EUR/EC22 - L'embouchure de Le Rhône EarthCache

Histoire géologique de la Vallée du Rhône

La vallée du Rhône est un bassin sédimentaire, bordé à l’ouest par le Massif Central et à l’est par les massifs alpins. Il s'étend du bassin de la Bresse au nord à la mer Méditerranée au sud, et couvre au passage les bassins du Bas-Dauphiné, de Crest, de Valréas, d' Avignon... La vallée du Rhône a connu  différentes phases de formation : marines, continentales, et fluviales, accompagées de mouvements tectoniques consécutifs à la surrection des Alpes. Elle existe géologiquement depuis le Miocène. Avant le Miocène (- 23.5 à - 5.3 Ma) Les matériaux sédimentaires du Mésozoïque (-245 Ma à - 65 Ma) datant des périodes Trias et Jurassique ont été recouverts par les sédiments du Crétacé et du Cénozoïque.  Quelques affleurements disséminés dans la Vallée du Rhône sont visibles: ·         Trias (- 245 Ma à - 205 Ma):  affleurements  dans la région de Valence.  ·         Jurassique ( - 205 Ma à - 135 Ma):  affleurements dans le Massif de Suzette-Gigondas à l’ouest d’Orange, dans la montagne de Crussol près de Saint-Péray. ·         Crétacé (- 335 Ma à - 65 Ma): A l'étage Urgonien, la mer  dépose des couches importantes de sédiments calcaires  (400 m), qui vont former les massifs crétacés de Marsanne, , du Vercors, des Alpilles,  du Lubéron. A l'Aptien, elle dépose différents calcaires et marnes dans la région de Vaison, Apt et des grés calcaero-marneux dans le Tricastin.  A la fin du crétacé la mer se retire, on entre dans une période continentale jusqu’au Miocène. Cette régression s'accompagne de dépôts sédimentaires détritiques fluviatiles, lacustes ou saumâtres compartimentés à la morphologie des différents bassins. Cénozoïque ou ère tertiaire ( - 66 Ma à - 1.8 Ma)  Surrection des Alpes et plissements Parallèlement aux phases de régressions et de transgressions marines,  qui vont se succéder, des plissements transversaux, de direction est-ouest vont  se mettre en place. Ils résultent des poussées des différentes phases de formations alpines au cours de l'ère tertiaire dans toute la Vallée du Rhône. ·         Au sud de Donzère, et en rive droite du Rhône, ce sont des plis pyrénéo provençaux à l’éocène supérieur. ·         En rive gauche du Rhône, des plis plus importants, forment les reliefs du Ventoux, du Lubéron, des Alpilles. Ils sont liés à la phase pyrénéo-provençale, mais à une période différente.(Oligocène,  fin Miocène) ·         A l’ouest du Ventoux, se forme le massif de Suzette-Gigondas avec les dentelles de Montmirail.

Evolution sédimentaire Jusqu'au Miocène, l'évolution sédimentaire est hétérogène (fluviatile, lacustre ...), variable selon les endroits:  ·         Calcaires lacustres, marnes dans le bassin de Crest, d’Apt, du Tricastin. ·         Dépôts détritiques saumâtres dans le bassin de Valréas. ·         Dépôt sédimentaires détritiques sables fluviatiles,calcaires lacustres, un peu partout ·         Calcaires marneux,  grès, marnes grises dans les bassins d'effondrement.  A partir du Miocéne, la mer revient, l'évolution sédimentaire va devenir  homogène.

Miocène (- 23.5 Ma à - 5.3 Ma)

Au Miocène, il y a 24 Ma d'années, la plaque africaine à l’origine de la formation des Alpes, change de cap, les Alpes poursuivent leur surrection, mais le domaine rhodanien jusque là en compression, subit  une extension et s’affaisse.  La mer Méditerranée envahit cette dépression progressivement jusqu'à Lyon et au delà. Au Burdigalien (- 20 Ma), elle progresse, jusqu’au bassin de Crest, puis elle communique avec la Savoie, la Suisse pour  rejoindre la mer de l’Europe Centrale,  et envahit le Bas-Dauphiné. De nombreux cours d’eau qui descendent des reliefs des Alpes en surrection charrient vers la mer, dans les zones deltaïques, de grandes quantités de matériaux détritiques, graviers, sables et argiles qui vont se consolider en conglomérats et en grès argilo-calcaires appelés molasses. Les cours d’eau qui descendent du  Massif Central charrient des matériaux, mais en plus petite quantité. Au cours des années, les creux et reliefs marins qui forment les bassins miocènes  sont comblés par des centaines de mètres d’épaisseur de sables, d’argiles et de marnes. La mer recule peu à peu. A la fin du Miocène, la série Miocéne constitué de couches sédimentaires différentes (cailloutis, marnes et argiles alluvionnaires ...) va atteindre 1000 mètres. Ces dépôts remplissent  les bassins du Bas-Dauphiné, de Crest, de Visan-Valréas, de Carpentras et  du sud du Lubéron. Ils forment aujourd’hui les collines de Valréas,Visan, Vinsobres, Rasteau, Cairanne… Suite à des mouvements tectoniques de - 5.8 Ma à 5.3 Ma , le mer Méditerranée se ferme au niveau du détroit de Gibraltar et  s’assèche partiellement.  Vers 5.3 Ma , le passage s'ouvre à nouveau entre la Méditerranée et l'Atlantique, le niveau marin remonte et un bras de mer envahit les vallées qui vont se combler d'alluvions jusqu’au sud de Lyon.  Des marnes de teintes bleues se déposent, elles affleurent à l’est de Crozes-Hermitage, à Vinsobres, Rasteau. Le Miocène se termine par une phase d’émersion consécutive aux mouvements tectoniques qui affectent la région.

Pliocène (- 5.3 Ma à -1.8 Ma)

Vers -  3 Ma,  la formation des Alpes se termine. La mer se retire, de nombreux lacs se forment, puis se comblent progressivement. Le Rhône et ses affluents vont charrier des masses considérables de  matériaux détritiques, qui vont former de hautes terrasses de Châteauneuf-du-Pape et de Lirac. Quaternaire ( - 1.8 Ma à - 10 000 ans) Au cours des deux derniers millions d’années la tectonique alpine est réduite. Les Alpes, les Pyrénées, les Vosges et le Massif Central se couvrent de glaciers pendant les différentes périodes glaciaires.  Au Villefranchien (- 1.8 Ma à - 700 000 ans), les fleuves puissants charrient des volumes considérables de matériaux (galets, graviers, sables arrachés aux reliefs), que l’on retrouve jusqu’aux abords de Montpelier sous forme de nappes de galets essentiellement alpins. Les périodes glaciaires vont former de grandes terrasses étendues, riches en cailloutis grossiers qui vont s’étager à différentes altitudes.  Cette sédimentation alluviale  va continuer jusqu’à nos jours. Elle forme le terroir des vignobles. On retrouve ces colluvions caillouteux dits Villefranchiens au pied du Massif des Dentelles de Montmirail, de Séguret à Gigondas, Vacqueyras,, des villages de Rasteau, Cairanne et des alluvions quaternaires du Rhône à Châteauneuf-du-Pape, Tavel et Lirac. Les vignobles On distingue deux zones: ·         La zone septentrionale cristalline: Les terroirs viticoles de la rive droite sont constitués par les terrains primaires qui  bordent le Massif-Central. Le vignoble du Diois repose sur des sols calcaires du Jurassique . ·         La zone méridionale calcaire: Cette zone est représentative de la formation du bassin sédimentaire de la Vallée du Rhône décrite ci-dessus. les terroirs viticoles sont constitués de terrains d'âge Crétacé et Tertiaire, et d' alluvions fluviatiles charriées par le Rhône et ses affluents. Les terroirs sont variés. Le vignoble occupe des coteaux et des terrasses.

L'eau, portant des roches, atteint la nappe phréatique, reçoit de l'eau de la zone saturée, des affluents et des pluies, augmentant le volume.
c) glisser

The Rhone valley is a sedimentary basin, bordered to the west by the Massif Central 

and to the east by the Alpine massifs. It extends from the Bresse basin in the north 

to the Mediterranean Sea in the south, and covers the basins of Bas-Dauphiné, Crest, 

Valréas, Avignon ...

The Rhone valley has undergone various phases of formation: marine, continental, 

and fluvial, accompanied by tectonic movements following the uplift of the Alps.

It exists geologically since the Miocene.

Before the Miocene (- 23.5 to - 5.3 Ma)

Mesozoic (-245 Ma to -65 Ma) sedimentary materials from the Triassic and Jurassic 

periods were covered by the Cretaceous and Cenozoic sediments. 

Some scattered outcrops in the Rhone Valley are visible:

Triassic (- 245 Ma - 205 Ma): outcrops in the Valencia region.

· Jurassic (- 205 Ma - - 135 Ma): outcrops in the Suzette-Gigondas Massif west of Orange,

 in the Crussol mountain near Saint-Péray.

· Cretaceous (-335 Ma to -65 Ma): On the Urgonian level, the sea deposits important 

layers of calcareous sediments (400 m), which will form the Cretaceous massifs of 

Marsanne, Vercors, Alpilles, Lubéron .

In the Aptian, it deposits various limestones and marls in the region of Vaison, 

Apt and calcaero-marly sandstones in the Tricastin.

 At the end of the Cretaceous the sea withdraws, one enters a continental period until 

the Miocene. This regression is accompanied by fluviatile, lacustrine or brackish detrital 

sedimentary deposits compartmentalised to the morphology of the different basins.

Cenozoic or tertiary era (- 66 Ma to - 1.8 Ma)

Alps and folds

In parallel with the successive phases of regressions and transgressions of the sea, 

transverse folds of east-west direction will be established.

They result from the thrusts of the different phases of alpine formations during the 

tertiary era throughout the Rhone Valley.

· To the south of Donzère, and on the right bank of the Rhone, they are Pyrenean folds of 

Provencale to the Upper Eocene.

· On the left bank of the Rhone, the most important folds form the reliefs of the Ventoux, 

the Luberon and the Alpilles. They are linked to the Pyreneo-Provencal phase, but to a 

different period (Oligocene, late Miocene)

· To the west of the Ventoux, the massif of Suzette-Gigondas forms with the laces of

 Montmirail.

Sedimentary evolution

Until the Miocene, the sedimentary evolution is heterogeneous (fluviatile, lacustrine ...),

 variable according to the places:

· Lacustrine limestones, marls in the Crest, Apt, Tricastin basin.

· Brine detrital deposits in the Valréas basin.

· Detrital sedimentary deposits fluvial sands, lacustrine limestones, everywhere

· Marly limestones, sandstones, gray marls in collapsing basins.

 From the Miocene, the sea returns, the sedimentary evolution will become 

homogeneous.

Miocene (-23.5 Ma to -5.3 Ma)

In the Miocene, twenty-four million years ago, the African plate at the origin of the 

formation of the Alps changed course, the Alps continued their uplifting, but the Rhone 

domain, until then under compression, underwent an extension, sags.

The Mediterranean Sea invaded this depression gradually to Lyons and beyond.

In Burdigalien (-20 Ma), it progresses to the Crest basin, then communicates with Savoy,

Switzerland to reach the sea of ​​Central Europe, and invades the Bas-Dauphiné.

Numerous streams descending from the reliefs of the Alps in an upward direction carry 

large quantities of detrital materials, gravels, sand and clays towards the sea, in the 

deltaic zones, which will consolidate into clay and limestone conglomerates and 

sandstones called molasses .

The rivers flowing from the Massif Central carry materials, but in smaller quantities.

Over the years, the hollows and reliefs that form the Miocene basins are filled with 

hundreds of meters of sand, clay and marl. The sea gradually recedes.

At the end of the Miocene, the Miocene series made up of different sedimentary 

layers (pebbles, marls and alluvial clays ...) will reach 1000 meters.

These deposits fill the basins of Bas-Dauphiné, Crest, Visan-Valréas, Carpentras and southern 

Lubéron. Today they form the hills of Valréas, Visan, Vinsobres, Rasteau, Cairanne ...

Following tectonic movements of - 5.8 Ma to 5.3 Ma, the Mediterranean Sea closes in 

the Straits of Gibraltar and partially dries.

Towards 5.3 Ma, the passage opens again between the Mediterranean and the Atlantic,

the sea level goes up and an arm of sea invades the valleys that will fill alluvial to the 

south of Lyon.

Marlins of blue hues are deposited, they are exposed to the east of Crozes-Hermitage, 

Vinsobres, Rasteau.

The Miocene ends with an emergence phase following the tectonic movements that 

affect the region.

Pliocene (-5.3 Ma to -1.8 Ma)

Towards - 3 Ma, the formation of the Alps ends.

The sea recedes, many lakes are formed, then gradually fill up.

The Rhone and its tributaries will carry considerable masses of detrital materials, 

which will form high terraces of Chateauneuf-du-Pape and Lirac.

Quaternary (- 1.8 Ma to - 10,000 years)

During the last two million years alpine tectonics is reduced. The Alps, the Pyrenees, 

the Vosges and the Massif Central are covered with glaciers during different glacial

periods.

In the Villefranchien (- 1.8 Ma to - 700 000 years), the powerful rivers carry 

considerable volumes of materials (pebbles, gravels, sand removed from the reliefs), 

which are found as far as Montpelier in the form of pebble sheets mainly alpine.

The glacial periods will form large large terraces, rich in coarse pebbles that will rise to 

different altitudes.

This alluvial sedimentation will continue to this day. It forms the soil of the vineyards.

One finds these stony colluvions called Villefranchiens at the foot of the Massif of the 

Dentelles de Montmirail, from Séguret to Gigondas, Vacqueyras, from the villages of 

Rasteau, Cairanne and quaternary alluviums from the Rhône to Châteauneuf-du-Pape, 

Tavel and Lirac.

The vineyards

There are two zones:

· The crystalline northern zone:

The wine-producing terroirs of the right bank are constituted by the primary lands bordering the Massif Central.

The Diois vineyard rests on limestone soils of the Jurassic.

· The southern limestone zone:

This zone is representative of the formation of the sedimentary basin of the Rhone Valley described above. the vineyards are made up of Cretaceous and Tertiary lands and alluvial deposits carried by the Rhone and its tributaries. The terroirs are varied. The vineyard occupies hillsides and terraces.

Hydrogeological context of the river:

Geological action of river waters

River formation

source → arroyo → stream → River

The water, by wearing down the rocks, reaches the water table, receiving water from the saturated zone, the tributaries and the rains, increasing its volume.

Action of the rivers

There are two types:

Dissolution of rocks: Rocks formed by salts with ionic bonds are dissolved (chemical action).

Fragmentation of rocks: The rocks are broken into pieces by the force of the water (physical action).

Forms of transport

Soon after the action of the rivers, the materials are transported, being able to be of three distinct ways:

in solution → transport of ions

in suspension → transport of molecules and small particles (eg clay)

in hauling → transport of heavy materials, from the bottom. being this transport in two ways:

by bearing (without obstacle, if the bottom is smooth)

by jumping (with obstacle, if the bottom is not smooth)

In the two cases of entrainment the pebbles are rolled (rounded blocks less than 25cm in diameter).

River Stages (or Age)

Location

By the location and action exerted by the river we can observe three phases:

juvenile → descends on the mountain and occurs more intemperismo in depth than in 

the lateral ones

mature → goes down the valley and occurs more weathering in the sides than in depth

senile → flows through the plain and practically does not occur weathering but 

deposits of materials coming from the action of the river

Having a river completed such a cycle, that is, when its energy is such that it allows only the simple flow of the waters, whose erosive power is diminished to the maximum,

it is said that this river has reached its equilibrium profile. Erosion progresses very slowly  only at the headwaters of the river, where the gradient is most pronounced. 

The level at which the erosive work ceases is called the base level. 

It is evident that the base level of all the rivers that are drained into the ocean is the 

very level of this. If a river flows into a lake, its level will be the temporary base level 

of the river in question, because the lake's destination is to be clogged by continuous 

sedimentation, and later eroded by the river itself draining it to the seas.

To claim a discovery in this EarthCache, the coordinates were provided.

Here, collect the data you need to answer the following six (6) questions

1-In the downward direction towards the sea, on the right side of the GZ what exists?

a) A Port

b) A saline

c) A bridge

d) A Marina

2- On the margin side, how wide is its margin?

a) less than 500 meters

b) between 501 and 590 meters

c) between 591 and 680 meters

d) between 681 and 775 meters

e) more than 776 meters

3- In the field, it is possible to identify in which stage the river finds?

a) Young

b) mature

c) senile

4- What is the stage of the Rio course in this place?

a) superior

b) medium

c) lower

5- The name Rhône means

a) renverser

b) tourner vivement

c) rivière vivante

d) tourner brusquement

6- Is the transport of rock / sediment in the place mainly made by ...?

the solution

b) suspension

c) drag

História geológica do Vale do Ródano

O vale do Ródano é uma bacia sedimentar, limitada ao oeste pelo Maciço Central e a 

leste pelos maciços alpinos. Estende-se da bacia do Bresse no norte até o Mar 

Mediterrâneo no sul e cobre as bacias de Bas-Dauphiné, Crest, Valréas, Avignon ...

O vale do Ródano passou por várias fases de formação: marinha, continental e fluvial, 

acompanhada de movimentos tectônicos após a elevação dos Alpes. 

Existe geologicamente desde o Mioceno.

Antes do Mioceno (- 23,5 a - 5,3 Ma)

Os materiais sedimentares mesozoicos (-245 Ma a -65 Ma) dos períodos Triássico 

e Jurássico foram cobertos pelos sedimentos do Cretáceo e do Cenozóico. 

Alguns afloramentos dispersos no Vale do Ródano são visíveis:

Triássico (- 245 Ma - 205 Ma): afloramentos na região de Valência.

· Jurassic (- 205 Ma - - 135 Ma): afloramentos no Maciço de Suzette-Gigondas a oeste de

 Orange, na montanha de Crussol, perto de Saint-Péray.

· Cretáceo (-335 Ma a -65 Ma): no nível urgoniano, o mar deposita grandes camadas de 

sedimentos calcários (400 m), que formarão os macios do Cretáceo de Marsanne, 

Vercors, Alpilles, Lubéron .

No Aptian, deposita vários calcários e margas na região de arenitos Vaison, Apt e calcaero-marly no Tricastin.

No final do Cretáceo, o mar se retira, entra um período continental até o Mioceno. 

Esta regressão é acompanhada de depósitos sedimentares detritais fluviais, lacustres ou 

salobrais compartimentados à morfologia das diferentes bacias.

Cenozoico ou terciário (- 66 Ma a - 1,8 Ma)

Alpes e dobras

Paralelamente às fases sucessivas de regressões e transgressões do mar, serão colocadas 

juntas transversais, de direção leste-oeste.

Eles resultam dos impulsos das diferentes fases das formações alpinas durante a era 

terciária ao longo do Vale do Ródano.

· Ao sul de Donzère, e na margem direita do Ródano, são pregas pirenaicas de 

Provencale para o Eoceno Superior.

· Na margem esquerda do Ródano, as dobras mais importantes formam os relevos do 

Ventoux, do Luberon e dos Alpilles. Eles estão ligados à fase pirenaico-provençal, 

mas a um período diferente (Oligoceno, Mioceno tardio)

· Ao oeste do Ventoux, o maciço de Suzette-Gigondas se forma com os laços de 

Montmirail.

Evolução sedimentar

Até o Mioceno, a evolução sedimentar é heterogênea (fluviatile, lacustre ...), 

variável de acordo com os lugares:

· Calcários lacustres, margens na bacia Crest, Apt, Tricastin.

· Depósitos detritos salgados na bacia de Valréas.

· Depósitos sedimentares detentários, areias fluviais, calcários lacustres, em quase

 todos os lugares

· Calcários marinhos, arenitos, margens cinzentas em bacias em colapso.

 Do Mioceno, o mar retorna, a evolução sedimentar se tornará homogênea.

Mioceno (-23,5 Ma a -5,3 Ma)

No meio do Mioceno, vinte e quatro milhões de anos atrás, a placa africana na origem 

da formação dos Alpes mudou de direção, os Alpes continuaram a elevar-se, mas o 

domínio de Rhone, até então sob compressão, passou por uma extensão, afundamentos.

O Mar Mediterrâneo invadiu essa depressão gradualmente para Lyon e além.

Em Burdigalien (-20 Ma), progride para a bacia Crest, depois se comunica com Savoy, 

Suíça para chegar ao mar da Europa Central e invade o Bas-Dauphiné.

Numerosos fluxos que descem dos relevos dos Alpes em direção ascendente carregam 

grandes quantidades de materiais detríticos, cascalhos, areia e argilas em direção ao 

mar, nas zonas deltaicas, que se consolidarão em conglomerados de argila e calcário e 

arenitos chamados melaço .

Os rios que fluem do Massif Central carregam materiais, mas em quantidades menores.

Ao longo dos anos, as cavidades e relevos que formam as bacias do Mioceno são 

preenchidos com centenas de metros de areia, argila e marga. O mar gradualmente 

recua.

No final do Mioceno, a série do Mioceno composta de diferentes camadas sedimentares (pedras, margas e argilas aluviais ...) chegará a 1000 metros.

Estes depósitos enchem as bacias de Bas-Dauphiné, Crest, Visan-Valréas, Carpentras e Lubéron do sul. Hoje eles formam as colinas de Valréas, Visan, Vinsobres, Rasteau, 

Cairanne ...

Após movimentos tectónicos de - 5,8 Ma a 5,3 Ma, o Mar Mediterrâneo fecha no Estreito de Gibraltar e seca parcialmente.

Ao redor de 5.3 Ma, a passagem abre novamente entre o Mediterrâneo eo Atlântico, o nível do mar subiu e um braço de mar invade os vales que irão preencher com o 

aluvim ao sul de Lyon.

Marlins de tons azuis são depositados, estão expostos ao leste de Crozes-Hermitage, Vinsobres, Rasteau.

O Mioceno termina com uma fase de emergência seguindo os movimentos tectónicos que afetam a região.

Plioceno (-5,3 Ma a -1,8 Ma)

Em direção a - 3 Ma, termina a formação dos Alpes.

O mar recua, muitos lagos são formados, depois gradualmente se enchem.

O Rhone e os seus afluentes terão massas consideráveis ​​de materiais detritais, que formarão grandes terraços de Chateauneuf-du-Pape e Lirac.

Quaternário (- 1.8 Ma a - 10.000 anos)

Durante os últimos dois milhões de anos, a tectônica alpina é reduzida. Os Alpes, os Pirenéus, o Vosges e Maciço Central está coberta por geleiras durante as várias eras glaciais.

Em Villefranchien (- 1,8 Ma - 700 000 anos), os rios poderosos transportar grandes  volumes de materiais (seixos, cascalho, areia rasgado de relevos), que se encontra para a periferia da Montpelier formar camadas de calhau principalmente alpino.

eras glaciais vão formar grandes terraços folhetos, ricos em cascalho grosso que vai cambalear em diferentes altitudes. 

Esta sedimentação aluvial continuará até hoje. Forma o solo das vinhas.

Encontramos estes colluvium pedregoso chamado Villefranchiens ao pé do Massif des Dentelles, Séguret Gigondas, Vacqueyras ,, Villages Rasteau, Cairanne e 

Rhône-Quaternário aluvião em Châteauneuf-du-Pape, Tavel e Lirac. 

As vinhas

Existem duas zonas:

· A zona norte cristalina:

Os terrários produtores de vinhos da margem direita são constituídos pelas terras 

primárias que fazem fronteira com o Maciço Central.

A vinha de Diois repousa em solos calcários do Jurássico.

· A zona do calcário do sul:

Esta zona é representativa da formação da bacia sedimentar do Vale do Ródano 

descrita acima. os terroirs são compostas por razões de idade Cretáceo e Terciário, 

e aluvião fluvial transportados pelo Rhone e seus afluentes. Os terrários são variados. 

A vinha ocupa encostas e terraços.

Para reivindicar uma descoberta neste EarthCache, as coordenadas foram fornecidas.

Aqui, colete os dados que você precisa para responder às seguintes seis (6) perguntas

1-No sentido descendente rumo ao mar, do lado direito do GZ o que existe?

a)       Um Porto

b)       Uma salina

c)       Uma ponte

d)       Uma Marina

2- No lado da margem, qual a largura da sua margem?

a) menos de 500  metros

b) entre 501 e 590 metros

c) entre 591 e 680 metros

d) entre 681 e 775 metros

e) mais de 776 metros

3- No terreno, é possível identificar em que estágio o rio encontra?

a) Jovem

b) maduro

c) senil

4- Qual a etapa do curso do Rio neste local?

a) superior

b) médio

c) inferior

5- O nome Rhône significa

a) renverser 

c) rivière vivante

d) tourner brusquement

6- O transporte de rocha / sedimento no local é feito principalmente por ...?

a) solução

b) suspensão

c) arrastar