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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 14pt; FONT-FAMILY: Times New Roman"><strong>UNITED
      STATES</strong></font></div>
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      AND EXCHANGE COMMISSION </strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>Washington,
      D.C. 20549 </strong></font></div>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 14pt; FONT-FAMILY: Times New Roman"><strong>FORM
      8-K</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>CURRENT
      REPORT </strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>Pursuant
      to Section 13 or 15(d) of the Securities Exchange Act of 1934
</strong></font></div>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>Date
      of Report (Date of earliest event reported): May 25, 2006</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">
      <hr style="COLOR: black" align="center" noshade size="1" width="15%">
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 14pt; FONT-FAMILY: Times New Roman"><strong>GRAN
      TIERRA ENERGY INC.</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 12pt; FONT-FAMILY: Times New Roman"><strong>(</strong></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>f/k/a
      GOLDSTRIKE INC.</strong></font><font style="DISPLAY: inline; FONT-SIZE: 12pt; FONT-FAMILY: Times New Roman"><strong>)
      </strong></font></div>
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      name of registrant as specified in its charter) </strong></font></div>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">
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          <tr>
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            <td align="left" valign="bottom" width="1%">&#160;</td>
            <td align="left" valign="middle" width="25%">&#160;</td>
            <td align="left" valign="bottom" width="1%">&#160;</td>
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              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman"><strong>(State
                or other jurisdiction</strong></font></div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman"><strong>of
                incorporation)</strong></font></div>
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                File Number)</strong></font></div>
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                Employer</strong></font></div>
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                Number)</strong></font></div>
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          <tr>
            <td valign="middle" width="39%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>300,
                611 - 10</strong></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><sup><strong>th</strong></sup></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>
                Avenue S.W.</strong></font></div>
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            <td valign="middle" width="37%">&#160;</td>
          </tr>
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            <td valign="top" width="39%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>Calgary,
                Alberta, Canada</strong></font></div>
            </td>
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              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>T2R
                0B2</strong></font></div>
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          <tr>
            <td valign="top" width="39%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman"><strong>(Address
                of principal executive offices)</strong></font></div>
            </td>
            <td align="left" valign="bottom" width="2%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
            </td>
            <td valign="top" width="37%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman"><strong>(Zip
                Code)</strong></font></div>
            </td>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>(403)
      265-3221</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 8pt; FONT-FAMILY: Times New Roman"><strong>(Registrant&#8217;s
      telephone number, including area code) </strong></font></div>
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      the
      appropriate box below if the Form 8-K filing is intended to simultaneously
      satisfy the filing obligation of the registrant under any of the following
      provisions (see General Instruction A.2. below): </font></div>
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                communications pursuant to Rule 425 under the Securities Act (17
                CFR
                230.425) </font></div>
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                material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
                240.14a-12) </font></div>
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                communications pursuant to Rule 14d-2(b) under the Exchange Act (17
                CFR
                240.14d-2(b)) </font></div>
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          <tr>
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                communications pursuant to Rule 13e-4(c) under the Exchange Act (17
                CFR
                240.13e-4(c)) </font></div>
            </td>
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      </table>
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">&#160;</div>
    <div id="PGBRK" style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
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    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ITEM
      1.01.</strong></font><font id="TAB2" style="COLOR: black; LETTER-SPACING: 27pt">&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ENTRY
      INTO A MATERIAL DEFINITIVE AGREEMENT</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font id="TAB1" style="MARGIN-LEFT: 36pt"></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">On
      May
      25, 2006, Gran Tierra Energy Inc. (&#8220;Gran Tierra&#8221; or the &#8220;Company&#8221;) entered into
      a Securities Purchase Agreement (the &#8220;Agreement&#8221;), dated as of May 25, 2006,
      with Crosby Capital, LLC (&#8220;Crosby&#8221;) to acquire all of the limited partnership
      interests of Argosy Energy International (&#8220;Argosy&#8221;) and all of the issued and
      outstanding capital stock of Argosy Energy Corp. (&#8220;AEC&#8221;), a Delaware corporation
      and the general partner of Argosy. Argosy, a Utah limited partnership, holds
      a
      diverse portfolio of producing properties, drill-ready prospects and exploration
      acreage in Colombia. </font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Argosy&#8217;s
      oil production averaged approximately 987 barrels per day (after royalty) during
      the fourth quarter of 2005. Argosy&#8217;s remaining proven reserves at December 31,
      2005 are estimated at 2.34 million barrels, with probable reserves of 1.50
      million barrels (all net after royalty). Royalty rates are 20% and 8% for
      Argosy&#8217;s producing properties. Argosy&#8217;s net land position is approximately
      153,000 acres. The material terms of Gran Tierra&#8217;s acquisition of Argosy were
      first disclosed in a Current Report on Form 8-K filed with the Securities and
      Exchange Commission on April 7, 2006. </font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font id="TAB1" style="MARGIN-LEFT: 36pt"></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
      consideration to be paid by Gran Tierra for the limited partnership interests
      of
      Argosy and the capital stock of AEC includes a $37.5 million cash payment,
      the
      issuance to Crosby of $3.5 million of Gran Tierra&#8217;s common stock and
      participation rights (including overriding royalty interests and net profit
      interests) in Argosy&#8217;s assets valued at $1 million. Closing of the transaction
      is scheduled to occur as soon as practicable, but in no event later than July
      21, 2006. If the Agreement terminates prior to closing, Gran Tierra is obligated
      to pay a break-up fee of $3.5 million, payable in either cash or in shares
      of
      Gran Tierra&#8217;s common stock. For each day after June 30, 2006 that the
      transaction has not closed, the break-up fee will increase by $25,000 per day,
      payable only in cash. </font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font id="TAB1" style="MARGIN-LEFT: 36pt"></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
      Agreement contains standard representations and warranties, as well as
      pre-closing and post-closing covenants of the parties. The closing of the
      transaction is subject to customary conditions to closing, as well as Gran
      Tierra&#8217;s ability to close, contemporaneously with or prior to the
      closing,&#160;financing with net proceeds of no less than $41 million.
</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
      text
      of the Agreement is filed as Exhibit 10.18 to this Current Report on Form 8-K
      and is incorporated herein by reference. </font><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ITEM
      5.03.</strong></font><font id="TAB2" style="COLOR: black; LETTER-SPACING: 27pt">&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>AMENDMENT
      TO ARTICLES OF INCORPORATION. </strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">On
      June
      1, 2006, Gran Tierra filed a Certificate of Amendment (the &#8220;Amendment&#8221;) to its
      Articles of Incorporation with the Secretary of State of the State of Nevada
      increasing its authorized capital stock from 80,000,001 shares to 325,000,001
      shares, including: 300,000,000 shares of common stock, par value $0.001,
      25,000,000 shares of preferred stock, par value $0.001, and 1 share, par value
      of $0.001, to be designated as Special Voting Stock. </font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font id="TAB1" style="MARGIN-LEFT: 36pt"></font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
      Amendment was approved unanimously by Gran Tierra&#8217;s Board of Directors and
      submitted to stockholders for approval. The Amendment was consented to and
      approved by the written consent, in lieu of a meeting, of the holders of a
      majority of Gran Tierra&#8217;s issued and outstanding shares eligible to vote.
</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div id="PGBRK" style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
      <div id="FTR">
        <div id="GLFTR" style="WIDTH: 100%" align="left">
        </div>
      </div>
      <div id="PN" style="PAGE-BREAK-AFTER: always">
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
        </div>
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
          <hr style="COLOR: black" noshade size="2">
        </div>
      </div>
      <div id="HDR">
        <div id="GLHDR" style="WIDTH: 100%" align="right">
        </div>
      </div>
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ITEM
      9.01.</strong></font><font id="TAB2" style="COLOR: black; LETTER-SPACING: 27pt">&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>FINANCIAL
      STATEMENTS AND EXHIBITS</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(d)
      Exhibits.</font></div>
    <div>
      <table cellpadding="0" cellspacing="0" width="100%">

          <tr>
            <td align="left" valign="top" width="12%" style="border-bottom: black thin solid;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>Exhibit
                No.</strong></font></div>
            </td>
            <td align="left" valign="top" width="58%" style="border-bottom: black thin solid;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>Description</strong></font></div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="12%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">3.5</font></div>
            </td>
            <td align="left" valign="top" width="58%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Certificate
                of Amendment to Articles of Incorporation, filed </font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">June
                1, 2006. </font></div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="12%">&#160;</td>
            <td align="left" valign="top" width="58%">&#160;</td>
          </tr>
          <tr>
            <td align="left" valign="top" width="12%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">10.18</font></div>
            </td>
            <td align="left" valign="top" width="58%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Securities
                Purchase Agreement, dated as of May 25, 2006, by and between Gran
                Tierra
                Energy Inc. and Crosby Capital, LLC. </font></div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="12%">&#160;</td>
            <td align="left" valign="top" width="58%">&#160;</td>
          </tr>

      </table>
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div><br>
    <div id="PGBRK" style="MARGIN-LEFT: 0pt; WIDTH: 100%; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
      <div id="FTR">
        <div id="GLFTR" style="WIDTH: 100%" align="left">
        </div>
      </div>
      <div id="PN" style="PAGE-BREAK-AFTER: always">
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
        </div>
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
          <hr style="COLOR: black" noshade size="2">
        </div>
      </div>
      <div id="HDR">
        <div id="GLHDR" style="WIDTH: 100%" align="right">
        </div>
      </div>
    </div><br>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>SIGNATURES</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">In
      accordance with the requirements of the Exchange Act, the registrant caused
      this
      report to be signed on its behalf by the undersigned, thereunto duly
      authorized.</font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">
      <table align="center" bgcolor="#ffffff" border="0" cellpadding="0" cellspacing="0" width="100%">

          <tr valign="top" bgcolor="#ffffff">
            <td width="50%"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">&#160;</font></td>
            <td width="1%"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">&#160;</font></td>
            <td width="49%"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">&#160;</font></td>
          </tr>
          <tr valign="top" bgcolor="#ffffff">
            <td><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">&#160;</font></td>
            <td colspan="2"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: "><strong>Gran
              Tierra Energy Inc</strong><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">.</font></font></td>
          </tr>
          <tr valign="top" bgcolor="#ffffff">
            <td><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">&#160;<br>&#160;</font></td>
            <td><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">&#160;<br>&#160;</font></td>
            <td><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">&#160;<br>&#160;</font></td>
          </tr>
          <tr valign="top" bgcolor="#ffffff">
            <td>&#160;</td>
            <td><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">By:&#160;&#160;</font></td>
            <td><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">/s/&#160;James
              Hart</font></td>
          </tr>
          <tr valign="top" bgcolor="#ffffff">
            <td colspan="2"><font style="FONT-FAMILY: " size="1">&#160;</font></td>
            <td align="left">
              <hr style="COLOR: black" align="left" noshade size="2" width="80%"><font size="2">Name:
              James Hart</font></td>
          </tr>
          <tr valign="top" bgcolor="#ffffff">
            <td colspan="2"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">&#160;</font></td>
            <td><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: ">Title:
              Chief Financial Officer</font></td>
          </tr>
          <tr valign="top" bgcolor="#ffffff">
            <td colspan="2">&#160;</td>
            <td>&#160;</td>
          </tr>
          <tr valign="top" bgcolor="#ffffff">
            <td colspan="2">&#160;</td>
            <td><font size="2">Date: June 1, 2006</font></td>
          </tr>

      </table>
    </div>
    <div style="DISPLAY: block; MARGIN-LEFT: 288pt; TEXT-INDENT: -54pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div>&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 234pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div><br>
    <div id="PGBRK" style="MARGIN-LEFT: 0pt; WIDTH: 100%; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
      <div id="FTR">
        <div id="GLFTR" style="WIDTH: 100%" align="left">
        </div>
      </div>
      <div id="PN" style="PAGE-BREAK-AFTER: always">
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
        </div>
        <div style="WIDTH: 100%; TEXT-ALIGN: center">
          <hr style="COLOR: black" noshade size="2">
        </div>
      </div>
      <div id="HDR">
        <div id="GLHDR" style="WIDTH: 100%" align="right">
        </div>
      </div>
    </div><br>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>EXHIBIT
      INDEX</strong></font></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center">
      <table cellpadding="0" cellspacing="0" width="100%">

          <tr>
            <td align="left" valign="top" width="12%" style="border-bottom: black thin solid;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>Exhibit
                No.</strong></font></div>
            </td>
            <td align="left" valign="top" width="58%" style="border-bottom: black thin solid;">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>Description</strong></font></div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="12%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">3.5</font></div>
            </td>
            <td align="left" valign="top" width="58%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Certificate
                of Amendment to Articles of Incorporation, filed </font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">June
                1, 2006. </font></div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="12%">&#160;</td>
            <td align="left" valign="top" width="58%">&#160;</td>
          </tr>
          <tr>
            <td align="left" valign="top" width="12%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">10.18</font></div>
            </td>
            <td align="left" valign="top" width="58%">
              <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Securities
                Purchase Agreement, dated as of May 25, 2006, by and between Gran
                Tierra
                Energy Inc. and Crosby Capital, LLC. </font></div>
            </td>
          </tr>
          <tr>
            <td align="left" valign="top" width="12%">&#160;</td>
            <td align="left" valign="top" width="58%">&#160;</td>
          </tr>

      </table><br></div>
    <div>&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
    <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
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{"company-data": {"conformed-name": "GRAN TIERRA ENERGY, INC.", "cik": "0001273441", "assigned-sic": "1311", "irs-number": "000000000", "state-of-incorporation": "NV", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "333-111656", "film-number": "06880896"}, "business-address": {"street1": "300, 611-10TH AVENUE S.W.", "city": "CALGARY", "state": "A0", "zip": "T2R 0B2", "phone": "(403) 265-3221"}, "mail-address": {"street1": "300, 611-10TH AVENUE S.W.", "city": "CALGARY", "state": "A0", "zip": "T2R 0B2"}, "former-company": [{"former-conformed-name": "GOLDSTRIKE INC", "date-changed": "20040113"}, {"former-conformed-name": "GOLKSTRIKE INC", "date-changed": "20031216"}]}
Unassociated Document
UNITED
      STATES
SECURITIES
      AND EXCHANGE COMMISSION
Washington,
      D.C. 20549
FORM
      8-K
CURRENT
      REPORT
Pursuant
      to Section 13 or 15(d) of the Securities Exchange Act of 1934
Date
      of Report (Date of earliest event reported): May 25, 2006
GRAN
      TIERRA ENERGY INC.
(
f/k/a
      GOLDSTRIKE INC.
)
(Exact
      name of registrant as specified in its charter)
Nevada
333-111656
98-0479924
(State
                or other jurisdiction
of
                incorporation)
(Commission
                File Number)
(I.R.S.
                Employer
Identification
                Number)
300,
                611 - 10
th
Avenue S.W.
Calgary,
                Alberta, Canada
T2R
                0B2
(Address
                of principal executive offices)
(Zip
                Code)
(403)
      265-3221
(Registrant's
      telephone number, including area code)
Check
      the
      appropriate box below if the Form 8-K filing is intended to simultaneously
      satisfy the filing obligation of the registrant under any of the following
      provisions (see General Instruction A.2. below):
¨
Written
                communications pursuant to Rule 425 under the Securities Act (17
                CFR
                230.425)
¨
Soliciting
                material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
                240.14a-12)
¨
Pre-commencement
                communications pursuant to Rule 14d-2(b) under the Exchange Act (17
                CFR
                240.14d-2(b))
¨
Pre-commencement
                communications pursuant to Rule 13e-4(c) under the Exchange Act (17
                CFR
                240.13e-4(c))
ITEM
      1.01.
ENTRY
      INTO A MATERIAL DEFINITIVE AGREEMENT
On
      May
      25, 2006, Gran Tierra Energy Inc. ("Gran Tierra" or the "Company") entered into
      a Securities Purchase Agreement (the "Agreement"), dated as of May 25, 2006,
      with Crosby Capital, LLC ("Crosby") to acquire all of the limited partnership
      interests of Argosy Energy International ("Argosy") and all of the issued and
      outstanding capital stock of Argosy Energy Corp. ("AEC"), a Delaware corporation
      and the general partner of Argosy. Argosy, a Utah limited partnership, holds
      a
      diverse portfolio of producing properties, drill-ready prospects and exploration
      acreage in Colombia.
Argosy's
      oil production averaged approximately 987 barrels per day (after royalty) during
      the fourth quarter of 2005. Argosy's remaining proven reserves at December 31,
      2005 are estimated at 2.34 million barrels, with probable reserves of 1.50
      million barrels (all net after royalty). Royalty rates are 20% and 8% for
      Argosy's producing properties. Argosy's net land position is approximately
      153,000 acres. The material terms of Gran Tierra's acquisition of Argosy were
      first disclosed in a Current Report on Form 8-K filed with the Securities and
      Exchange Commission on April 7, 2006.
The
      consideration to be paid by Gran Tierra for the limited partnership interests
      of
      Argosy and the capital stock of AEC includes a $37.5 million cash payment,
      the
      issuance to Crosby of $3.5 million of Gran Tierra's common stock and
      participation rights (including overriding royalty interests and net profit
      interests) in Argosy's assets valued at $1 million. Closing of the transaction
      is scheduled to occur as soon as practicable, but in no event later than July
      21, 2006. If the Agreement terminates prior to closing, Gran Tierra is obligated
      to pay a break-up fee of $3.5 million, payable in either cash or in shares
      of
      Gran Tierra's common stock. For each day after June 30, 2006 that the
      transaction has not closed, the break-up fee will increase by $25,000 per day,
      payable only in cash.
The
      Agreement contains standard representations and warranties, as well as
      pre-closing and post-closing covenants of the parties. The closing of the
      transaction is subject to customary conditions to closing, as well as Gran
      Tierra's ability to close, contemporaneously with or prior to the
      closing, financing with net proceeds of no less than $41 million.
The
      text
      of the Agreement is filed as Exhibit 10.18 to this Current Report on Form 8-K
      and is incorporated herein by reference.
ITEM
      5.03.
AMENDMENT
      TO ARTICLES OF INCORPORATION.
On
      June
      1, 2006, Gran Tierra filed a Certificate of Amendment (the "Amendment") to its
      Articles of Incorporation with the Secretary of State of the State of Nevada
      increasing its authorized capital stock from 80,000,001 shares to 325,000,001
      shares, including: 300,000,000 shares of common stock, par value $0.001,
      25,000,000 shares of preferred stock, par value $0.001, and 1 share, par value
      of $0.001, to be designated as Special Voting Stock.
The
      Amendment was approved unanimously by Gran Tierra's Board of Directors and
      submitted to stockholders for approval. The Amendment was consented to and
      approved by the written consent, in lieu of a meeting, of the holders of a
      majority of Gran Tierra's issued and outstanding shares eligible to vote.
ITEM
      9.01.
FINANCIAL
      STATEMENTS AND EXHIBITS
(d)
      Exhibits.
Exhibit
                No.
Description
3.5
Certificate
                of Amendment to Articles of Incorporation, filed
June
                1, 2006.
10.18
Securities
                Purchase Agreement, dated as of May 25, 2006, by and between Gran
                Tierra
                Energy Inc. and Crosby Capital, LLC.
SIGNATURES
In
      accordance with the requirements of the Exchange Act, the registrant caused
      this
      report to be signed on its behalf by the undersigned, thereunto duly
      authorized.
Gran
              Tierra Energy Inc
.
By:
/s/ James
              Hart
Name:
              James Hart
Title:
              Chief Financial Officer
Date: June 1, 2006
EXHIBIT
      INDEX
Exhibit
                No.
Description
3.5
Certificate
                of Amendment to Articles of Incorporation, filed
June
                1, 2006.
10.18
Securities
                Purchase Agreement, dated as of May 25, 2006, by and between Gran
                Tierra
                Energy Inc. and Crosby Capital, LLC.