Castillo del Morro Earthcache EarthCache

Castillo del Morro is the prominent fortress visible from Habana Vieja and all the Malecón. You are currently standing on the upthrow side of a fault!

Introduction:

Morro Castle (Spanish: Castillo de los Tres Reyes Magos del Morro), named after the three biblical Magi, is a fortress guarding the entrance to Havana bay designed by Juan Bautista Antonelli. It was initially constructed in 1589 in response to raids on Havana and protected the mouth of the harbor with a chain(!) being strung out across the water to the fort at La Punta.

You can visit the castle anytime but to tour around inside you’ll need to pay a small fee of 5 CUP for locals or 5 CUC for foreigners. Below the castle, you’ll find a restaurant located in an old battery called Los Doce Apóstoles and a small snack bar in the castle itself if you’re in need of refreshment. Several times per day, a guide will offer a tour of the old lighthouse built in 1844-45 where you can climb up the spiral staircase and get a glimpse of the French built crystal mechanism that uses prisms to focus light into concentrated beams that reach 33km out to sea and 60km out to airplanes; the electric system was added in 1945.

Inside you’ll find various exhibits containing relics from the past and a fairly well-detailed history of the (successful) British siege in 1762. Other sights include latrines featuring chutes leading directly into the ocean and a prison showcasing shark holes(!) through where prisoners were tossed as a form of execution.

Geology:

Habana is located on the western end of an anticlinorium that extends from Habana to Matanzas, a distance of approximately 100 kilometers. The structure is complicated by minor folds and east of Habana Bay by intrusions. The column consists of Upper Cretaceous, Eocene, Oligocene with two members, undifferentiated Upper Tertiary, and Pleistocene or Recent. The Cretaceous is exposed in a belt 10 kilometers wide along the axis of the anticlinorium, and is flanked by the Tertiary on the north, west, and south sides.

The low-dipping Tertiary lying unconformably on the steeply dipping Cretaceous evidences extensive post-Cretaceous-pre-Upper Eocene folding and erosion. Since Eocene time the principal events have been elevations and submergences with one minor period of folding. Habana Bay is a drowned valley in the Cretaceous connected with the ocean by a channel through faulted Tertiary limestone.

The first knowledge of the geology of Habana was recorded by Humboldt who visited Cuba in 1803 and again in 1805. He recognized the continuity of an extensive formation in various parts of the island which later writers have denominated "Cavernous Limestone," "Porous Limestone", and "Yumuri Limestone." To this widespread series, Humboldt gave the name "Güines Limestone" from its occurrence north of Güines in Habana Province. Arguing solely from lithologic similarity, Humboldt believed this formation to be Jurassic and not Tertiary in age as it now has been found to be.

One of the most illuminating expositions of the geology of Habana and environs was written by D. Pedro Salterain. Salterain correctly observed the recently consolidated beach material which he termed "arrecifes" (reef rocks). He divided this from the underlying beds which he considered post-Pliocene. He recorded the Güines limestone in Habana and assigned it to the Miocene. It is a matter of interest to note that Salterain made the mistake that has been duplicated by nearly all subsequent workers in correlating the Upper Eocene west of the bay of Habana with the Oligocene on the east side where Morro Castle resides.

Salterain's most valuable contribution was his very strong belief in the presence of the Cretaceous in Habana, though he stated that his belief was not based on paleontological data. Abundant evidence substantiating this belief is now known. He also made the valuable observation that asphalt occurs with the Cretaceous and associated igneous rocks. Hill noted what he termed the "older limestone" in Habana which he stated was Eocene, Miocene, or Pliocene in age. He also called attention to the anticlinal structure of the Habana area.

Though there is but little faulting within the Tertiary, a fault with a throw of about 200 feet is marked by the channel of Habana Harbor. The east side was uplifted, making the steep cliff on which Morro Castle is located (Fig. 5). This uplift is a part of the general arching of the Habana-Matanzas anticline.

This image depicts the entrance to Habana Harbor. El Morro is on the right and the Malecon on left at 10 feet elevation. El Morro is on the upthrow side of a fault.

Topography:

The topography of Habana and vicinity is one of low relief. A ridge, with an elevation of some 200 feet, enters the area from the east, parallels the coast, and ends abruptly in a high cliff at Morro at the entrance to Habana Harbor. The same structure reappears about 4 kilometers west of the harbor in a hill on which the University of Habana and Castillode Principe are located. At this point the structure makes a sharp turn to the south and continues through the suburbs of Ceiba and Puentes Grandes in a wide arc to Marianao, a distance of about 7 kilometers. On the seaward slope of this ridge the newer suburbs of Habana (Ceiba and Vedado) and the little towns Quemado and Marianao are situated. At Marianao, the structure turns southwestward and passes out of the area.

In the area between Morro and the university, only a low rise marks the location of the structure that to both the east and the west forms a comparatively high ridge. It is on this low, interrupted part of the ridge, that Habana proper is situated. South of Habana are several low, elongated, east-west hills on which are located several suburbs of the capital, the principal ones being Jesus del Monte, Vibora, and Cerro. Reference to the accompanying map shows that Habana and its suburbs are distributed in the form of a horseshoe with Habana at the toe on the north. The intervening area is low and swampy in places and is largely open pasture land. Several narrow terraces occur in the area under discussion. These range from below sea level to an elevation of about 200 feet.

Upper Cretaceous – Habana Formation:

The oldest formation exposed in Habana is Upper Cretaceous in age. It is a series of shales, marls, chalks, loosely consolidated gravels, conglomerates, and calcareous sandstone. Ruttens described the series and named it the "Older Habana formation" and placed it in the Eocene, Oligocene, and possibly "older Miocene," because of the occurrence of Nummulinae, Orthophragminae, and Lepidocyclinae. Examination of the area has produced abundant evidence favoring the view expressed by Salterain. DeGolyer states "at Luyano in the vicinity of Havana .... as well as at other places, a series of white marls, shales, limestones and grits outcrop" and he gave them the name "Luyano Marls." The Cretaceous outcrop at Luyano includes three of the four members: lime gravels, cone sandstone, and dirty shales. This formation is of wide extent and is well developed in all the provinces of Cuba.

The exposure in Habana is but the western end of a long belt 6 to 7 miles in width, that extends with but one interruption from Habana to the city of Matanzas. The greatest development of the Upper Cretaceous known in Cuba is from the city of Habana southward where it attains a thickness of perhaps 7,000 feet. It is therefore named the "Habana formation." In the western half of the area under discussion the lower measures of the Habana formation are a thick series of light gray and brown, limy shales and marls. Wells within this terrane indicate that the unweathered shales are blue in color and contain much pyrite and organic material. Thus far they are known to contain but few fossils. These shales lie directly under a thick series of interbedded sandstones and shales that in private reports have been termed "El Cano shales" from their occurrence near the town of that name. In the El Cano member thus far few fossils have been found.

To log this Earthcache:

Please send the answers to the following questions at the same time you log the cache. If you believe you won’t have internet, please wait and log your cache when you have a connection to ensure the log and answers are sent simultaneously to aid in management. Any logs found without accompanying answers will be deleted.

Questions:

1. You are standing on the upthrow side of a fault. Have a look to the west at Habana and estimate the difference in height between El Morro Castle and the Malecon to determine how far your side has shifted. Round to the nearest 5ft.
2. Using the map, which epoch corresponds with the formation El Morro Castle is built upon?

Bonus:

1. How many cannonballs are stacked up at GZ?
2. Who first wrote about geology in Habana?
3. In what year was the lighthouse added to El Morro Castle?
4. How many cannon are aligned facing the harbor in front of Los Doce Apóstoles
5. What appears to be holding up the torch sconces (lamps) on the walls of the castle?
6. Submit a picture!

Resources:

• https://en.wikipedia.org/wiki/Morro_Castle_(fortress)
• https://en.wikipedia.org/wiki/Faro_Castillo_del_Morro
• https://es.wikipedia.org/wiki/Castillo_de_los_Tres_Reyes_Magos_del_Morro
• http://www.redciencia.cu/geobiblio/paper/1934_Palmer_RH_The%20Geology%20of%20Habana,%20Cuba,%20and%20Vicinity.pdf
• http://www.castles.nl/el-morro-castle
• http://www.earthmagazine.org/article/travels-geology-journeying-through-cubas-geology-and-culture