[Senate Treaty Document 106-39]
[From the U.S. Government Publishing Office]

106th Congress                                              Treaty Doc.
 2d Session                                                   106-39









 July 27, 2000.--Treaty was read the first time, and together with the 
accompanying papers, referred to the Committee on Foreign Relations and 
            ordered to be printed for the use of the Senate.


79-118                     WASHINGTON : 2000

                         LETTER OF TRANSMITTAL


                                    The White House, July 27, 2000.
To the Senate of the United States:
    With a view to receiving the advice and consent of the 
Senate to ratification, I transmit herewith the Treaty Between 
the Government of the United States of America and the 
Government of the United Mexican States on the Delimitation of 
the Continental Shelf in the Western Gulf of Mexico beyond 200 
nautical miles. The Treaty was signed at Washington on June 9, 
2000. The report of the Department of State is also enclosed 
for the information of the Senate.
    The purpose of the Treaty is to establish a continental 
shelf boundary in the western Gulf of Mexico beyond the outer 
limits of the two countries' exclusive economic zones where 
those limits do not overlap. The approximately 135-nautical-
mile continental shelf boundary defines the limit within which 
the United States and Mexico may exercise continental shelf 
jurisdiction, particularly oil and gas exploration and 
    The Treaty also establishes procedures for addressing the 
possibility of oil and gas reservoirs that extend across the 
continental shelf boundary.
    I believe this Treaty to be fully in the interest of the 
United States. Ratification of the Treaty will facilitate the 
United States proceeding with leasing an area of continental 
shelf with oil and gas potential that has interested the U.S. 
oil and gas industry for several years.
    The Treaty also reflects the tradition of cooperation and 
close ties with Mexico. The location of the boundary has not 
been in dispute.
    I recommend that the Senate give early and favorable 
consideration to this Treaty and give its advice and consent to 

                                                William J. Clinton.
                          LETTER OF SUBMITTAL


                                       Department of State,
                                          Washington, July 5, 2000.
The President,
The White House.
    The President: I have the honor to submit to you the Treaty 
between the Government of the United States of America and the 
Government of the United Mexican States on the Delimitation of 
the Continental Shelf in the Western Gulf of Mexico beyond 200 
Nautical Miles (the ``Treaty''). The Treaty was signed in 
Washington on June 9, 2000. I recommend that the Treaty be 
transmitted to the Senate for its advice and consent to 
    The Treaty defines the limits within which each Party may 
exercise its sovereign rights over the seabed and subsoil of 
the continental shelf, in the area in the western Gulf of 
Mexico beyond the limits of their respective exclusive economic 
zones (EEZs), in the area known as the ``Western Gap,'' for the 
purpose of exploring the shelf and exploiting its natural 
resources, particularly oil and gas.
    The boundaries separating the exclusive economic zones of 
the Parties were established in the Treaty on Maritime 
Boundaries between the United States of America and the United 
Mexican States, signed at Mexico City May 4, 1978, which 
entered into force November 13, 1997 (``1978 Treaty'').
    The Treaty is the culmination of negotiations that followed 
the 1978 Treaty's entry into force. It achieves the U.S. 
objectives of delimiting a boundary consistent with the 
approach taken in previous U.S.-Mexico boundary treaties, while 
at the same time adequately addressing issues of oil and 
natural gas reservoirs in the area covered under the Treaty. In 
recommending Senate advice and consent to the ratification of 
the 1978 Treaty establishing the EEZ maritime boundary, the 
Senate Foreign Relations Committee noted:

        the untapped reserves of crude oil and natural gas in 
        the Gulf of Mexico along the 200 nautical mile boundary 
        and the technological advances that have made it more 
        likely that U.S. companies will recover these oil and 
        gas deposits. * * * Delimitation of the western gap has 
        become increasingly important to U.S. interests as 
        petroleum exploration has moved into deeper waters.

    The Committee urged the Administration ``to commence 
negotiations on the western gap without delay, once this treaty 
enters into force.'' (Sen. Exec. Rpt. No. 105-4, pages 5-6, 
Oct. 22, 1997.)
Breadth of the continental shelf
    Mexico and the United States are parties to the 1958 Geneva 
Convention on the Continental Shelf (the ``1958 Convention''). 
Article 1 of the 1958 Convention provides that the continental 
shelf of a coastal State extends beyond a depth of 200 meters 
to ``where the depth of superjacent waters admits of the 
exploitation of the natural resources'' of the shelf. The 1982 
United Nations Convention on the Law of the Sea, to which 
Mexico is a party and which the United States considers 
reflects customary international law in this respect, provides 
a more scientifically-based definition of the continental 
shelf. Article 76 provides that the continental shelf of a 
coastal State comprises the greater of either the area in which 
the seabed and subsoil of the submarine areas extend beyond a 
country's territorial sea throughout the natural prolongation 
of its land territory to the outer edge of the continental 
margin, or the area to a distance of 200 nautical miles from 
the baselines from which the breadth of the territorial sea is 
measured. Under both definitions, the coastal State has 
exclusive control over the exploration and exploitation of the 
natural resources, including oil and gas, of the continental 
    With respect to areas beyond 200 nautical miles from 
coastal baselines, the 1958 Convention and the 1982 United 
Nations Convention on the Law of the Sea provide that certain 
criteria must be met to qualify as continental shelf. During 
the negotiations, both sides agreed that all of the seabed and 
subsoil of the submarine areas beyond the 200-mile EEZ limit in 
the Western Gulf of Mexico meet the legal requirements 
described in both Conventions.
    The treaty consists of nine articles and two annexes.

Continental shelf boundary

    Article I describes the continental shelf boundary between 
the United States and Mexico in the Western Gulf of Mexico 
beyond 200 nautical miles as geodetic lines connecting the 
listed 16 turning and terminal points. In keeping with the 
methodology used in previous U.S.-Mexico maritime boundary 
treaties, this line represents an equidistant line drawn from 
the respective U.S. and Mexican coastal baseline, including the 
baselines of islands.
    Article II sets out the technical parameters of the 
boundary. It states that, for the purposes of the boundary, the 
1983 North American Datum (``NAD 83'') and the International 
Earth Rotation Service's Terrestrial Reference Frame (``ITRF 
92'') are considered identical, and that the terminal points 
are the terminal points of the 1978 Treaty. This article is 
needed to ensure that the Treaty may be applied uniformly and 
accurately by the United States, Mexico and all other users. 
Further, the article states that, for the purpose of 
illustration only, a map depicting the boundary is attached to 
the treaty as Annex 1.
    Article III sets forth the agreement of the Parties that, 
north of the boundary, Mexico will not, and south of the 
boundary, the United States will not, claim or exercise for any 
purpose sovereign rights or jurisdiction over the seabed and 
subsoil. This provision is contained in all modern maritime 
boundary treaties to which the United States is a party.

Transboundary reservoirs

    In addition to the provisions typically found in maritime 
boundary delimitation agreements, the Treaty contains a new set 
of provisions contained in Articles IV and V dealing with the 
subject of possible oil or natural gas (hereinafter, 
``petroleum'') reservoirs that may extend across the 
continental shelf boundary (hereinafter, ``transboundary 
reservoirs''). These provisions, among other things, create a 
framework by which the Parties can exchange information to help 
determine the possible existence of transboundary reservoirs. 
Should any transboundary reservoir be identified, the Parties 
commit to address the equitable and efficient development of 
any such reservoirs. Those procedures are described in more 
detail below.
    Article IV(1) creates a buffer zone, called ``the Area,'' 
which comprises a continental shelf area of 1.4 nautical miles 
on each side of the boundary. (For the United States, the Area 
comprises 9.77 percent of its portion of the Western Gap.) 
Within the Area, the Parties agree to a ten-year moratorium on 
petroleum drilling or exploitation. By its terms, the 
moratorium does not apply to other continental shelf 
activities. Each Party's right to authorize or permit petroleum 
drilling or exploitation outside the Area within the Western 
Gap on its side of the boundary is unaffected by this 
    Article IV(2) provides that the Area is shown on an 
illustrative map at Annex 2 of the Treaty.
    Article IV(3) establishes that the Parties may modify the 
10-year moratorium applicable in the Area by mutual agreement 
through an exchange of diplomatic notes. This provision will 
enable the Parties to shorten or to extend the duration of the 
moratorium should they both agree.
    Article IV(4) requires each Party, on its side of the 
boundary within the Area and in accordance with its national 
laws and regulations, to facilitate requests from the other 
Party to authorize geological and geophysical studies for 
determining the possible presence and distribution of 
transboundary reservoirs.
    Article IV(5) requires that each Party, with respect to the 
Area in its entirety and in accordance with its national laws 
and regulations, share geological and geophysical information 
in its possession in order to determine the possible existence 
and location of transboundary reservoirs.
    Article IV(6) obliges each Party, if it has knowledge of 
the existence or possible existence of any transboundary 
reservoir to notify the other Party.
    During the course of the negotiations each Party supplied 
the other a written summary of their respective national laws 
and regulations pertaining tooffshore oil and gas development 
that would currently be applicable pursuant to the terms of Article IV.
    Article V of the Treaty details a mechanism for 
communication and cooperation between the Parties with respect 
to the Area and the possible existence and location of 
transboundary reservoirs.
    Article V(1) provides that that the Parties, with respect 
to the Area during the ten year moratorium, shall:
  --meet periodically for the purpose of identifying, locating, 
        and determining the geological and geophysical 
        characteristics of transboundary reservoirs as 
        geological and geophysical information is generated 
        that facilitates the Parties' knowledge about the 
        possible existence of such reservoirs (including 
        information provided under Article IV(5);
  --seek to reach agreement for the efficient and equitable 
        exploitation of such transboundary reservoirs; and
  --consult within sixty days of receipt of a written request 
        by a Party through diplomatic channels, to discuss 
        matters related to possible transboundary reservoirs.
    Article V(2) further requires, with respect to the Area, 
that following the ten-year moratorium, the Parties shall:
  --inform the other Party both of its decisions to lease, 
        license, grant concessions, or otherwise make 
        available, portions of the Area for petroleum or 
        natural gas exploration or development and when 
        petroleum or natural gas resources are to commence 
        production; and
  --ensure that entities it authorizes to undertake activities 
        in the Area observe the terms of the Treaty.

Dispute resolution and consultations

    Article VI requires the Parties to consult to discuss any 
issue regarding the interpretation or implementation of the 
Treaty upon the written request by a Party through diplomatic 
    Article VIII provides that any dispute concerning the 
interpretation or application of the Treaty must be resolved by 
negotiation or other peaceful means as may be agreed upon by 
the Parties.

Final clauses

    Article VII provides that the boundary established in the 
Treaty does not affect or prejudice in any manner the positions 
of either Party with respect to the extent of internal waters, 
of the territorial sea, of the high seas, or of sovereign 
rights or jurisdiction for any other purpose. This is a 
standard provision in modern U.S. maritime boundary treaties.
    Article IX provides that the Treaty is subject to 
ratification and that it will enter into force on the date the 
Parties exchange instruments of ratification.
    No new legislation is needed for the United States to meet 
its obligations under the treaty.
    All interested agencies and departments join the Department 
of State in recommending that the Treaty delimiting the 
continental shelf boundary beyond 200 nautical miles between 
Mexico and the United States be transmitted to the Senate as 
soon as possible for its advice and consent to ratification.
    Respectfully submitted,
                                                Madeleine Albright.