kinematic inversion of the reinterpreted seismic section Lusigal 12, allows discussion of the kinematic evolution of detachment faulting in terms of the temporal sequence of faulting, offset along individual faults, and thinning of the crust during faulting. Our study shows that the detachment structures recognized in the seismic profile became active only during a final stage of rifting when the crust was already considerably thinned to c. 12 km. The total amount of extension accommodated by the detachment faults is of the order of 32.6 km corresponding to a β factor of about two. During rifting, the mode of deformation changed oceanwards. Initial listric faulting led to asymmetric basins, accommodating low amounts of extension, and was followed by a situation in which the footwall was pulled out from underneath a relatively stable hanging wall accommodating high amounts of extension. Deformation along the latter faults resulted in a conveyor-belt type sediment accumulation in which the exhumed footwall rocks were exposed, eroded and redeposited along the same active fault system.

Nature of the continent-ocean transition on the non-volcanic rifted margin of the central Great Australian Bight

Abstract A region of 50–120 km width defines the continent-ocean transition (COT) in the central Great Australian Bight. It is characterized by a thin apron of post-break-up sediments overlying complexly deformed sediments and intruded crust bounded landward by a basement ridge complex and oceanward by rough oceanic basement. Recently acquired deep reflection and refraction seismic data have significantly enhanced understanding of the COT and basement ridge. Modelled gravity and magnetic data, and features interpreted from seismic data, are consistent with aspects of extensional and break-up models proposed for the West Iberia margin. Many of the features and relationships observed beneath the outer margin of the central Great Australian Bight can be explained by extension within a lithosphere-scale ‘pure-shear’ environment involving four layers: brittle upper crust and upper mantle, and ductile lower crust and lower lithospheric mantle. The COT is interpreted to be underlain by extended continental lithosphere. Thus, the continent-ocean boundary is unequivocally defined between oceanic crust and the COT and appears to be associated with sea-floor spreading magnetic anomaly 33, indicating that break-up and sea-floor spreading did not commence until c. 83 Ma (early Campanian time), later than the currently accepted 95 Ma age. The major part of the basement ridge complex is probably a combination of serpentinized peridotites and mafic intrusions or extrusions derived by mantle upwelling and limited partial melting. The magmatic products of this process probably cooled during chron 34 producing a distinctive magnetic anomaly, but one that does not relate to break-up and sea-floor spreading.

Non-volcanic rifted margins, continental break-up and the onset of sea-floor spreading: some outstanding questions

Abstract During the last 20 years, regional studies on the West Iberia margin and on the former margins of the Tethys have considerably advanced the understanding of processes related to continental break-up and the onset of sea-floor spreading. However, some questions remain outstanding. To tentatively answer these, a coherent interpretation of available data is proposed, based on the detachment fault concept applied to the continental as well as the oceanic lithosphere, and on the hypothesis of a multi-staged rifting process. The interpretation addresses the nature of the lower crust beneath non-volcanic passive margins, the origin of ophicalcites, the probable time gap between syn- or post-rift crystallization of gabbros and extrusion of basalts on the sea floor, and the significance of dipping reflectors within oceanic lithosphere adjacent to non-volcanic passive margins. The interpretation also considers the symmetry v. asymmetry of continental rifting and break-up, the location of the ocean-continent boundary, and the possible association of magnetic quiet zones with ultramafic sea floor (serpentinized peridotite) bordering non-volcanic passive margins.

The evolution of amphibolites from Site 1067, ODP Leg 173 (Iberia Abyssal Plain): Jurassic rifting to the Pyrenean compression

Abstract During ODP Leg 173 (April–May 1997) five new sites (1065, 1067–1070) were drilled at the ocean-continent transition (OCT) zone off the West Iberia margin in the Iberia Abyssal Plain. At Site 1067 the 92 m of cored amphibolites were subdivided into three units based on textural criteria. Unit 1 consists of highly foliated and folded amphibolites and acidic gneiss concordant to and folded along with the foliation of the amphibolite. Unit 2, in the middle part of the section, consists of brecciated amphibolites. Unit 3, at the bottom of the hole, is a weakly deformed zone where magmatic textures are observed in the amphibolites and in associated anorthosites. The amphibolites contain tschermakitic to magnesio-hornblende amphibole, plagioclase, zircon, apatite ± titanite ± Fe-oxide ± quartz. The acidic gneiss consists of garnet, plagioclase, alkali-feldspar, quartz, biotite and zircon. Chlorite, sericite and ilmenite occur as secondary phases. The metamorphic evolution of the amphibolite and acidic gneiss started under amphibolitefacies conditions (Stage I: 670 ± 40°C and 7 ± 1 kbar). Further exhumation took place through low-grade amphibolite-facies (Stage II: 550 ± 50°C and 5.5 ± 1 kbar) to green-schist-facies (Stage III: < 500°C and < 3 kbar) conditions contemporaneous with the development of ductile structures. The late metamorphic evolution of the amphibolite ended under ocean-floor conditions. Oxygen isotope ratios and studies of fluid inclusion indicate that a magmatic water-rich fluid in equilibrium with the igneous protolith predominated during Stage I. During Stages II and IIII low-temperature water-rich fluids of metamorphic origin predominated, with a probable contribution of sea water. Apatite fission-track dating indicates that the amphibolites record two thermal excursions below 120°C. The first took place at c. 113–100 Ma and could be related to Cretaceous rifting. The second was brief, and so did not anneal older tracks; it occurred between 75 and 55 Ma and could be related to the Pyrenean orogeny.

Tectonic implications of exposure of lower continental crust beneath the Iberia Abyssal Plain, Northeast Atlantic Ocean: Geophysical evidence

We present new seismic data from a basement high beneath the southern Iberia Abyssal Plain that appears, from the latest Ocean Drilling Program (ODP) results and indirectly from various seismic observations, to consist of lower continental crustal material. This is a unique opportunity to use seismic profiles and other geophysical evidence to investigate the tectonic process which led to the exhumation of these rocks. We infer that the lower crust was exhumed at the seafloor and then uplifted toward the end of rifting. Our results lead to the following new observations: low‐angle detachment faults, previously reported along the east‐west Lusigal‐12 profile across the southern Iberia Abyssal Plain, penetrate both the 3–10 km thick continental crust and, unusually, the uppermost mantle. Processing of new multichannel seismic reflection profiles across the basement high on which ODP Sites 900, 1067, and 1068 are located reveals that the high is bounded by a previously unsuspected steep, landward dipping normal fault on its east flank. Basement cores from the above ODP sites also reveal that the high is not capped by the previously predicted early syn‐rift sediment but by rocks from the lower continental crust. These unexpected observations are incorporated into a new tectonic model of the development of this part of the west Iberia margin which is also consistent with other geophysical observations. A novel feature of this model is the proposal that the seaward edge of the continental crust is thinned to 3–6 km by a currently poorly understood process. The model implies three stages of deformation: (1) lithospheric extension, principally by symmetric pure shear, which leads to a ∼10 km thick crust in which the lower crust is largely absent over the axial zone and the crust‐mantle boundary forms a shear zone, (2) further thinning and then dissection of the most distal continental crust by seaward dipping, low‐angle normal faults, (3) inception of a high‐angle, landward dipping normal fault that offsets the tectonized crust‐mantle boundary and uplifts the lower crust to the crest of the basement high on which ODP Sites 900, 1067, and 1068 were drilled.

Late Jurassic sedimentation and deformation in the west Iberia continental margin: insights from FMS data, ODP Leg 173

In the Iberia Abyssal Plain, Ocean Drilling Program (ODP) Site 1065 drilled the top of a continental tilted block, penetrating a Middle to Late Jurassic probable pre-rift sedimentary unit. Borehole images of this unit were obtained by the Formation MicroScanner (FMS) logging tool, thus allowing the identification and 3D measurement of two block tilting phases. The last one is an eastward 15° tilt, probably related to the main Early Cretaceous rifting phase, and consistent with the tilted block image on seismic lines. The first tilt, previously unknown, is Late Jurassic in age. The block tilting is 15° to the southeast, and is not associated with any noticeable change in the depositional environment. Both tilting episodes induced sedimentary instabilities, leading to listric faults and slumps. FMS images also showed that the sediments originated from the north (Galicia Bank) during Late Jurassic times.

Deep structure of the ocean‐continent transition in the southern Iberia Abyssal Plain from seismic refraction profiles: The IAM‐9 transect at 40°20′N

We present a crust and mantle velocity structure for the West Iberia passive continental margin derived from a 320‐km‐long wide‐angle seismic profile acquired in the southern Iberia Abyssal Plain. We observe a 170‐km‐wide ocean‐continent transition zone which includes a pair of overlapping peridotite ridges and is bounded by oceanic crust and landward by fault‐bounded blocks of continental crust. The profile lies ∼40 km south of the transect sampled by Ocean Drilling Program (ODP) Legs 149 and 173. The transition zone structure can be divided into an upper layer, 2–4 km thick with velocities of between 4.5 and 7.0 km s−1 and generally a high‐velocity‐gradient (1 s−1), and a lower layer up to 4 km thick with a velocity of ∼7.6 km s−1 and a low‐velocity‐gradient. A weak Moho reflection in this zone was seen only on wide‐angle profiles at an offset of ∼30 km. The upper layer has a distinctly lower velocity than thinned continental crust adjacent to the continental slope. Conversely, the lower layer has too high a velocity to be magmatically intruded or underplated lower continental crust. On the coincident seismic reflection profile, fault‐bounded crustal blocks, identified in unequivocal extended continental crust, are not observed in the transition zone. The upper layer has velocity bounds and gradient similar to oceanic layer 2 observed west of the peridotite ridges, but no oceanic layer 3 velocity structure is present. While magnetic anomalies have been identified within the transition zone, they have not been modeled successfully as seafloor spreading magnetic anomalies, nor do they generally form long linear margin‐parallel features. Finally, ODP boreholes, ∼40 km north of our profile and within the interpreted transition zone, have recovered up to 140‐m‐thick sections of serpentinite and serpentinized peridotites with little evidence of mafic igneous material. We conclude that the transition zone cannot be dominantly composed of either extended continental crust or oceanic crust. Although current melting models predict a considerably thicker crust of decompression melt products, we interpret this region as exposed upper mantle peridotite with little or no synrift extrusive material and limited amounts of synrift material intruded within the serpentinized peridotite.

Drilling reveals transition from continental breakup to early magmatic crust

For the first time in an ocean‐continent transition zone (OCT), drilling has sampled rocks above and below what appears to be a synrift tectonic crust‐mantle contact. Research in the West Iberia OCT is assembling important data on the histories and ages of the basement rocks there. The principal result has been to show that evolution of the margin was dominated by extensional tectonics with only slight evidence of possible synrift melting.A significant preliminary finding of the recently completed Leg 173 of the Ocean Drilling Program (ODP) is that many, if not all, fault blocks underlain by a low‐angle reflector on multichannel seismic profiles under the 5000‐m deep Iberia Abyssal Plain consist of continental crust and are quite thin. The drilling has also shown that lower crust and peridotite became exposed in the OCT between the blocks of continental crust and the first products of oceanic accretion over a zone that appears to be tens of kilometers wide. This supports the hypotheses that predict a broad zone of upper mantle basement beneath the sediments in the development of the West Iberia zone. Preliminary observations of textural and compositional variations of the peridotite from east to west suggest that further studies will document the evolution of the mantle from continental breakup to oceanic accretion.

Quantitative subsidence analysis of the Mesozoic evolution of the Lusitanian basin (western Iberian margin)

Quantitative subsidence analysis of 26 wells in the Lusitanian basin provides new constraints on the western Iberian Mesozoic passive margin development. Backstripped tectonic subsidence curves show a three-fold subdivision of vertical motions from Late Triassic onward. Continental rifting was initiated during the Late Triassic and Early Jurassic. From Middle Jurassic onward a distinct different behaviour is expressed in the subsidence curves for the North and the South Lusitanian basin. During the Middle Jurassic the South Lusitanian basin records a stretching episode with stretching factors of about 1.08, while the North Lusitanian basin typically has a Middle Jurassic hiatus. This different development is also expressed in the Late Jurassic and Early Cretaceous sedimentary sequence when both the North and South Lusitanian basin are subjected to another stretching episode, with a more pronounced development of the southern than of the northern part of the basin. The stretching factors for this last phase are about 1.03 for the northern part and 1.08 for the southern part of the area. This north-south difference during the Middle Jurassic to Early Cretaceous, for which the transition roughly coincides with the location of the Nazaré fault zone, is probably a result of differences in pre-rift crustal composition or thickness. Late Cretaceous sediments are mostly absent in the analysed wells. In the southern part of the basin the absence of the Cretaceous record is a consequence of erosion due to Cenozoic inversion of the basin. The generally low estimates for stretching factors suggest that the analysed eastern part of the Lusitanian basin forms the distal part of the mid-Cretaceous continental breakup. A comparison with subsidence curves of neighbouring basins of Iberia reflects general patterns in Mesozoic basin development and confirms the generally held view that the extension leading to continental breakup migrated from south to north during the Middle Jurassic to Early Cretaceous in West Iberia.

Mantle exhumation at passive margins

Laboratory models of lithosphere necking have been used to study the modes of passive margin formation and related mantle exhumation at continent-ocean boundary. Four-layer models were constructed with sand and silicone putty, to represent the brittle and ductile layers, respectively, of both crust and mantle. It is shown that necking of the whole lithosphere model is nearly symmetrical (pure shear) but that asymmetrical structures (simple shear) develop internally, due to heterogeneous boudinage and/or faulting of brittle layers. Relative movements between brittle layers is accommodated by layer-parallel shear in the ductile layers defining a set of conjugate shear zones. With increasing stretching, lower crust and mantle shear zones become juxtaposed as the lower ductile mantle layer rises up through the separation zone of boudins in the brittle layer. The experimental results are used to propose a general model of passive margin formation leading to mantle exhumation. They are also compared to the situation observed on the west Iberia margin. The exhumation of lithosphere mantle is the result of a bulk pure shear at lithospheric scale. Shearing of exhumed mantle rocks does not correspond to detachment faults cross-cutting the whole lithosphere at the onset of rifting but results from heterogeneous stretching and boudinage of the high-strength sub-Moho mantle.

Stress pattern in Portugal mainland and the adjacent Atlantic region, West Iberia

The Portuguese mainland territory is located close to the Azores‐Gibraltar plate boundary, in a tectonic setting responsible for significant neotectonic and seismic activities. However, few data concerning the present regional lithospheric stress field were available, as testified by recently published maps of stress indicators for the Europe and Mediterranean regions. One of the authors already presented a synthesis on this subject [Cabral, 1993], where geological and geophysical stress indicators were considered. In this paper we introduce new information, mainly a considerable amount of borehole breakout data. The updated data set comprises 32 reliable stress indicators showing a mean azimuth of 145° (standard deviation 21°) for the maximum horizontal stress direction (SHmax). On the average, the geological data are rotated clockwise and the focal mechanism data deviated anticlockwise to that azimuth, while the borehole elongation results are consistent with the mean SHmax trend. These differences in stress trend suggest a regional progressive rotation of the SHmax direction from NNW‐SSE to WNW‐ESE since the upper Pliocene. To estimate stress trajectories, new and published stress indicators in the adjacent Atlantic area and northern Africa were also investigated, showing a very uniform NW‐SE SHmax trend in west Iberia. A high level of horizontal compressive stress acting oblique to the western Portuguese continental margin is inferred and interpreted in view of a proposed regional geodynamical model, of activation of this passive margin, with the nucleation of a subduction zone in the Atlantic SW of Iberia, at the Gorringe submarine bank, which is propagating northward along the base of the continental slope, at the transition between thinned and normal continental crust.

Insight into the nature of the ocean-continent transition off West Iberia from a deep multichannel seismic reflection profile

Research Article| December 01, 1996 Insight into the nature of the ocean-continent transition off West Iberia from a deep multichannel seismic reflection profile S. L. B. Pickup; S. L. B. Pickup 1Southampton Oceanography Centre, Southampton SO14 3ZH, United Kingdom Search for other works by this author on: GSW Google Scholar R. B. Whitmarsh; R. B. Whitmarsh 1Southampton Oceanography Centre, Southampton SO14 3ZH, United Kingdom Search for other works by this author on: GSW Google Scholar C. M. R. Fowler; C. M. R. Fowler 2Department of Geology, Royal Holloway, Egham TW20 0EX, United Kingdom Search for other works by this author on: GSW Google Scholar T. J. Reston T. J. Reston 3GEOMAR, Wischhofstrasse 1-3, D24148 Kiel, Germany Search for other works by this author on: GSW Google Scholar Geology (1996) 24 (12): 1079–1082. https://doi.org/10.1130/0091-7613(1996)024<1079:IITNOT>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation S. L. B. Pickup, R. B. Whitmarsh, C. M. R. Fowler, T. J. Reston; Insight into the nature of the ocean-continent transition off West Iberia from a deep multichannel seismic reflection profile. Geology 1996;; 24 (12): 1079–1082. doi: https://doi.org/10.1130/0091-7613(1996)024<1079:IITNOT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract A high-quality multichannel seismic reflection profile across the West Iberia margin confirms the existence of a 130-km-wide transition zone between tilted continental fault blocks and unequivocal oceanic crust. The zone is characterized by a 1.0–2.5-km-thick seismically unreflective upper basement layer lying over reflective basement that contains major landward-dipping reflectors that mostly truncate against the base of the upper layer and penetrate to depths of 10–19 km below the basement surface, and minor seaward-dipping reflectors. Moho reflections are absent in this zone. We suggest that the unreflective layer represents tectonically exposed upper mantle that has undergone extensive serpentinization enhanced by vigorous seawater circulation. About 40 km farther north the transition zone narrows to 35 km and the unreflective layer is less continuous and widespread. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Models of the development of the West Iberia rifted continental margin at 40°30′N deduced from surface and deep‐tow magnetic anomalies

The ocean‐continent transition (OCT) on nonvolcanic rifted continental margins is important in that it contains evidence concerning the breakup of the continents and the onset of seafloor spreading. The nature of the OCT off western Iberia has recently been attracting attention following seismic and other geophysical studies there and drilling of acoustic basement by Leg 149 of the Ocean Drilling Program. Here we concentrate on the interpretation of a new digital magnetic anomaly chart for the Iberia Abyssal Plain between 39.5° and 42.2°N. The most striking anomaly is a trough which exists immediately east of, and locally parallel to, anomaly J and is closely coincident with a basement peridotite ridge. We conclude from modeling surface magnetic anomalies and a deep‐tow magnetometer profile that seafloor spreading began about 129.9 m.y. ago (Barremian) at a rate of 10.0 mm/yr, consistent with drilling and seismostratigraphic results from the southern Iberia Abyssal Plain. A second feature is the existence of linear low‐amplitude isochron‐parallel magnetic anomalies east of the peridotite‐ridge trough and a clear change in the trend of these anomalies east of about 11°15′W. It is possible to model these anomalies by a series of 7‐ to 30‐km‐wide weakly magnetized crustal blocks of about the same thickness as the oceanic crust. The west‐to‐east anticlockwise change in trend at 11°15′W suggests either a major change in stress regime and/or in the type of magnetic anomaly source. We speculate that the region between the peridotite ridge and 11°15′W represents a transitional crust whose formation was dominated by the same stress regime which accompanied eventual seafloor spreading. We explain the change in trend at 11°15′W by a model featuring a rift which propagated through continental crust from south to north. We consider three scenarios for the formation of the transitional zone crust; first, continental crust is surrounded and impregnated by intrusive and extrusive material, formed from passive upwelling of magma created by the limited adiabatic decompression partial melting which occurs as the two continental lithospheric plates first begin to separate, second, such crust is surrounded by unroofed upper mantle material, or third, the zone is the product of ultraslow seafloor spreading. Present evidence tends to support the first scenario. In this scenario, the top of the asthenosphere eventually becomes shallow enough to enable magma to penetrate the thinnest continental crust, fill the space caused by additional extension, and form the transitional crust, already described, over a broad zone at least several tens of kilometers wide. At breakup, upper mantle rocks become exposed on the seafloor and undergo extensive serpentinization. In a final stage we envisage focusing of the igneous activity leading to the onset of seafloor spreading, initially producing thin oceanic crust because of a restricted melt supply. The width of continuous technically extended continental crust in the southern Iberia Abyssal Plain is less than was previously supposed.

ODP drills the West Iberia rifted margin

Leg 149 of the Ocean Drilling Program drilled a transect of basement holes across the ocean‐continent transition (OCT) of the rifted continental margin off the west coast of Portugal. The principal objective was to sample a series of basement highs beneath the Iberia Abyssal Plain, which were thought to span the transition from the oldest oceanic crust to a peridotite ridge separating oceanic from extended continental crusts to a broad region of highly‐extended continental crust.Drilling demonstrated that the late rift‐stage exposures of peridotite at the seafloor are more laterally extensive than previously thought; peridotite was found on two highs 19 km apart. From the region expected to be extended continental crust, we cored 57 m of metagabbro basement whose continental or oceanic affinities are not yet clear. This rock may be Hercynian in age, and therefore part of the continental crust that was rifted to form this margin, or it may have been emplaced, uplifted, and exposed during rifting some 125 m.y.a. At our most landward site, Tithonian sediments, deposited about 20 m.y. before the onset of seafloor spreading on this segment of margin, are interpreted to overlie extended continental crust. The results of the leg will shed new light on the mechanisms by which upper mantle and perhaps lower crustal rocks are exposed at the seafloor during the late stages of continental breakup.

Ocean-continent boundary in the Iberia Abyssal Plain from multichannel seismic data

The Ocean-Continent Boundary of the West Iberia margin is marked by a basement ridge trending N-S. Four segments of this ridge are recognized, each of them being progressively offset westward from 40°N to 43°N. Because the setting and seismic character of the ridge in the Iberia Abyssal Plain are similar to those of the Galicia margin ridge, which is made of serpentinized peridotite, we think that the southern segments of the ridge are also made of the same mantle material. The segmentation of the ridge suggests that the northward propagation of the continental break-up during the North Atlantic opening in Early Cretaceous times was discontinuous, each segment possibly corresponding to a propagation step. East of the ridge, the basement of the whole Iberia Abyssal Plain consists of highly thinned continental crust locally resting on a seismic reflector that resembles the S reflector previously recognized off Galicia. By analogy with the Galicia margin, we propose that the tilted crustal blocks lay on serpentinized peridotite derived from the upper mantle, the S reflector corresponding to the contact between crustal rocks and serpentinite.

SONGS OF A WAYFARING LAD

Summary. Trade languages are an indispensable mechanism of communication and acculturation in direct and long term trade relationships. In such cases, the aim of this paper is to suggest that Lusitanian, the old Indoeuropean language spoken in West Iberia, arrived in this way from the Atlantic region in the Late Bronze Age, together with technical improvements and a new ideology that deeply influenced the local population, which preserved these cultural features unchanged until the Roman conquest.